Eminent Technology TRW-17 Subwoofer

Part I: The Only Subwoofer

       I could tell you that the new TRW subwoofer from Eminent Technology is better than other subwoofers, and I'd be right. For the TRW does go far lower in bass frequency than other subwoofers, and does play bass much louder than other subwoofers, and does play bass with much better accuracy, quality, dynamic impact, and transient response than other subwoofers. I could even therefore tell you that the new TRW is the best subwoofer, and I'd be right.
       But it would still be misleading for me to tell you simply that the TRW is better than other subwoofers, or is the best subwoofer, for I would not be telling you the whole truth.
       The whole truth, the scientific, objective truth, is that the new Eminent Technology TRW is the ONLY subwoofer.
       That's a bold assertion. How do we justify it?
       You see, saying simply that the TRW is better than other subwoofers, or is the best subwoofer, implies that the TRW is just another subwoofer, and is merely bigger, better, badder than other subwoofers, i.e. that the TRW is different from other subwoofers merely as a matter of degree. And, admittedly, if we were to look simply at matters of degree, the TRW is indeed better and the best, in all the bass parameters that matter: deeper bass extension, louder quantity of bass, more accurate quality of bass, etc.
       But the TRW is not merely different from other subwoofers in degree. It is also different in kind. The TRW employs a wholly different, radical new subwoofer technology. So its bass performance is also wholly different in kind from other subwoofers, not merely of the same kind and better as a matter of degree.
       So the more complete truth is that the TRW is a whole new animal, a whole new kind of subwoofer. But even telling you simply this would still be misleading. It implies that the TRW merely uses an alternative type of technology, with which conventional subwoofer technology might still be competitive.
       The real truth, the whole truth, goes even beyond this. The TRW does not represent just another alternative subwoofer technology. The TRW is not merely different in kind from other subwoofers. Instead, the TRW is virtually the opposite in kind from other subwoofers. In most crucial conceptual aspects, design principles, engineering parameters, and strengths vs. weaknesses, the TRW is virtually the contrary of conventional subwoofer technology and of all other subwoofers. Now, since wherever there are two contraries, then one at most can be right, and since the TRW is demonstrably very right, it logically follows that all other subwoofers, being contrary, must be very wrong.
       The other subwoofers are so wrong, in the contrary design principles they employ for trying to reproduce bass, that they are not really true subwoofers. These other subwoofers, as you will see by the end of this article's technical analysis, are merely pretenders to the throne. The only true subwoofer is the TRW. So the whole truth, the only truth that does not mislead you, is that the TRW is the ONLY subwoofer.
       Let's take some brief looks at several concrete examples of what we mean by this opposite behavior, so you can better understand why the TRW is the only subwoofer.

A. Opposites in Radiating Area Behavior, and Coupling to Air

       In order to make sound at bass frequencies, a driver must couple effectively to the air, so it can move the air. In order to couple effectively, it must have a large radiating area for bass frequencies. And, as the bass frequency to be reproduced goes lower (and the bass wavelength gets consequently bigger), the driver's radiating area must increase, if the driver is to retain its good coupling to the air for lower bass frequencies.
       Conventional subwoofers fail miserably at achieving this crucial coupling. First, they are crippled by a radiating area that is too small. Furthermore (and the key point here), their cone drivers inherently all have an obvious intrinsic property: the radiating area of the cone stays constant at low frequencies, so the radiating area fails to increase as the bass frequency goes lower. Thus, the coupling effectiveness to the air plummets drastically for conventional subwoofers, for lower bass frequencies. A large conventional subwoofer woofer driver might be OK down to say 40 Hz, but below that it simply cannot couple effectively to the air, so it intrinsically cannot be a good subwoofer.
       The TRW subwoofer is just the opposite. We saw that the cone drivers of conventional subwoofers inherently have the intrinsic property of a constant radiating area that fails to increase at lower bass frequencies, thereby making the coupling effectiveness plummet drastically for all conventional subwoofers. The TRW has the opposite intrinsic property. Its radiating area is not constant with frequency. Instead, the effective radiating area of the TRW inherently does increase, as the bass frequency to be reproduced goes lower. That's what should happen, for a true subwoofer to better retain its effectiveness in coupling to the air -- its ability to drive the air -- at the very low bass frequencies where true subwoofers are supposed to be able to do their job, and do their job well.
       Indeed, the TRW's inherent property of increasing its radiating area at lower frequencies is so impressive that its effective radiating area intrinsically and effortlessly increases enough to actually approach infinity (!!), as the frequency being reproduced approaches DC.
       All this is just the opposite of what we just saw in conventional subwoofers. Conventional subwoofer drivers do not change their radiating area for lower frequencies, so their coupling to the air they must drive plummets drastically at lower bass frequencies. The TRW does change its radiating area with frequency, progressively increasing it as the frequency to be reproduced goes lower, so its coupling to the air stays much better at low bass frequencies than the plummeting coupling of conventional subwoofers. It is the TRW that is behaving closer to how an ideal subwoofer should, while it is the contrary behavior of conventional subwoofers that is wrong, for reproducing low bass.
       So, which of these opposites would you rather have as a subwoofer? Which is the real subwoofer, and which is the pretender? As we said, the TRW is the only subwoofer.

B. Opposites in Reactance

       Consider next reactance, as another example of opposite behavior. Conventional subwoofers have large reactance, plus severe reactance changes, at low frequencies. This reactance comes from the driver's free air resonance, compounded by the resonance of the enclosure volume with this driver, compounded by the resonance of the port or vent (if any). This reactance creates four huge sonic problems, which preclude correct bass reproduction. First, this reactance sets up a barrier fence at a certain frequency, below which the conventional subwoofer cannot go, to reproduce the full bass spectrum. Second, this reactance stores energy and then releases it much later in time (as bass overhang and ringing). This spurious delayed energy release not only creates a phony bass sound (boomy overhang), but also obscures subsequent musical information (of all frequencies) that happens to occur immediately after each bass transient. Third, this reactance robs energy from the initial bass transient (the energy contained in that delayed energy release has to be stolen from somewhere), so the initial attack of bass transients lacks sufficient dynamic impact. Fourth, this reactance grossly corrupts the time domain waveform put out by the conventional subwoofer, so that its contribution to the overall musical transient does not properly add up with and cohere with the waveform put out by the main loudspeaker for this same musical transient.
       But again the new TRW subwoofer is just the opposite, of conventional subwoofers. It does not have any reactance at very low frequencies. Thus, the TRW subwoofer does not evince any of these sonic problems that reactance causes in conventional subwoofers. First, the TRW does not have any barrier fence precluding response to very low frequencies, and can happily reproduce the full spectrum at full amplitude all the way down to DC. Second, the TRW does not have any spurious delayed release of energy, so its bass quality is inherently correct and tightly defined, without any phony boom or overhang. And the TRW also thereby allows you to hear much more information immediately after each bass transient (e.g. the woody timbre of a sounding board), so everything from music to special effects sounds much more real. Third, the TRW does not steal any energy from the initial bass transient, so you get the full dynamic impact of each bass transient, again getting you much closer to sonic reality. Fourth, the time domain waveform put out by the TRW is inherently accurate, instead of inherently screwed up, so its waveform correctly adds up with and coheres with each musical (or sound effects) transient put out by your maim loudspeaker, to give you for the first time in your life a correct, coherent transient. This last point might seem to be the most subtle sonically, but it turns out to actually be the most pervasive, affecting more sounds and more of your listening than you would ever have suspected (as we'll explain below).
       So, which is the real subwoofer, and which is the pretender? As we said, the TRW is the only subwoofer.

C. Opposites in Excursion Limits

       With conventional subwoofer cone drivers, the cone excursion increases dramatically as the frequency goes lower, for the same power output level. But, as you know, cone drivers have severe limits on the amount of cone excursion they can endure. As cone excursions get larger, various distortions set in, from nonlinearities in the suspensions, and from nonlinearities in the motor (comprising the magnet and voice coil system). Then, as cone excursions get yet larger, cone drivers hit an abrupt stone wall limit, much like amplifier clipping, where they bottom out and simply cannot go any farther (and, if they reach this point, then their distortion gets really gross).
       The TRW subwoofer is just the opposite. It inherently does not have any excursion limits. The TRW's effective excursion can effortlessly get larger and larger and larger, as the reproduced frequency goes lower. Indeed, the TRW inherently can put out pure DC, and in so doing its effective excursion reaches infinity, without effort, without distortion, and without any limits.
       Since subwoofers do have to endure (thanks to basic laws of physics) dramatically increasing excursions when reproducing progressively lower bass frequencies (see discussion below), it is incumbent upon any driver, hoping to function as a true subwoofer, to be able to correctly handle very large, indeed indefinitely large, excursions. The TRW can do this intrinsically and easily, whereas conventional subwoofer drivers cannot do this at all. Again, it is the TRW that is right, and the oppositely behaving conventional subwoofer drivers that are wrong.
       So, which is the real subwoofer, and which is the pretender? As we said, the TRW is the only subwoofer.

D. Opposites in Low Frequency Reach

       In conventional subwoofers, the two factors mentioned above, reactance and excursion limits, each conspire, and both compound together, to set limits on how low in frequency the subwoofer can go. That's why even the biggest, baddest, most expensive subwoofers are doing well if they can make it down to 20 Hz, and simply cannot reach significantly below 20 Hz.
       The TRW subwoofer is just the opposite. The TRW reaches all the way down to zero Hz (DC), and does so effortlessly, since it reaches down to DC as part of its intrinsic nature. The TRW is just the opposite in that it does not have any reactance at very low frequencies, and also in that it does not have any excursion limits.
       Note that there are literally an infinite number of octaves below 20 Hz, down to DC, and the TRW inherently and easily covers this spectral span of an infinite number of octaves below 20 Hz, whereas conventional subwoofers cannot cover this span at all. A subwoofer is supposed to reach as low in frequency as is sonically important, and we'll see below why this requires frequencies way below 20 Hz, indeed nearly down to DC. So a subwoofer that cannot cover these many, sonically important octaves below 20 Hz is not really a subwoofer at all, whereas the TRW that inherently covers these many octaves easily is just the opposite, and does have this capability that every subwoofer worthy of the name should have.
       So, which is the real subwoofer, and which is the pretender? As we said, the TRW is the only subwoofer.

E. Opposites in Transient Response and Accuracy

       As mentioned above, all conventional subwoofers have reactances which make it inherently impossible for them to achieve correct bass transient response, and thereby also make it inherently impossible for them to reproduce bass accurately. Furthermore, these reactances also make their bass energy occur in the wrong phase and at the wrong time. This means that the sonic contribution from all conventional subwoofers inherently cannot possibly add correctly to the sonic signal put out by the main loudspeakers. And this in turn means that the composite sonic signal will necessarily be inaccurate. It also means that the bass energy from conventional subwoofers inherently cannot possibly form the correct pedestal foundation for any and every musical transient and sound effects transient, so these transients (from your system as a whole) cannot possibly achieve the correct dynamic impact, correct peak energy and shape, nor correct sonic quality.
       The TRW subwoofer is just the opposite. Rather than it being inherently impossible to achieve correct transient response, the TRW instead is completely the opposite in that it inherently has perfect bass transient response, so it does achieve virtually perfect bass transient response, and does so with ease. This means that the TRW inherently produces virtually perfect bass accuracy. It also means that the sonic contribution from the TRW subwoofer inherently occurs in the correct phase and time, to add correctly to the sonic signal put out by the main loudspeakers. And this in turn means that the bass energy from the TRW inherently does form the correct pedestal foundation for any and every musical transient and sound effects transient, so all these transients (as put out by your system as a whole) can and do easily achieve the correct dynamic impact, correct peak energy and shape, and correct sonic quality.
       A crucial factor, in being able to achieve accurate bass transient response, is having frequency response all the way down to DC. A subwoofer like the TRW, which does inherently have frequency response down to DC, can correctly reproduce a step waveform, which is the basic test waveform for evaluating bass transient performance. Any subwoofer like conventional subwoofers, which inherently cannot achieve response down to DC and fail to do so by many octaves (indeed an infinity of octaves), cannot correctly reproduce a step waveform (again, the test waveform for evaluating bass transient response), and therefore cannot correctly reproduce any bass transient from program material.
       Furthermore, conventional subwoofers, in the portion of their low frequency response that rolls off and fails to extend down to DC, happen to roll off at a steep rate of 12 dB per octave or worse, and any subwoofer that exceeds a 6dB per octave rolloff steepness will commit even further errors in its bass transient response, which are seen in the step test waveform as overshoot below the zero axis, and possibly also ringing thereafter. The TRW does not have these steep rolloffs, so its transient response does not have overshoot and ringing that make the transient response of conventional subwoofers inaccurate in these further ways.
       As we'll discuss later, accurate bass transient response is audibly crucial, for all kinds of music and sound effects. Every kind of music and sound effect is continually changing, so every sound we care about is a transient, not a steady state tone. This means that the transient response of a loudspeaker, including a subwoofer, crucially affects the correctness, accuracy, naturalness, and reality of every sound we hear from our systems. 
       In all these aspects of transient response, it is the TRW that is right, and conventional subwoofers that are wrong. So, which is the real subwoofer, and which is the pretender? As we said, the TRW is the only subwoofer.

F. Opposites in Multitasking

       Another example of opposite behavior is multitasking. This is probably the most fundamental conceptual distinction between the TRW as opposed to conventional subwoofers. But, because it is a somewhat abstract concept, it might be tricky for you to understand, and tricky for me to adequately convey. So let's start with a simplified rough analogy.

F.1. Two Tasks for One Engine

       Imagine that you are blowing out the candles at your birthday party. The engine you use is (simply speaking) your mouth, and you focus all of its effort on just one task, blowing as much air as you can as fast as you can, so you can output enough acoustic energy to blow out the candles pretty easily. But suppose now that you instead assign two distinct tasks to that same engine, your mouth. Suppose that you try to give your thank you speech, to the assembled guests who have just sung you

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