school of hi-fi
- how to PROPERLY integrate a subwoofer into an audio system and ... more
- don’t look for perfect sound where there's no technical chance of finding it
- different sound from identical speakers positioned with different backgrounds
- how to find the real differences between "normal" and "hi-end" CD players
- balanced or unbalanced interconnections?
- USB audio DACs
- hi-fi magazines?
Please, scroll down to find the articles related to the headlines above.
how to PROPERLY integrate a subwoofer into a hi-fi system and ... more
I want to start this “brief” dissertation on systems with subwoofers, by quoting word for word what audio pro stated on the first page of an old brochure: “everyone needs a subwoofer”.
I think this clear statement is nowadays even more relevant than ever and should appear in a possible “hi-fi bible”, but enriched with an adjective and a specification: "everyone needs a SERIOUS subwoofer PROPERLY SET UP".
Generally speaking, I highly recommend using a top-quality subwoofer (professionally integrated into the system) with ANY sort of speakers. If you consider not only the extension of the frequency response, but the quality of the bass range too (distortion, speed, damping, ringing, and control), NO passive full-range speaker manages to deliver accurate bass and infrabass.
Unlike the mid-high range, the bass and infrabass range is a "nasty beast", and achieving precise reproduction of these frequencies is a difficult challenge even for dedicated active machines, such as serious subwoofers. For passive full-range speakers, it’s just ... a pious wish!
Regardless of the price, the bass and infrabass reproduction of these speakers is usually dissimilar from what is contained in the sound source, especially if they are not placed in their optimal positions (far from corners and walls)!
Even if you don’t have a spectrum analyser, you can easily verify if I’m correct, and additionally, since you’re here, you can also check the accuracy of the entire audio range of your speakers.
Very simply, you just have to get hold of a STAX electrostatic headphones set (or a similar "toy" of other brands) and compare, in real-time, its sound to the sound of the speakers in question, and ... my best wishes! I don't like to be pessimistic, but I could bet you won't have enjoyable surprises!
These headphones are a reference, and their sound is very close to the original sound contained in the source. They are expensive, but, in my opinion, any true audiophile could avoid squandering money on useless accessories and instead invest in a pair that can also last a lifetime.
My STAX SR-Lambda Pro is close to celebrating its 40th birthday and still provides me with emotions! I normally use it during the editing process of my recordings and ... it's pure lust!
Bass and infrabass frequencies are the foundation and an essential part of any musical composition or sonic event. Therefore, they must be reproduced as perfectly as possible and should not be considered “ugly ducklings”! So, in the following paragraphs, I'm going to demonstrate that a quality active subwoofer, when perfectly set up into the system, is essential for preventing your hi-fi system from "booming", and for reproducing a bass drum or an organ as accurately as a violin or a trumpet.
This topic seems challenging because many “esoteric” audiophiles hold a completely different opinion. They believe (or have been misled to believe) that adding a subwoofer will “pollute” the sound of a hi-end system.
Interestingly, I must admit that these audiophiles are "basically" right, but they are surely unaware that the "poor" subwoofer is normally not at fault! Indeed, this happens for the following two reasons alone:
1) the first and most important one is the incorrect setup and integration of the subwoofer into the system. The result is that the "booming" bass from the main speakers, which is very common, is exacerbated by the partial overlap of the subwoofer’s additional output.
This happens because when you buy a subwoofer, it's more than likely (pure euphemism) that you will not be properly instructed by the vendor on how to correctly integrate the new "baby" into the system (assuming he even knows how to do it, which I highly doubt)!
Additionally, subwoofer instruction manuals are usually very plain and lack detailed technical directions as well.
As a result, almost everyone (dare I say everyone) connects the subwoofer(s) in parallel to the main speakers and, in doing so, unwittingly commits a real “setup crime".
2) the second reason concerns the intrinsic quality of the subwoofers! The vast majority of active subwoofers on the market, regardless of their price, are simply composed of an amplifier and a driver(s). They do not utilise advanced electronic technologies to control the driver(s), which is what truly distinguishes high-quality subwoofers. Furthermore, these subwoofers often (and tragically) employ drivers larger than 10". This goes against my belief (supported by precise technical dictates) that, in a hi-end environment, woofers larger than 10" should not exist, and, if this is a must for the active subwoofers, it's a "hyper-must" for the woofers in full range passive speakers!
However, even though these basic subwoofers cannot match the performance of electronically controlled subs, I have to honestly say that, if perfectly set up within the system, they always provide a more accurate and realistic bass-infrabass range than that generated by the passive woofer(s) of the large speakers!
In light of the points mentioned above, I hope audiophiles now start understanding that an emphasised and vulgar bass range of a hi-end system with a subwoofer is not due to the mere addition of the sub. It’s about how the subwoofer has been integrated into the system and its intrinsic quality, which depends on its technology, not its price!
So, if you want to transform (this is the appropriate verb) your system by adding a sub, first of all, you must buy a great one, and my advice is to look for a 10" sub with some electronic control. Even though this may seem odd (but it isn't at all), if I were you I would seriously consider some old 10" audio pro subwoofers. I believe these subs, thanks to their patented ACE-bass technology, have no competitors yet! You could buy one, at a ridiculous price, from someone who wants to sell it (most likely because he has never integrated it into the system correctly, ha, ha!). You may also be interested in knowing that in 1978, audio pro introduced on the market the very first active (ACE-bass patented) subwoofer in the world, the legendary B2-50. Remarkably, after 46 years, it remains unmatched in electronic performance and sound perfection, still delighting the ears of thousands of audiophiles around the world. I’m thrilled and proud to be one of them! Well, if you now have a high-quality subwoofer, I'd like to share how to set up a system with a subwoofer for the best result. A perfect and proper setup is of paramount importance, as the sound of your entire system depends on it. Please also note that the following instructions apply to ANY subwoofer, and not just to audio pro subs. 1) If possible, position the speakers and subwoofer(s) facing the long side of the room. For "boomy" floorstanding speakers, place them as far away as possible from the corners and the back wall. For smaller speakers on stands, you can significantly reduce these distances. Never place speakers or subwoofers inside a piece of furniture, such as a cabinet, or in a semi-enclosed space like a niche. Unlike the speakers, always try to position the subwoofer(s) in a corner or close to it. If that’s not possible, place it at least against a wall. Corners and walls act as natural mechanical amplifiers for sound, so placing the subwoofer there increases its efficiency. This means you can achieve the same sound pressure at a lower volume, reducing distortion and increasing the sub's dynamic range. 2) When you introduce a subwoofer into a hi-fi system, it’s exactly like adding a new “way” to your speaker. Therefore, just as it is essential to cross over two adjacent drivers in any speaker perfectly, the use of a dedicated crossover is mandatory for this addition as well! A crossover consists of a low-pass filter and a high-pass filter. The low-pass filter is not an issue because every active subwoofer has a built-in adjustable low-pass filter. However, the situation is different for your speakers, which lack a high-pass filter. So, this filter must be created (possibly by a good technician) by rolling off the bass range in the amplifier, or directly in the speakers if impossible to do that via the amp. Unfortunately, this is unfamiliar and challenging territory for any audiophile who is not a technician. As a result, NO ONE does it, and this is the REAL REASON why audiophiles "rightly" say that a subwoofer is detrimental! So, to achieve fantastic bass performance when adding a subwoofer, it is absolutely mandatory to always, without exceptions, roll off the deep frequencies in the main speakers. This applies to ALL speakers in the world, whether they are huge floorstanders or mini-monitors. In both cases, doing so creates a perfect crossover point between the main speakers and the subwoofer(s). Furthermore, since the majority of speakers (especially the large ones) tend to have a “hilly” frequency response in the bass range, which causes “booming” bass, applying a roll-off of 6dB/oct in this range helps subdue this issue. This effectively eliminates or at least drastically reduces their "booming". Additionally, rolling off the lowest frequencies in the main speakers increases their dynamic range and speed, while reducing their total distortion. This happens because their woofers no longer struggle (in vain) to reproduce the deepest frequencies, which the subwoofer is better equipped to handle. As a result, the reduced distortion in the woofers of the speakers decreases the production of high-order harmonics that affect their entire audio range. This leads to improved clarity in the mid and high ranges. Moreover, rolling off the deepest frequencies benefits any amplifier too, by increasing its dynamic range and speed, while reducing total harmonic distortion (THD). In the presence of tube amplifiers, this so-called "lightening" brings such remarkable benefits that adding a properly connected, top-quality subwoofer to these systems should be considered compulsory! I can materialise it all by saying that it's like removing a backpack of 10 kg. from a runner's shoulders, indeed! To conclude, thanks to a proper and idyllic "marriage” (call it "crossover") between the main speakers and the subwoofer(s), the low frequencies stop “booming & yowling”, and the infra-low ones are deep, fast, clean and undistorted as if they are carved out of the air! To help you understand what I mean, I'm going to quote the words Scott Bartley, in an old review on FFWD magazine, used to masterfully describe the “bass department” of an audio pro system with a subwoofer (B1-36), perfectly set up by me: ”bass response is wonderfully tight, incredibly fast and, above all, really deep … to create a distortion-free sub-bass effect that feels as though it’s rising up out of the very floor. Call it low-end imaging, if you will”.
Back to the setup, I must sadly remark that electronic manufacturers, including hi-end ones, overlook the importance of incorporating high-pass filters to roll off the bass response on their machines. For a manufacturer, including a passive hi-pass filter with a 6dB/octave slope at three selectable frequencies on a preamp or an amp is extremely easy and inexpensive (a few dollars). So, this oversight is just technical and "cultural" negligence, but it’s enough to create a serious problem for their customers! To my knowledge, the only amps that can do this are the home-theatre ones and the sachem electronics. Anyway, let's now consider what you (or better, a professional) can practically do, to roll off the bass in different types of amplifiers and consequently in the connected speakers: 1) If you are a "happy owner" of sachem electronics, no problems, because these machines are thought and made for any roll-off combination, so a professional will find it very easy to perfectly set up the new sub into the system. 2) If you have an integrated amplifier with no chance of rolling off electronically the frequencies in the bass department, a practical way to solve the problem is to operate on the speakers, adding a high-quality, non-polarised, capacitor (see the values below) in series to the positive wire of each speaker. To do that, you'll disconnect the positive wire of the speaker cable from the positive (marked red or +) binding post of the amplifier. Connect one of the wires of the capacitor (either one) to the red binding post of the amplifier and the other termination to the positive wire of the speaker cable (solder them together). Do the same for the other speaker. However, if the speaker's crossover board is easily accessible, a technician can solder this capacitor directly on it, which is a much "cleaner" solution. The value of these bi-polar capacitors can be 150μF (100V) if your speakers have a nominal impedance of 4Ω, and 300μF (100V) if their impedance is 8Ω. You can find these capacitors in NZ and Australia at Jaycar stores, with part numbers RY-6924 and RY-6932, respectively. I know this is not an “elegant” solution to the problem, but it's the most practical one and, at the end of the day, more than acceptable! 3) For the owners of a preamp and a power amp or monoblocks (with no option to roll off the bass frequencies), a more brilliant solution is available. In this case, it's possible to roll off the signal before it goes into the power amp(s), by inserting a small polypropylene capacitor (possibly a WIMA MKP10) in series with the core of the left and right signal cables (between preamp and amp). Also in this case, a cleaner solution is possible: a technician can solder the small capacitor to the core of the output socket inside the preamplifier, or the core of the input socket of the amplifier. Regarding the capacitance value of these two capacitors, once a professional finds in the "specifications" of the power amp(s) the value of the input impedance, he can easily calculate it, to achieve a 6dB/oct roll-off at the desired frequency. For example, if the input impedance of your amp or monoblock is 13kΩ, the use of a capacitor of 100nF will roll off your frequency response in the bass range at 6dB/oct, with the -3dB point at 122Hz. This method should be adopted by every owner of a preamp and power amp(s), as it benefits not just the speakers but also the amp(s) by not having to reproduce the bass-infrabass frequencies! However, if you send me an email with the data, I can calculate the value of the capacitors for you. NOTE: It remains understood that the method mentioned in point 2) is valid for this configuration too, even if more "primitive". 4) If you have a home-theatre receiver, the solution is straightforward. Regardless of the type of main speakers you use, even if they are as large as a wardrobe (a current tragic trend in hi-end speakers), go to the SPEAKER SETUP menu, and select the SMALL SPEAKERS option for ALL the speakers (front, centre and rear). Now connect the subwoofer to the “Sub-Out” RCA socket(s) of the receiver, using a shielded cable (its quality is not crucial for sound). Many home-theatre receivers also allow to select the roll-off frequency and the slope for the main speakers. If these options are available, it's very easy to flatten the frequency response of "booming" main speakers (to join the sub(s) perfectly) by following these simple steps: select the slope of 6dB/oct on the receiver, and play, only on the main speakers (sub OFF), a well-recorded CD with good bass and infrabass content. Now, starting from 80Hz, you increase the high-pass frequency point until you hear clean bass. In the presence of terrible floorstanders, sometimes, to achieve clean bass, you may have to reach quite high frequencies (180/200Hz): no worries, the essential thing is that the bass must become clean and flat! Next, you need to set up the frequency of the low-pass filter in the sub. Normally, if you have cut the speakers at around 120Hz with a 6dB/oct slope, this knob should be set at 50Hz (12dB/oct, if you can choose the slope). However, if you have chosen a higher frequency for the roll-off point of your main speakers (see the previous paragraph), you could go higher than 50Hz, but never more than 80Hz. You might think that cutting the speakers at 120Hz and setting the sub’s low-pass knob at 50Hz would create a “hole,” but it actually creates a perfect -3dB crossover point at around 80Hz, which is ideal for achieving a flat frequency response at the crossover point. It’s too long to explain why right now, but trust me! However, it's much better to have a small “hole” in the crossover point (practically inaudible at these frequencies), than a small “hill” (very audible)! Be also aware that when you increase the low-pass frequency in your sub, you will increase its distortion and reduce its dynamic range, which is true for every subwoofer on the face of the earth! It's time now to turn on the sub and adjust its level perfectly. With a spectrum analyser, this is an easy operation that takes just a minute, but it’s unlikely that you have one, so you'll find below an empirical method to adjust the infra-bass pressure. First, with any kind of amplifier, you must set up the tone controls (if any) to flat and ensure that no filter is active. For home-theatre receivers, pre-set the system to “stereo mode". As for tone controls, which are a thing of the past, if your preamp, amp, or receiver has them, never use them! Now select a few well-recorded CDs with real infra-bass content (i.e. bass drum or organ). Do not use old CDs that lack very deep content. Be warned that with these CDs, which result from poor original recordings, people with limited experience usually try to achieve a decent infra-bass, which doesn’t exist in the CD, by continuing to turn up the subwoofer’s level knob! To achieve optimal results, select a Telarc CD (they’re renowned for their high-quality recordings, particularly in classical music). If you don’t already have one featuring a well-defined bass drum or organ, consider acquiring one. Then, playing it, adjust the subwoofer’s "level" knob until you’re content with the infra-bass pressure at your listening position. If you find yourself needing to turn the knob past "eleven o’clock" to achieve satisfaction, there might still be an issue with your system setup (I’d recommend checking the sub-out level on your home-theatre receiver if you use one of them). Alternatively, it’s possible that your musical taste and listening habits could use some adjustment! I strongly advise against setting up your subwoofer with an excessive level. Unnatural and overly emphasized bass can lead to listening fatigue and headaches, while also obscuring the clarity of the upper audio frequencies. Finding the right balance is crucial for an enjoyable listening experience! Anyway, if you have set everything up correctly, but still have a “dirty and/or booming” bass, almost certainly you have to blame the main speakers. Here are a few suggestions:1) as mentioned above, if you have the option in the amplifier's setup menu, increase (even up to 180Hz - 6dB/oct, if needed) the crossover frequency for the main speakers and set up the “low pass” knob of the subwoofer around half-way. This is usually an exhaustive solution.2) if that is not an option, try moving the main speakers further away from the corners of the room and from the back wall. Also reduce the length of the speaker cables, which must always be as short as possible (this is a general rule).3) finally, try to move the subwoofer from the corner along the back wall. If the issue persists, you almost certainly have to blame the acoustics of your room. Unfortunately, poor bass quality, and sometimes even issues with mid-high frequencies, aren’t always solely dependent on the audio system itself. Good acoustics in your listening room are crucial for achieving optimal sound quality. In this regard, if you find yourself unlucky, all your efforts might be mercilessly nullified. In such cases, I recommend experimenting by relocating your system to a different part of the room or even trying it out in another room. Sometimes, this simple change can yield miraculous results! It's important to know that a 20Hz frequency has a wavelength of 17 metres, and in a closed room with a diagonal shorter than 8.5 metres, you physically won’t be able to hear this frequency! This means that deep bass requires spacious and open rooms: it can’t properly expand and "go deep" in small, enclosed spaces. The shape of the room is very important too, so avoid rooms with a cubic shape because these rooms are natural generators of “standing waves,” which tend to confuse the bass, killing its clarity. In situations like these, there isn’t much that can be done. However, you can try to enhance the infra-bass potential of your room by opening doors and, if possible, windows too (please don't laugh, I’m very serious about this)! Keep also in mind that pressure, depth, and quality of bass and infra-bass can vary significantly throughout the room. These variations are normal, so aim to tune your system for a flat bass response at your usual listening position. You’ll likely discover that even small adjustments, such as moving your listening point back and forth or up and down, can have a substantial impact. Be even cautious not to position your listening point in the middle of the room or against the back wall. After reading this “treatise” on systems with subwoofers, are there any audiophiles who still believe that a top subwoofer, perfectly set up by a professional, is a detrimental addition to a hi-end system? If so, I’m sadly sorry and concerned for them! A bad bass range is normally the biggest problem for the majority of systems and can only be solved or at least mitigated with the addition of a subwoofer, but it must be correctly set up. Without a subwoofer(s), fixing many serious acoustical issues is impossible, full stop!
My final piece of advice to the “esoteric” audiophiles is this: instead of squandering heaps of money on useless, expensive, “blessed” interconnections and accessories, invest much less money in a great subwoofer and hire a professional to set it up perfectly. It’s like changing your entire system, and ... welcome to the “very restricted” world of the real hi-end, finally! I've tried to avoid overly technical language, and I hope these instructions will help you set up your improved system perfectly, or at least as best as you can. However, if you encounter any issues beyond your reach, please refer to the hi-end doctor page and do not hesitate to contact us.
So, if you want to transform (this is the appropriate verb) your system by adding a sub, first of all, you must buy a great one, and my advice is to look for a 10" sub with some electronic control. Even though this may seem odd (but it isn't at all), if I were you I would seriously consider some old 10" audio pro subwoofers. I believe these subs, thanks to their patented ACE-bass technology, have no competitors yet! You could buy one, at a ridiculous price, from someone who wants to sell it (most likely because he has never integrated it into the system correctly, ha, ha!). You may also be interested in knowing that in 1978, audio pro introduced on the market the very first active (ACE-bass patented) subwoofer in the world, the legendary B2-50. Remarkably, after 46 years, it remains unmatched in electronic performance and sound perfection, still delighting the ears of thousands of audiophiles around the world. I’m thrilled and proud to be one of them! Well, if you now have a high-quality subwoofer, I'd like to share how to set up a system with a subwoofer for the best result. A perfect and proper setup is of paramount importance, as the sound of your entire system depends on it. Please also note that the following instructions apply to ANY subwoofer, and not just to audio pro subs. 1) If possible, position the speakers and subwoofer(s) facing the long side of the room. For "boomy" floorstanding speakers, place them as far away as possible from the corners and the back wall. For smaller speakers on stands, you can significantly reduce these distances. Never place speakers or subwoofers inside a piece of furniture, such as a cabinet, or in a semi-enclosed space like a niche. Unlike the speakers, always try to position the subwoofer(s) in a corner or close to it. If that’s not possible, place it at least against a wall. Corners and walls act as natural mechanical amplifiers for sound, so placing the subwoofer there increases its efficiency. This means you can achieve the same sound pressure at a lower volume, reducing distortion and increasing the sub's dynamic range. 2) When you introduce a subwoofer into a hi-fi system, it’s exactly like adding a new “way” to your speaker. Therefore, just as it is essential to cross over two adjacent drivers in any speaker perfectly, the use of a dedicated crossover is mandatory for this addition as well! A crossover consists of a low-pass filter and a high-pass filter. The low-pass filter is not an issue because every active subwoofer has a built-in adjustable low-pass filter. However, the situation is different for your speakers, which lack a high-pass filter. So, this filter must be created (possibly by a good technician) by rolling off the bass range in the amplifier, or directly in the speakers if impossible to do that via the amp. Unfortunately, this is unfamiliar and challenging territory for any audiophile who is not a technician. As a result, NO ONE does it, and this is the REAL REASON why audiophiles "rightly" say that a subwoofer is detrimental! So, to achieve fantastic bass performance when adding a subwoofer, it is absolutely mandatory to always, without exceptions, roll off the deep frequencies in the main speakers. This applies to ALL speakers in the world, whether they are huge floorstanders or mini-monitors. In both cases, doing so creates a perfect crossover point between the main speakers and the subwoofer(s). Furthermore, since the majority of speakers (especially the large ones) tend to have a “hilly” frequency response in the bass range, which causes “booming” bass, applying a roll-off of 6dB/oct in this range helps subdue this issue. This effectively eliminates or at least drastically reduces their "booming". Additionally, rolling off the lowest frequencies in the main speakers increases their dynamic range and speed, while reducing their total distortion. This happens because their woofers no longer struggle (in vain) to reproduce the deepest frequencies, which the subwoofer is better equipped to handle. As a result, the reduced distortion in the woofers of the speakers decreases the production of high-order harmonics that affect their entire audio range. This leads to improved clarity in the mid and high ranges. Moreover, rolling off the deepest frequencies benefits any amplifier too, by increasing its dynamic range and speed, while reducing total harmonic distortion (THD). In the presence of tube amplifiers, this so-called "lightening" brings such remarkable benefits that adding a properly connected, top-quality subwoofer to these systems should be considered compulsory! I can materialise it all by saying that it's like removing a backpack of 10 kg. from a runner's shoulders, indeed! To conclude, thanks to a proper and idyllic "marriage” (call it "crossover") between the main speakers and the subwoofer(s), the low frequencies stop “booming & yowling”, and the infra-low ones are deep, fast, clean and undistorted as if they are carved out of the air! To help you understand what I mean, I'm going to quote the words Scott Bartley, in an old review on FFWD magazine, used to masterfully describe the “bass department” of an audio pro system with a subwoofer (B1-36), perfectly set up by me: ”bass response is wonderfully tight, incredibly fast and, above all, really deep … to create a distortion-free sub-bass effect that feels as though it’s rising up out of the very floor. Call it low-end imaging, if you will”.
Back to the setup, I must sadly remark that electronic manufacturers, including hi-end ones, overlook the importance of incorporating high-pass filters to roll off the bass response on their machines. For a manufacturer, including a passive hi-pass filter with a 6dB/octave slope at three selectable frequencies on a preamp or an amp is extremely easy and inexpensive (a few dollars). So, this oversight is just technical and "cultural" negligence, but it’s enough to create a serious problem for their customers! To my knowledge, the only amps that can do this are the home-theatre ones and the sachem electronics. Anyway, let's now consider what you (or better, a professional) can practically do, to roll off the bass in different types of amplifiers and consequently in the connected speakers: 1) If you are a "happy owner" of sachem electronics, no problems, because these machines are thought and made for any roll-off combination, so a professional will find it very easy to perfectly set up the new sub into the system. 2) If you have an integrated amplifier with no chance of rolling off electronically the frequencies in the bass department, a practical way to solve the problem is to operate on the speakers, adding a high-quality, non-polarised, capacitor (see the values below) in series to the positive wire of each speaker. To do that, you'll disconnect the positive wire of the speaker cable from the positive (marked red or +) binding post of the amplifier. Connect one of the wires of the capacitor (either one) to the red binding post of the amplifier and the other termination to the positive wire of the speaker cable (solder them together). Do the same for the other speaker. However, if the speaker's crossover board is easily accessible, a technician can solder this capacitor directly on it, which is a much "cleaner" solution. The value of these bi-polar capacitors can be 150μF (100V) if your speakers have a nominal impedance of 4Ω, and 300μF (100V) if their impedance is 8Ω. You can find these capacitors in NZ and Australia at Jaycar stores, with part numbers RY-6924 and RY-6932, respectively. I know this is not an “elegant” solution to the problem, but it's the most practical one and, at the end of the day, more than acceptable! 3) For the owners of a preamp and a power amp or monoblocks (with no option to roll off the bass frequencies), a more brilliant solution is available. In this case, it's possible to roll off the signal before it goes into the power amp(s), by inserting a small polypropylene capacitor (possibly a WIMA MKP10) in series with the core of the left and right signal cables (between preamp and amp). Also in this case, a cleaner solution is possible: a technician can solder the small capacitor to the core of the output socket inside the preamplifier, or the core of the input socket of the amplifier. Regarding the capacitance value of these two capacitors, once a professional finds in the "specifications" of the power amp(s) the value of the input impedance, he can easily calculate it, to achieve a 6dB/oct roll-off at the desired frequency. For example, if the input impedance of your amp or monoblock is 13kΩ, the use of a capacitor of 100nF will roll off your frequency response in the bass range at 6dB/oct, with the -3dB point at 122Hz. This method should be adopted by every owner of a preamp and power amp(s), as it benefits not just the speakers but also the amp(s) by not having to reproduce the bass-infrabass frequencies! However, if you send me an email with the data, I can calculate the value of the capacitors for you. NOTE: It remains understood that the method mentioned in point 2) is valid for this configuration too, even if more "primitive". 4) If you have a home-theatre receiver, the solution is straightforward. Regardless of the type of main speakers you use, even if they are as large as a wardrobe (a current tragic trend in hi-end speakers), go to the SPEAKER SETUP menu, and select the SMALL SPEAKERS option for ALL the speakers (front, centre and rear). Now connect the subwoofer to the “Sub-Out” RCA socket(s) of the receiver, using a shielded cable (its quality is not crucial for sound). Many home-theatre receivers also allow to select the roll-off frequency and the slope for the main speakers. If these options are available, it's very easy to flatten the frequency response of "booming" main speakers (to join the sub(s) perfectly) by following these simple steps: select the slope of 6dB/oct on the receiver, and play, only on the main speakers (sub OFF), a well-recorded CD with good bass and infrabass content. Now, starting from 80Hz, you increase the high-pass frequency point until you hear clean bass. In the presence of terrible floorstanders, sometimes, to achieve clean bass, you may have to reach quite high frequencies (180/200Hz): no worries, the essential thing is that the bass must become clean and flat! Next, you need to set up the frequency of the low-pass filter in the sub. Normally, if you have cut the speakers at around 120Hz with a 6dB/oct slope, this knob should be set at 50Hz (12dB/oct, if you can choose the slope). However, if you have chosen a higher frequency for the roll-off point of your main speakers (see the previous paragraph), you could go higher than 50Hz, but never more than 80Hz. You might think that cutting the speakers at 120Hz and setting the sub’s low-pass knob at 50Hz would create a “hole,” but it actually creates a perfect -3dB crossover point at around 80Hz, which is ideal for achieving a flat frequency response at the crossover point. It’s too long to explain why right now, but trust me! However, it's much better to have a small “hole” in the crossover point (practically inaudible at these frequencies), than a small “hill” (very audible)! Be also aware that when you increase the low-pass frequency in your sub, you will increase its distortion and reduce its dynamic range, which is true for every subwoofer on the face of the earth! It's time now to turn on the sub and adjust its level perfectly. With a spectrum analyser, this is an easy operation that takes just a minute, but it’s unlikely that you have one, so you'll find below an empirical method to adjust the infra-bass pressure. First, with any kind of amplifier, you must set up the tone controls (if any) to flat and ensure that no filter is active. For home-theatre receivers, pre-set the system to “stereo mode". As for tone controls, which are a thing of the past, if your preamp, amp, or receiver has them, never use them! Now select a few well-recorded CDs with real infra-bass content (i.e. bass drum or organ). Do not use old CDs that lack very deep content. Be warned that with these CDs, which result from poor original recordings, people with limited experience usually try to achieve a decent infra-bass, which doesn’t exist in the CD, by continuing to turn up the subwoofer’s level knob! To achieve optimal results, select a Telarc CD (they’re renowned for their high-quality recordings, particularly in classical music). If you don’t already have one featuring a well-defined bass drum or organ, consider acquiring one. Then, playing it, adjust the subwoofer’s "level" knob until you’re content with the infra-bass pressure at your listening position. If you find yourself needing to turn the knob past "eleven o’clock" to achieve satisfaction, there might still be an issue with your system setup (I’d recommend checking the sub-out level on your home-theatre receiver if you use one of them). Alternatively, it’s possible that your musical taste and listening habits could use some adjustment! I strongly advise against setting up your subwoofer with an excessive level. Unnatural and overly emphasized bass can lead to listening fatigue and headaches, while also obscuring the clarity of the upper audio frequencies. Finding the right balance is crucial for an enjoyable listening experience! Anyway, if you have set everything up correctly, but still have a “dirty and/or booming” bass, almost certainly you have to blame the main speakers. Here are a few suggestions:1) as mentioned above, if you have the option in the amplifier's setup menu, increase (even up to 180Hz - 6dB/oct, if needed) the crossover frequency for the main speakers and set up the “low pass” knob of the subwoofer around half-way. This is usually an exhaustive solution.2) if that is not an option, try moving the main speakers further away from the corners of the room and from the back wall. Also reduce the length of the speaker cables, which must always be as short as possible (this is a general rule).3) finally, try to move the subwoofer from the corner along the back wall. If the issue persists, you almost certainly have to blame the acoustics of your room. Unfortunately, poor bass quality, and sometimes even issues with mid-high frequencies, aren’t always solely dependent on the audio system itself. Good acoustics in your listening room are crucial for achieving optimal sound quality. In this regard, if you find yourself unlucky, all your efforts might be mercilessly nullified. In such cases, I recommend experimenting by relocating your system to a different part of the room or even trying it out in another room. Sometimes, this simple change can yield miraculous results! It's important to know that a 20Hz frequency has a wavelength of 17 metres, and in a closed room with a diagonal shorter than 8.5 metres, you physically won’t be able to hear this frequency! This means that deep bass requires spacious and open rooms: it can’t properly expand and "go deep" in small, enclosed spaces. The shape of the room is very important too, so avoid rooms with a cubic shape because these rooms are natural generators of “standing waves,” which tend to confuse the bass, killing its clarity. In situations like these, there isn’t much that can be done. However, you can try to enhance the infra-bass potential of your room by opening doors and, if possible, windows too (please don't laugh, I’m very serious about this)! Keep also in mind that pressure, depth, and quality of bass and infra-bass can vary significantly throughout the room. These variations are normal, so aim to tune your system for a flat bass response at your usual listening position. You’ll likely discover that even small adjustments, such as moving your listening point back and forth or up and down, can have a substantial impact. Be even cautious not to position your listening point in the middle of the room or against the back wall. After reading this “treatise” on systems with subwoofers, are there any audiophiles who still believe that a top subwoofer, perfectly set up by a professional, is a detrimental addition to a hi-end system? If so, I’m sadly sorry and concerned for them! A bad bass range is normally the biggest problem for the majority of systems and can only be solved or at least mitigated with the addition of a subwoofer, but it must be correctly set up. Without a subwoofer(s), fixing many serious acoustical issues is impossible, full stop!
My final piece of advice to the “esoteric” audiophiles is this: instead of squandering heaps of money on useless, expensive, “blessed” interconnections and accessories, invest much less money in a great subwoofer and hire a professional to set it up perfectly. It’s like changing your entire system, and ... welcome to the “very restricted” world of the real hi-end, finally! I've tried to avoid overly technical language, and I hope these instructions will help you set up your improved system perfectly, or at least as best as you can. However, if you encounter any issues beyond your reach, please refer to the hi-end doctor page and do not hesitate to contact us.
don't look for perfect sound where there's no technical chance of finding it
The purpose of this page is to "try" to stop audiophiles from squandering fortunes in the foolish exercise of expecting to get top sound from very expensive, but technically "hopeless", hi-end speakers.
Well, I'm perfectly aware that I’m wasting my time, but I consider it a duty, or rather almost a "humanitarian" rescue mission, so I must at least try!
As a first consideration, I believe that the term “hi-end” is very often used abusively nowadays! Indeed, normal three-way speakers (70s style), with equally normal low technology, are automatically classified as hi-end if they feature a wonderful solid wood cabinet, polished like a mirror, and an unjustifiably exorbitant price! It seems that audiophiles have totally lost common sense and any contact with the real world. Have they ever asked themselves how much a car should cost proportionately if they pay $50k (or more) for a pair of speakers? Definitely much more than $50m!
Many people might not know that the most expensive part of a speaker is the cabinet, as the industrial cost of woofers, midranges, tweeters, and crossovers is relatively low. While the designer’s research time should be considered, it’s worth noting that research time in car design is exponentially higher. Therefore, considering these factors, a pair of loudspeakers priced over $15K should be seen as a joke unless the cabinet is made from exotic, fragrant wood, with solid gold inlays!
I have to add that lately, high-end design and production are experiencing a sad and incredible process of technical involution, instead of evolution! The analogue and vinyl have been exhumed, and in terms of speaker design, there is a return to the "technology" of the 70s! The manufacturers have started producing huge passive speakers again (the bigger, the better), with the only high-end aspect being the ridiculous, stratospheric price!
Regarding these "the bigger, the better" speakers, I am reminded of what was very rightly stated in an old (1980) audio pro's brochure: we call "phone booths" those speakers that fight a losing battle with the dimensions of domestic rooms and have been designed this way due to a lack of technology.
I fully agree with this sacrosanct statement. So, in the context of domestic hi-end audio, I’m against this new trend of huge "dinosaur speakers", which I will henceforth amicably call "dino(s)".
I start by saying that the perfect loudspeaker doesn’t exist, but it's possible to get close enough if its design adheres to the principles of acoustic physics and strikes the best compromise between technical parameters and sonic priorities. A speaker like that won’t necessarily be expensive, because there is no real reason for it to be. Remember, it’s NOT the price that guarantees quality, but the technical skill of the designer, who must keep things as simple as possible and not defy the basic rules of acoustic physics! Surely you will agree that in hi-end speaker design, this should be the norm, but I assure you it isn’t. To illustrate my point with a simple example, imagine dream cars (Ferrari, Porsche, Aston Martin, Bugatti, etc.) sporting “beautiful” octagonal wheels!
You might think I’m exaggerating, but it’s exactly like that! The only difference is that with octagonal wheels, anyone can immediately note the “small” technical problem, but, with speakers, aberrations of this magnitude aren’t as obvious to most audiophiles because they are much less intuitive and require some knowledge of acoustic physics too.
The utopian, theoretically perfect loudspeaker would resemble the point of a needle, as this design would not be affected by physical issues such as diffraction, refraction, phase, time alignment, and interaction between drivers. While it’s impossible to create such a speaker, depending on the desired sound pressure and bass extension, the motto should always be “the smaller, the better” to minimise these negative effects.
With the addition of a subwoofer, the main speakers don’t need to produce deep bass, which is a great advantage because it allows for a drastic reduction in cabinet size. In fact, the large cabinets of the “dinos” are solely intended to extend the bass response of the woofer(s). However, they never manage to achieve the deep, clean, controlled, and fast infra-bass of a good active subwoofer. Moreover, the large dimensions of their front panels, due to the big woofers, make it impossible to minimise the negative effects of diffraction, refraction, phase issues, etc., in the mid-high range.
Furthermore, many designers of these large speakers, perhaps to impress and/or justify the ridiculous price, often use multiple drivers per way instead of just one. Someone should explain to me why this is necessary for domestic use, where a good sat-sub system can easily achieve live “rock concert” sound pressure levels. The only advantage I can think of is that doubling any driver increases the sound emission by 3dB, which reduces distortion, at the same required level. However, using multiple identical drivers also significantly increases diffraction, refraction, phase issues, and interaction between drivers, resulting in a muddy, unfocused sound and "funny" imaging. To make a long story short, and generalizing, these “dinos” defy the basic rules of acoustic physics that I studied in Secondary School, not at University! They are like dream cars with “octagonal” wheels!
However, to be honest, I have to say that some designers of "dinos" have taken the technical approach more seriously. In some speakers, they house the tweeter and midrange (fortunately only one per way) in small pods, vertically aligned above the large cabinet of the woofer(s). In other speakers, they create "mega" D'Appolito configurations, aligning, in a very tall and impressive box, two midbass drivers with the tweeter in the centre, and big woofers (the more, the merrier) above and below.
Even if these speakers, at the end of the day, are normal "dinos", they at least adhere to the main rules of acoustic physics and, for this reason, should sound better than those with a big front panel full of drivers.
It is nonetheless interesting to note that these speakers are practically two-way speakers with passive woofers! So, my logical and straightforward question is: why didn't the designers of these “dinos” make a pair of nice, two-way bookshelf speakers with separate active subwoofers, instead of two large speakers with passive woofers? Were they afraid of creating something well-sounding? Something smaller, easily positionable and adjustable, even when placed in a suboptimal location?
I don’t want to think they are a plethora of hopeless technicians, so there must be another reason!
Yes, and in my view the reason is that they probably know it’s impossible, or at least I hope so, to sell two small speakers and two subwoofers for $50k or more! Even the most gullible audiophile might realize someone is making fun of him!
On the contrary, it’s very possible to achieve that with huge speakers, and for the manufacturer, it’s definitely worth it! The funny thing is that audiophiles don’t realise that even this way, they are being taken for a ride, and ... for a "longer one" too!
I do prefer a pair of top-sounding 2-way on stands, along with one (or two) serious active subwoofer(s), perfectly set up, and I'm going to explain why.
Very simple 2-way slim floorstanders or bookshelf speakers on stands, with a semi-oval cabinet to reduce internal standing waves and a front panel not wider than the largest component on it, capable of producing high sound pressure with low distortion, and with a crossover point between mid-woofer and tweeter around 2.5kHz or higher, are nowadays the best possible speakers for reproducing sound from 80Hz upwards.
Indeed, such a speaker should have only one tweeter and one mid-woofer, or, even better, one tweeter and two mid-woofers in a pure D’Appolito configuration (two vertical mid-woofers with the tweeter in the centre between them), which is the best for imaging.
Please don't faint, but my piece of advice is to buy two top centre speakers! A centre speaker usually produces very accurate sound because the designers know that it's the most important speaker in a home theatre system, so they pay particular attention to it.
But that's not all: by setting them up vertically on 60/70 cm. stands, you automatically obtain speakers in pure D'Appolito configuration. Additionally, due to their dimensions and not being natural "boomers", you can optimally position them in locations impossible for the “dinos". Now, the only problem left is to reproduce the frequencies below 80Hz and … the deeper, the faster, the cleaner, the better! You'll do it by adding one (or two) top-quality subwoofer(s), integrated into the system by a professional.
Such sat-sub systems will easily outperform hi-end "dinos", not only because they are more respectful of the laws of acoustic physics, but also for many other reasons, as outlined below:
>> a sat-sub system is a bi-amplified system and this means that the main speakers and their amps (properly rolled off on the bass range, to join the sub) have to cover only the range from around 80Hz upwards. This is an immense joy for the speakers, and also a lovely gift to any amp, but a galactic gift to all tube amps, indeed! Furthermore, a bi-amplified system with sub(s) has a much higher "speed" and dynamics, compared to a traditional "dino" with large passive woofers. The “speed,” also known as “transient response,” is one of the most important parameters of a hi-fi system. It’s a peculiarity of every musical instrument too! An organ has no speed, but percussions and “plucked” string instruments have a high “speed.” If your system is “slow”, it will "fade" the soul and sound of those instruments. Many audiophiles believe that a harpsichord is easy for a system to reproduce, but they are badly mistaken. Slow systems (which I mercilessly call “funeral systems”) can handle an organ, but they only pretend to reproduce the true essence of a harpsichord (if seriously recorded!). It’s even worse with percussions, and you surely can’t imagine that a loudly played triangle is "food" for only a few systems! However, it's interesting (or sad) to note that "gurus" and magazines never mention "speed"! >> a two-way passive crossover for a bookshelf, unlike those for three/four/five-way "dinos", is enormously simpler! If correctly designed, it results in a much faster and time-aligned crossover. >> unlike the “dinos”, small speakers are not natural “boomers”. If needed, you can position them (obviously on stands) close to the back wall or in corners. >> the bass-infrabass range of an electronically controlled active sub has nothing in common with that generated by the big (nowadays, tragically bigger and bigger) passive woofer(s) of the "dinos”: it’s deeper, much faster, fully controlled, damped, and cleaner. It’s exactly like comparing a Bentley to a Ferrari on a winding road! >> the distortion and ringing of an active good sub is always lower than that of passive big woofers! Consequently, its emission of harmonics (generated by distortion in the low spectrum) is much lower, greatly benefiting the mid-high range of the speakers. Why? Simply because these "invented" harmonics, added and distributed with decreasing intensity across the entire audio band, are fewer. To sum up, passive big woofers that attempt to go deep generate unwanted effects on the mid-high spectrum too! Some pathetic audiophile calls it “colour”, but the correct word should be “horror”! >> unlike “dinos”, which, to try to "humanise" the "booming" in the bass-midbass, offer only the chance of being moved around a bit (if possible), a sat-sub system, almost always, can be perfectly tuned for a flat response by a professional, and just this merely sets a gulf between the performance of the two systems! >> to accurately recreate the original image contained in the source, the virtual vision of the performers, and the 3D stage, small speakers with a small front panel are far superior to larger speakers. This statement contradicts the common belief among many audiophiles that larger speakers produce a bigger image. Indeed, they are mistaken. Only small speakers, possibly in a D’Appolito configuration, provide you with a more accurate reproduction of the image if present in the original recording and consequently on the CD. Additionally, the image is linked to the frequency response of a system through the mathematic relation Fourier inversion theorem. Applied to this context, it essentially states that the flatter the frequency response of your system at your listening position, the more accurate the image will be. Therefore, as emphasized earlier, a good satellite-subwoofer system can achieve a flatter frequency response at your listening position than what is achievable with “dinos”, resulting in a better image. >> the total cost of a hi-end system, made from small speakers, sub and appropriate amplification is far lower than the cost of a hi-end system employing "dinos" and high-powered amps. This is a good point for many audiophiles, but I also know that for many others, who want to show off, and for the retailers, it won’t be a pro, but a con. >> small speakers reduce the chances of divorce, but considering this a pro or a con is ... very personal!
>> a sat-sub system is a bi-amplified system and this means that the main speakers and their amps (properly rolled off on the bass range, to join the sub) have to cover only the range from around 80Hz upwards. This is an immense joy for the speakers, and also a lovely gift to any amp, but a galactic gift to all tube amps, indeed! Furthermore, a bi-amplified system with sub(s) has a much higher "speed" and dynamics, compared to a traditional "dino" with large passive woofers. The “speed,” also known as “transient response,” is one of the most important parameters of a hi-fi system. It’s a peculiarity of every musical instrument too! An organ has no speed, but percussions and “plucked” string instruments have a high “speed.” If your system is “slow”, it will "fade" the soul and sound of those instruments. Many audiophiles believe that a harpsichord is easy for a system to reproduce, but they are badly mistaken. Slow systems (which I mercilessly call “funeral systems”) can handle an organ, but they only pretend to reproduce the true essence of a harpsichord (if seriously recorded!). It’s even worse with percussions, and you surely can’t imagine that a loudly played triangle is "food" for only a few systems! However, it's interesting (or sad) to note that "gurus" and magazines never mention "speed"! >> a two-way passive crossover for a bookshelf, unlike those for three/four/five-way "dinos", is enormously simpler! If correctly designed, it results in a much faster and time-aligned crossover. >> unlike the “dinos”, small speakers are not natural “boomers”. If needed, you can position them (obviously on stands) close to the back wall or in corners. >> the bass-infrabass range of an electronically controlled active sub has nothing in common with that generated by the big (nowadays, tragically bigger and bigger) passive woofer(s) of the "dinos”: it’s deeper, much faster, fully controlled, damped, and cleaner. It’s exactly like comparing a Bentley to a Ferrari on a winding road! >> the distortion and ringing of an active good sub is always lower than that of passive big woofers! Consequently, its emission of harmonics (generated by distortion in the low spectrum) is much lower, greatly benefiting the mid-high range of the speakers. Why? Simply because these "invented" harmonics, added and distributed with decreasing intensity across the entire audio band, are fewer. To sum up, passive big woofers that attempt to go deep generate unwanted effects on the mid-high spectrum too! Some pathetic audiophile calls it “colour”, but the correct word should be “horror”! >> unlike “dinos”, which, to try to "humanise" the "booming" in the bass-midbass, offer only the chance of being moved around a bit (if possible), a sat-sub system, almost always, can be perfectly tuned for a flat response by a professional, and just this merely sets a gulf between the performance of the two systems! >> to accurately recreate the original image contained in the source, the virtual vision of the performers, and the 3D stage, small speakers with a small front panel are far superior to larger speakers. This statement contradicts the common belief among many audiophiles that larger speakers produce a bigger image. Indeed, they are mistaken. Only small speakers, possibly in a D’Appolito configuration, provide you with a more accurate reproduction of the image if present in the original recording and consequently on the CD. Additionally, the image is linked to the frequency response of a system through the mathematic relation Fourier inversion theorem. Applied to this context, it essentially states that the flatter the frequency response of your system at your listening position, the more accurate the image will be. Therefore, as emphasized earlier, a good satellite-subwoofer system can achieve a flatter frequency response at your listening position than what is achievable with “dinos”, resulting in a better image. >> the total cost of a hi-end system, made from small speakers, sub and appropriate amplification is far lower than the cost of a hi-end system employing "dinos" and high-powered amps. This is a good point for many audiophiles, but I also know that for many others, who want to show off, and for the retailers, it won’t be a pro, but a con. >> small speakers reduce the chances of divorce, but considering this a pro or a con is ... very personal!
All the above mentioned "pros" of a perfect system with a sub, are summarised and made visible in this screenshot:
This is the screenshot of my portable spectrum analyser, an NTI Minilyzer ML1 (1/3 octave), showing the fantastic frequency response of my system playing pink noise, with the microphone (a Schoeps CMC3-MK2) positioned in my listening point. This result is due to a very accurate setup of a pair of beautiful centre speakers on stands, with a glorious subwoofer.
As you can note, the 20Hz is flat, with 8kHz at -3dB and 16kHz at -6dB, fully respecting the dictates of "its majesty" Brüel & Kjær!
Such a response to pink noise in the listening point must be considered almost utopian and very unlikely for any "dinos" system, regardless of price!
It's quite interesting (and funny too) to know that the current price of the speakers-sub system in question could be less than 5.000 NZ dollars. If you are curious, you can find a detailed list of the components of my system on the live recording page.
Given all this, someone has to explain why the majority of audiophiles have bought and continue to purchase floorstanders and "dinos". If it’s not for showmanship, visual satisfaction, or adhering to the influence of magazines, the only remaining explanation is that these audiophiles probably weren’t aware of the facts outlined in this article!
For sure, hi-fi magazines and esoteric "gurus" have taken great care to keep the audiophiles in the dark about these things, assuming (but not guaranteeing) they know them! However, one thing is certain: they have NO interest in recommending and promoting hi-end sat-sub systems!
Now a few words about different typologies of large speakers, with their pros and cons:
1) Large, dynamic full-range, multi-way (normally multi-driver too), floorstanding speakers (the archetypes of "dinos") - They have several cons as previously mentioned. As for the pros, I struggle to find any beyond their impressive dimensions and aesthetic appeal.
2) Big, dipole speakers (electrostatic, isodynamic, ribbon etc.) - The pros are that, generally, these speakers have quite an accurate timbre and detail, with good "speed" in the mid-high. Considering the cons, there is the problem of their limited dynamic range and sound pressure, as well as an inconsistent infra-bass range. In my opinion, to address these issues, a top-quality and fast 10” active subwoofer, perfectly tuned into the system by a professional, is essential and makes a terrific difference (even in the mid-high range). However, there are other cons: the biggest one is that they are dipole speakers, meaning they emit sound equally from both the front and back. So, the sound emitted from the front reaches your ears at the initial instant (T1). Meanwhile, the sound emitted from the back, born in opposition-of-phase, and reflected by walls, corners, the ceiling, and the floor, arrives at your ears delayed, at various instants (T2, T3, T4, etc.). This results in an out-of-phase sound that doesn’t accurately represent the true size of the instruments (e.g., a violin might sound as big as a piano). Another issue is that, despite the front stage being enjoyably wide, it doesn’t allow for precise localization of the performers. However, when listening to commercial CDs, these problems are less noticeable due to their multi-microphone recording techniques and lower quality. You might even appreciate the larger sound. But with perfect recordings (in phase), the problems and the true nature of the dipole speakers are brought to you on a silver tray and ... ! 3) Big, full-range, dynamic, multi-way floorstander speakers, with an omnidirectional (also called poly-directional) multi-driver head, for the reproduction of the mid-high range - These speakers have the same (actually, even more) cons as the dipole speakers mentioned in the previous paragraph, except for sound pressure. As for the pros, I cannot see any.
4) Large, full-range, loudspeakers with dynamic woofer(s) and dynamic horn drivers for the mid and high range. A particular, quite long, speech has to be addressed to them, but I cannot do that in full here, so I’ll try to be concise, explaining the essentials. Horn drivers can be classified into first, second and third generations. Their only purpose is to increase the sound pressure of a normal driver by a mechanical amplifier, which is the horn. These horn drivers enable the creation of highly efficient loudspeakers (around 100dB 1W/1m), reducing the need for powerful amplifiers. The most-used horns in loudspeakers belong to the first generation, similar to those from 70 years ago. Even using the best possible modern drivers, mounted on modern profiles (Onken, Iwata etc.), they produce a sound affected by heavy colouration and sometimes a nasal timbre too. This happens for the following physical-acoustical reasons: 1 - Alteration of the frequency response, caused by the deformation of the membrane, which is exposed to the high pressures generated in the compression chamber. 2 - Internal resonances, at different frequencies and their multiples, originated inside the compression chamber and the throat. 3 - Resonances generated by the reflections inside the horn, plus high-frequencies diffraction created by the mouth of the horn, along its perimeter.
The second and third generation of these drivers is another story. In the last years, thanks to the use of complex computing programs, in the hands of skilled technicians, a couple of big companies have managed to solve, or at least minimise, the problems exposed above. These companies now produce full-range, high-efficiency speakers (with dynamic woofers and horn drivers for the mid-high frequencies), that are, in my opinion, the best option for listening to music in huge rooms or venues. However, audiophiles must not consider employing these speakers in domestic rooms because they are very large and also designed to achieve a perfect balance at a distance. Regarding the very expensive “hi-end” speakers, constructed with horn drivers and dynamic woofer(s), as far as I know, almost all of them are made by small manufacturers who use horns similar (even if modern) to those of the first generation. Any comment is superfluous. The only “hi-end” aspect they have is the price! Anyway, considering that these speakers represent a very minimal part of the market, a couple of simple questions emerge spontaneously: are these very few manufacturers the only “custodians of the truth”? Is it possible that all the others (the vast majority), who use normal midranges and tweeters, are wrong? I don’t think so. However, these speakers are aesthetically impressive and surely the best possible speakers to show off! 5) Not too big floorstander speakers incorporating top-class active subwoofers. If these speakers are seriously designed, they should be considered the only genuine full-range speakers on the market! Practically, they are similar to sat-sub systems and a good alternative to them. Usually, their mid-high range employs one tweeter and one mid-woofer (or, even better, a D’appolito configuration) and the front panel of the cabinet is as wide as the largest component on it. The active subwoofer is in the lower part of the cabinet and can be side-firing or down-firing. A professional can flatten their frequency response in the listening point without problems!
To finish, there are other different types of speakers, but not being representative and many times "ridiculous" too, I will ignore them. However, the worst thing about the previous categories of speakers, with the only exception of floorstanders with active subs built-in, is that they are outrageously expensive! Nevertheless, technically inexperienced audiophiles are fatally attracted to the large dimensions of these "the bigger, the better" dinos. If they are wealthy enough, they buy them without a second thought. However, when they start discovering the real “soul” of these speakers, they try to fix the issues by purchasing “blessed” cables and insane accessories. They end up squandering another fortune, much to the delight of retailers, with minimal results. In reality, all their efforts only manage to barely smooth the corners of the “octagonal” wheels! Now you can understand the exact meaning of the headline of this article, hopefully!
I’ve intentionally used straightforward, not overly technical language because this topic represents the pinnacle of complexity and importance in the world of hi-fi and hi-end audio, and I would like it to be understood in its essence by every reader. If anyone has questions, curiosities, or specific queries, I'll be delighted to assist and potentially prevent costly missteps.
1) Large, dynamic full-range, multi-way (normally multi-driver too), floorstanding speakers (the archetypes of "dinos") - They have several cons as previously mentioned. As for the pros, I struggle to find any beyond their impressive dimensions and aesthetic appeal.
2) Big, dipole speakers (electrostatic, isodynamic, ribbon etc.) - The pros are that, generally, these speakers have quite an accurate timbre and detail, with good "speed" in the mid-high. Considering the cons, there is the problem of their limited dynamic range and sound pressure, as well as an inconsistent infra-bass range. In my opinion, to address these issues, a top-quality and fast 10” active subwoofer, perfectly tuned into the system by a professional, is essential and makes a terrific difference (even in the mid-high range). However, there are other cons: the biggest one is that they are dipole speakers, meaning they emit sound equally from both the front and back. So, the sound emitted from the front reaches your ears at the initial instant (T1). Meanwhile, the sound emitted from the back, born in opposition-of-phase, and reflected by walls, corners, the ceiling, and the floor, arrives at your ears delayed, at various instants (T2, T3, T4, etc.). This results in an out-of-phase sound that doesn’t accurately represent the true size of the instruments (e.g., a violin might sound as big as a piano). Another issue is that, despite the front stage being enjoyably wide, it doesn’t allow for precise localization of the performers. However, when listening to commercial CDs, these problems are less noticeable due to their multi-microphone recording techniques and lower quality. You might even appreciate the larger sound. But with perfect recordings (in phase), the problems and the true nature of the dipole speakers are brought to you on a silver tray and ... ! 3) Big, full-range, dynamic, multi-way floorstander speakers, with an omnidirectional (also called poly-directional) multi-driver head, for the reproduction of the mid-high range - These speakers have the same (actually, even more) cons as the dipole speakers mentioned in the previous paragraph, except for sound pressure. As for the pros, I cannot see any.
4) Large, full-range, loudspeakers with dynamic woofer(s) and dynamic horn drivers for the mid and high range. A particular, quite long, speech has to be addressed to them, but I cannot do that in full here, so I’ll try to be concise, explaining the essentials. Horn drivers can be classified into first, second and third generations. Their only purpose is to increase the sound pressure of a normal driver by a mechanical amplifier, which is the horn. These horn drivers enable the creation of highly efficient loudspeakers (around 100dB 1W/1m), reducing the need for powerful amplifiers. The most-used horns in loudspeakers belong to the first generation, similar to those from 70 years ago. Even using the best possible modern drivers, mounted on modern profiles (Onken, Iwata etc.), they produce a sound affected by heavy colouration and sometimes a nasal timbre too. This happens for the following physical-acoustical reasons: 1 - Alteration of the frequency response, caused by the deformation of the membrane, which is exposed to the high pressures generated in the compression chamber. 2 - Internal resonances, at different frequencies and their multiples, originated inside the compression chamber and the throat. 3 - Resonances generated by the reflections inside the horn, plus high-frequencies diffraction created by the mouth of the horn, along its perimeter.
The second and third generation of these drivers is another story. In the last years, thanks to the use of complex computing programs, in the hands of skilled technicians, a couple of big companies have managed to solve, or at least minimise, the problems exposed above. These companies now produce full-range, high-efficiency speakers (with dynamic woofers and horn drivers for the mid-high frequencies), that are, in my opinion, the best option for listening to music in huge rooms or venues. However, audiophiles must not consider employing these speakers in domestic rooms because they are very large and also designed to achieve a perfect balance at a distance. Regarding the very expensive “hi-end” speakers, constructed with horn drivers and dynamic woofer(s), as far as I know, almost all of them are made by small manufacturers who use horns similar (even if modern) to those of the first generation. Any comment is superfluous. The only “hi-end” aspect they have is the price! Anyway, considering that these speakers represent a very minimal part of the market, a couple of simple questions emerge spontaneously: are these very few manufacturers the only “custodians of the truth”? Is it possible that all the others (the vast majority), who use normal midranges and tweeters, are wrong? I don’t think so. However, these speakers are aesthetically impressive and surely the best possible speakers to show off! 5) Not too big floorstander speakers incorporating top-class active subwoofers. If these speakers are seriously designed, they should be considered the only genuine full-range speakers on the market! Practically, they are similar to sat-sub systems and a good alternative to them. Usually, their mid-high range employs one tweeter and one mid-woofer (or, even better, a D’appolito configuration) and the front panel of the cabinet is as wide as the largest component on it. The active subwoofer is in the lower part of the cabinet and can be side-firing or down-firing. A professional can flatten their frequency response in the listening point without problems!
To finish, there are other different types of speakers, but not being representative and many times "ridiculous" too, I will ignore them. However, the worst thing about the previous categories of speakers, with the only exception of floorstanders with active subs built-in, is that they are outrageously expensive! Nevertheless, technically inexperienced audiophiles are fatally attracted to the large dimensions of these "the bigger, the better" dinos. If they are wealthy enough, they buy them without a second thought. However, when they start discovering the real “soul” of these speakers, they try to fix the issues by purchasing “blessed” cables and insane accessories. They end up squandering another fortune, much to the delight of retailers, with minimal results. In reality, all their efforts only manage to barely smooth the corners of the “octagonal” wheels! Now you can understand the exact meaning of the headline of this article, hopefully!
I’ve intentionally used straightforward, not overly technical language because this topic represents the pinnacle of complexity and importance in the world of hi-fi and hi-end audio, and I would like it to be understood in its essence by every reader. If anyone has questions, curiosities, or specific queries, I'll be delighted to assist and potentially prevent costly missteps.
different sound from identical speakers positioned with different backgrounds
Just a small percentage of lucky audiophiles have the chance to put the sound system in a room with an optimal rectangular shape. In this case, I highly recommend symmetrically placing the speakers (and the electronics) on one of the short walls facing the long side of the room.
Unfortunately, most of us aren't that lucky and must cope with the reality of the available room at our disposal, which often is anything but regular in shape. Consequently, the surroundings of the left and the right speakers are different!
Well, you should know that the entire midbass-bass-infrabass emission of any speaker is highly influenced and modified by the configuration of the walls around it. Suppose you have to place the two speakers in positions with different background layouts and decor (e.g., one speaker in a corner and the other with just a flat open wall behind it, or an open space, or between two pieces of furniture, etc.). In this case, the unavoidable result is that each speaker will have a different frequency response across the entire low spectrum.
Unfortunately, the differences are even worse for di-pole and omnidirectional speakers, where the mid-high is tragically affected too! To make you understand the severity of this common reality, I'll put it in simple words: it is exactly like employing different speakers for the left and the right channels! A spectrum analyser will mercilessly show you the shocking reality!
If you don't have it, but only a demonstrative CD with a track of "pink noise", play it, and start switching (or balancing) between the left and the right speaker. Even this way, you will clearly and immediately hear the quite unbelievable difference in sound between the two speakers and ... my best wishes for sleeping well the night!
Regarding the CD with "pink noise", in my view, it should be part of the accessories of any audiophile, but just using a normal good CD and an amplifier with mono and balance (you could temporarily reconnect an old one, with "mono" and "balance"), it's more than enough to evaluate the real dimension of this issue.
However, it seems the audiophiles completely ignore this "negligible anomaly" and this is grave because the solution to this problem is among the most important things they should care about! As far as I know, no "guru" or magazine has ever taken into consideration this problem, probably because they have no idea how to fix it exhaustively!
So, if you find yourself in this situation and want to achieve the full potential of your system, you must address this sonic anomaly. Be aware that you cannot solve the problem by squandering money on cables or any esoteric paraphernalia, which might be the "hyper-skilled" advice of some vendor! At least for this time, you must get serious and look for the help of a skilled professional.
This guy, with a spectrum analyser, two great subwoofers, and the chance of rolling off the bass response of the main speakers in the needed way, will achieve the same flat frequency response for both speakers!
Unfortunately, if they are dipole or omnidirectional speakers, nothing can be done to equal the mid-high emission of the two speakers. In my opinion, any audiophile who doesn’t have a room with two identical symmetrical ends should carefully stay away from this type of speaker!
To finish, the audiophile must realize that this is the ONLY possible way to operate, to comprehensively solve this issue and achieve the same sound emission in each speaker, customised for his unique listening environment. It's not a simple operation at all, and, as mentioned before, it's "bread" only for very skilled professionals. This is probably the real reason why all the insiders seem very careful not to "publicise" this problem!
If you have the job done, you will joyfully discover that your system now provides a new and much better sound, coherent, cleaner in the mid-high, free of booming, and finally with a glorious infra-bass too, catching not just "two", but ... "many" birds with one stone!
Please don't hesitate to contact us if you have any doubts, or queries, or need professional help!
how to find the real differences between "normal" and "hi-end" CD players
Even if the CDs and CD players are on the edge of the grave, replaced by any computer and a good DAC, for online streaming at original CD quality (for complete information about this topic, read ”USB audio DACs” on this page), there are still audiophiles who “invest” a lot of money in esoteric CD players. So, the simple question is: is it worth spending $50k, instead of $500, on a CD player?
You can probably already imagine what I personally think about it, but I don't want to influence you, so I’d like to provide you with an unbiased and serious method for deciding unequivocally if it’s worth it, or not. Considering that the sonic differences between CD players are always minimal, the only effective and serious method of evaluating them is real-time switching, which is the only way to avoid any mental conditioning.
Despite the probable hostility of your retailer to this procedure (potentially toxic to his business), you would ask him to connect a "humane" CD player to one input of the preamp of the system you want to use for this trial, and the expensive one to an adjoining input of the same preamp, to allow rapid switching between them in real-time.
Now you have to feed the two machines with two identical, preferably well-recorded and complex CDs, and start playing them, pressing the play buttons at the same instant, for perfect synchronization. From now on, you can switch between the two CD players at any time, but the first thing you have to do is check the levels of the two CD players, which must be identical. If not, the one that’s a bit louder (even minimally) always appears to be the best: it seems clearer, more selective, etc. Regarding the volume problem, there are these different possibilities:
if you are lucky, the two machines already put out the same levels. If not and if both the CD players have fixed outputs, to even the levels, you have to get used to adjusting the volume a bit every time you switch: this is quite imprecise and frustrating, but better than nothing and you have to deal with the fact.
It can also happen that one of the two machines has got a volume control and, if this CD player is the louder one, just reduce its volume for perfect parity. If both the machines have got the volume control, no problems at all, obviously. Enjoy the challenge now! I’m almost sure that you are going to meet some interesting surprises, and you will also understand the possible initial reticence of your retailer!
Now, a few personal considerations:1) the difference in sound between two CD players (if any) is minimal and mostly depends on their analogue sections.2) as usual, in the hi-fi world, galactic and unjustified prices are no guarantee of celestial sound at all! 3) before spending heaps of money on these machines that, at best, can only minimally change the sound of a system, the wise audiophile has to be totally sure about the sound of the more crucial items in his system, particularly the speakers, which are responsible for more than 80% of the final sound.
The funny reality is that a number of these audiophiles own hi-end speakers that are not capable of making evident sonic differences as minute as the ones between CD players! In this case, I advise you to use a great set of electrostatic headphones, or ... just buy the cheapest CD player. To finish and generally speaking, if you are spending important money on components or other stuff, where possible, always use real-time switching, to compare them!
balanced or unbalanced interconnections?
Following the nowadays trend, many hi-end electronics, in addition to the normal unbalanced inputs and outputs, feature balanced inputs and outputs too! So, I think that someone has indeed noted that I have not furnished any of our sachem electronics with balanced inputs and outputs! Why? Are there reasons? Yes, there are, and I explain them below.
Let me start by telling you that balanced lines are peculiar to “professional” equipment, but be also aware that the adjective “professional” is NOT synonymous with top sound quality. In fact, the "professional" stuff is not hi-end in the sound department (some exceptions are possible, but unknown to me). This is sad, and you can consider it as one of the "original sins" of the recorded sound.
However, the primary purpose of balanced lines is to avoid inducted noises in long signal cables, not to improve sound fidelity! For example, in a recording studio or a concert hall, the microphone cables are usually very long (often more than 20/30 metres) and sometimes operate in environments saturated with radio frequencies and/or magnetic fields. In such circumstances, balanced lines are a must, to avoid interference. On the other hand, in the domestic hi-fi world, the interconnections are very short and very well shielded, and the line level is usually higher than in a mic line. For these reasons, it is unlikely (particularly in NZ) that there will be induced noise in your system, so you won’t need balanced lines at all.
Anyway, it's more than easy to verify if you are affected by any inducted noise: using unbalanced lines, turn on the CD player, and, without playing music, just set the volume of the preamp (or amp) as high as possible and ... listen.
As another matter of interest, you may like to know that, apart from very few (if any) electronics, where all the circuits are balanced, the way to obtain a balanced input/output from an unbalanced one and vice versa is by adding an extra electronic circuit to the unbalanced output stage of the "sender" appliance and another circuit to the input stage of the appliance that receives the signal, to convert it in unbalanced again.
Usually, these circuits consist of IC amplifiers, plus resistors and capacitors. These capacitors are in the signal path and normally have a capacitance of around 10μF, which renders the use of polypropylene caps practically impossible, due to their big dimensions. So, everyone uses electrolytic capacitors!
Please note that, regarding the sound, the electrolytic caps are the worst quality capacitors made. A good audio designer tolerates their use if they're the only capacitors "possible" (as in a power supply), or for mandatory space reasons, but just the most starry-eyed audio technician will tell you that putting electrolytic caps in the audio signal path is a good idea!
So, if your line is noise-free, by utilising balanced interconnections, you are listening to two additional (and not the best, sonically speaking) electronic circuits to NO advantage, on the contrary! I don’t know how much they can affect the final sound, but they obviously will.
Even if I never tried, these differences in sound seem confirmed by the judgment of many audiophiles, who say that the sound between balanced and unbalanced lines is not the same, but ... they probably don't know that the real sound of the machine (normally) is that of the unbalanced lines!
In my opinion, in a noise-free hi-end environment and if your machines are not entirely balanced (possible, but extremely rare and ... galactically expensive), it would be better to avoid balanced lines, and, where balanced and unbalanced sockets are on offer, my recommendation is to use the unbalanced ones if you want to listen to the real sound of the machine!
Now you can fully understand why I didn’t fit any sachem electronics out with balanced input/output options: they are serious machines, that don't need any "mirror lures for skylarks" to be sold (probably I'm the usual pathetic dreamer), and I wanted to maintain the signal path “capacitor-free”, which is a paramount peculiarity of the preamp sachem pure.
To provide you with a physical view of these circuits, the photo below shows the ones (left and right channels) employed to convert the output signal from unbalanced to balanced, in my preamp for the microphones. I had to equip this machine with balanced outputs too because some professional recorders feature only balanced inputs. However, my Tascam recorders feature both XLR and RCA input sockets, so ... I use only the unbalanced RCA ones!
the two, black, bipolar electrolytic capacitors are compulsory and both are on the signal path
USB audio DACs
As I mentioned in the above topic "don't look for perfect sound where it cannot be found", some hi-end audiophiles are currently embarking on a somewhat melancholic retroactive technological journey, reminiscent of 70s technology, embracing vinyl, analogue equipment, large woofers, massive speakers, no active subwoofers, and so on. However, there’s another group, the enlightened ones, pursuing a different path: liberating music from the confines of CDs or vinyl-based sources.
With the increasing amount of home automation and electronic integration, the demand for top hi-fi products, which can easily interact with computers, is rising every day, so a good DAC (Digital Audio Converter) has become an essential part of their systems!
Just to say, in my particular case, considering that 90% of the music I normally listen to comes from my live recordings (stored in my large hard disk), the use of a top-sounding USB audio DAC is for me an imperative obligation.
I would also recommend using the combination of the CD/DVD player inside your computer as the transport and a high-quality DAC as the converter for your main CD player. However, nowadays you have at your disposal even cleverer ways to listen to music and one of them is called TIDAL. With TIDAL you can stream over 25 million tracks in original CD quality and 75.000 music video clips in high definition and immaculate sound, making it an online library of original quality music for very demanding audiophiles. You just need a computer (any computer) for streaming and a superior DAC for sound perfection. I mentioned Tidal, which was the first, but now there are many other similar sites for original-quality streaming, at a very low price.
Another piece of advice is directed at the "nostalgic" vinyl lovers, who should (or better, must) know that every time they play an LP, a deterioration occurs, due to the primitive technology of this medium.
Surely I'm not, but if I were one of them, I would digitally record all my LPs on a hard disc, to keep intact forever the sound they have at the time you record them, obviously ... nicely "humanised" by crick-cracks and "lovely" distortion, as the vinyl does, but, at least, immune from further deterioration!
An additional benefit is that later, instead of materially searching for the desired LP to play in a mess of other LPs, you could make a database and find the wanted track just with a click! You could also get eventually rid of the usual, long, "religious" ritual of placing, cleaning, kissing and blessing an LP on the turntable, before playing it!
Regarding the sound quality, if you use a good DAC, the sound will be exactly the same as the original played by the turntable because a digital recorder doesn't make any changes to the sound! Actually, if you record them using headphones for monitoring (not the speakers), the sound should be even better, because it won't be affected by any feedback effect. The feedback is another "joy" of the vinyl world and is related to the volume (the higher, the more), but, even at normal levels, you aren't completely free from its effects.
NOTE: as is often the case in the hi-fi world, the price of an item is not necessarily correlated with its quality and sound. Therefore, I present an empirical method for comparing two different DACs in real time, free from any mental conditioning that might influence judgment, especially when the differences (if any) are minimal. Put a quite complex CD in the CD player of the computer (or use Tidal), connect the two DACs you want to compare to two different USB ports of the computer and connect the output of the DACs to two LINE IN of the preamp or amplifier. Now, switching between the two inputs, you have the sound of the two different DACs in real time.
Anyway, you must be sure that the two DACs play at the same volume! As told before, even a minimal difference in volume is enough to mislead your judgment: the one slightly louder always seems better sounding!
hi-fi magazines?
For sure, hi-fi magazines can be useful, particularly their first pages, where they present new stuff and talk about how the market evolves, and their last pages, usually dedicated to music.
However, the most important pages should be the ones in the middle, dedicated to the reviews of various pieces of gear, but, regarding these reviews, the shrewd audiophile should ask himself a few questions:
Generally, do the reviews reflect reality?
Are they made by serious professionals, with at least good knowledge of sound and live classical music?
Are the reviewers allowed to tell the bare truth?
Well, my answer to all these questions is NO!
In fact, generally speaking, all trade magazines live off advertising revenue more than from their sales, and therefore, the obvious priority of every editor is to make and keep their advertisers "happy"!
So, between magazines and importers (or manufacturers) there is a tacit agreement: if you advertise with us, we review your products, and ... this says everything!
In your experience, are you able to remember at least one review that has spoken badly about a product? Indeed not, and this is the confirmation that there is something not correct, because I assure you that a lot of stuff (sometimes very expensive), which has received glorious reviews, actually should have been panned. However, the best reviewers, very covertly, hint at the true essence of the product, but you have to be very good at "reading between the lines".
Furthermore, it's very unlikely (actually almost impossible) to find a review of an item imported or manufactured by a company that doesn't advertise in the magazine. However, the reviewers are not always in bad faith: in fact, many times they are just incompetent, but this produces the same misleading result. Furthermore, the reviews depend on the personal sonic taste of the reviewers, which could be veeeery different from yours!
I think that the following two paragraphs will be very educational for the audiophiles who take such reviews as gospel truth.
In the Italian hi-fi world, I have been one of the opinion leaders for quite a long time, so, in 1986, I was asked to write two pages, "Fair Go" style, for each monthly issue of the Italian hi-fi magazine "Alta Fedeltà".
It has been very challenging and funny as well, but, just writing in general, not mentioning brands directly (but clear enough for the "usual" reader between the lines), after twelve issues of "politically incorrect" articles, the editor was no longer able to stand the pressure from the advertisers, who, since the very first issue, started to obsess and covertly blackmail him. So, he "kindly" asked me to stop, and, being a good friend of his, ... I did!
Another interesting case, which deserves your reflection, is that, in 1978, when the audio pro's B2-50 (the first active subwoofer and, at that time, something comparable to a green Martian appearing on Earth) went on the market, NO hi-fi magazine acclaimed, reported on, or even mentioned the brand audio pro, its new "baby" called "active subwoofer", and its incredible ACE-bass patented technology!
Indeed, the B2-50 was the very first and only active sub to land on the world's market, so the magazines had no interest in promoting something conceptually very new that had the potential to be a dangerous unsettling factor for the manufacturers of big speakers, and that might lead to a monopoly by a single company in the just-born market for subwoofers. A company, furthermore, that didn't pay for any advertising in national or international hi-fi magazines and that was the holder of such an advanced and unbeatable technology.
So, almost as if by magic, all the magazines "carelessly" ignored audio pro and the first machine in the world capable of reproducing the infra-bass range perfectly!
For the umpteenth time, proof of the genuineness of the magazines, which, once again, didn't miss the opportunity to show how much they care about the reproduction of sound and the interests of their readers. Quite sad, isn't it?
The preceding lines are enlightening and interesting for understanding what actually happens offstage in the magazines, so, dear audiophile, if you have to buy some stuff (particularly if expensive), you may certainly read reviews of it (if any), but be wise and go further: implement your knowledge about the "object of your desire", looking for proper scientific measurements of it, and, visiting "Google Images", have a look at its interior (very important to verify if it's a "festival" of messy cables or seriously designed and built), but mostly, use your ears and a perfect CD, of which you possibly know the content.
If you follow my advice, you will surely be much richer and much more satisfied with the sound of your system! For your information, I gladly stopped reading hi-fi magazines in 1987, with the magical end of bilious attacks, plus a virgin and unbiased approach, when I have to evaluate new gear!
You will find other interesting considerations about reviews and reviewers on the live music vs. hi-fi and the hi-end doctor pages.