Yes, Thomas is very passionate, or at least much more so than me when it comes to gear and audio. As to his less humble rhetoric about who among us is a real music enthusiast, most of the real music lovers I've known weren't even audiophiles at all, and had low-fi to mid-fi systems (which isn't to say they're somehow better than we can be - just that there's no absolute connection between the two). I am much more circumspect about not only the possible virtues of my system (it never fools me), but about the possible pros or cons of any particular system approach. But then again, Twl has more experience than me.
The rant about specsmanship is not wholly unjustified, but it's also increasingly not necessary, I think (and especially not in the context of what's been written in this thread, but as Twl says, he wasn't directing it at my arguments per se). At least within the friendly confines of this forum, I think it has somewhat the quality of a straw man. His system is very unusual anyway: not only doesn't he have any output transformer on his tubes, but the whole thing is battery-powered, a virtue which is probably its own best argument for not being able to dump power like a turbine.
I am not in agreement about the term "euphonic" as applied to THD products being a misnomer. I do believe that moderate amounts of low-order harmonic distortion (probably up to a few percent at least, particularly in the lower frequency ranges) can sound pleasing. I also believe this is not true of higher-order products (at least as it applies to stereo systems, as opposed to electronic music-making), but that is the conventional wisdom. I am a tube user myself, and I have often wondered if my preference for this technology is in large part a reflection of a preference for the harmonic 'tube signature' above the harmonic 'solid-state signature' - or maybe even above no detectable signature at all, given the much lower measured distortion levels SS gear can provide.
Oops, there I went talking about measurements. I agree in many ways with Twl that measurements have often obscured due consideration of what our ears hear. I don't think this is because all measurements are worthless, but just because we apparently can't find ways to measure possible unidentified mechanisms that seem to affect what we hear. In the past, it's also been because many folks who fetishize measurements simply haven't concerned themselves with what listeners hear, a fatal mistake from a purely scientific point of view.
But I have a problem with the internal inconsistency of both refuting the supremacy of technically measurable qualities on the one hand, combined with the advancement of this theory of mutual THD cancellation occurring between a single-driver speaker and an SET amp on the other hand. First of all, let me acknowledge that while Twl advances this argument here, he is not responsible for having created it, just promulgating it. I also want to state that Thomas is, in my opinion, more technically competent than myself. But of course those things aren't enough to prevent me from attempting to take him to task a bit on the matter. :-)
Aside from this theory's (to me unmistakable) specious, lift-yourself-up-by-your-own-bootstraps quality, my problem with the argument is mainly one of selectivity in the service of rationalization. I have no qualms with someone taking the position that they will choose to trust their ears first, and if some apparent conflict arises between what they hear and what can be meausured, they will disregard the supposed implications of the measurement as being faulty, incomplete, or irrelevant.
But then you see something like the distortion-cancellation proposal, which reminds me of nothing so much as 'creation science', wherein a belief (creationism) that presumably doesn't depend on observation of the real world for its support gets shaky knees in light of what can be scientifically supported, and cobbles together its own psuedo-scientific 'theory' as a counteractant, despite the predictable fact that it cannot be confirmed by the evidence. That analogy is not meant to imply that preferring the sound of SET's is comparable to a belief system or denying the real world, just that I find it telling when any movement first contests the methods of its opposition based on their having reached different conclusions, but then attempts to put forth a spurious bastardization of those methods as an additional prop for their position.
To me, it's got to be one or the other: either the measurements don't ultimately matter (for potentially valid reasons) and one does not require a plausible (as in confirmable) technical explanation for what cannot be understood in technical terms, or we have to affirm that there will be some connection between what is discoverable by our ears and what is discoverable through testable technical hypothoses.
In other words, if one is going to so eloquently take exception to the applicability of those technical arguments which are testable (as Twl has), then don't try to simultaneously propone one which has not been confirmed in support of your preference. I think a back-to-back rereading of Twl's first argument in favor of the alleged phenomenon of distortion-cancellation and his second argument in disfavor of reliance on technically known and observable phenomena makes the contradiction clear. Simply proposing a technical mechanism which is heretofore unknown does not reconcile the two positions.
A prime reason the distortion-cancellation argument is quite likely just too beautiful to be true is its very quality of not having been tested, because it could have been by now. This theory might well be easy enough to partially confirm or deny through normal measurements taken of the output vs. input from an SET/single-driver combo, comparing it to the same speaker driven by an amp with, say, push-pull SS topology, and also doing the same comparsions using an appropriate multi-way speaker. Somebody please email me when this is done by an SET-supporter showing that the theory proves to be correct (somehow I doubt they'll be rushing to test it).
But while I'm not trusting this theory or the motives behind offering it, neither am I saying that the appeal of SET/high-sensitivity speaker combos is going to be due to their distortion signatures. I am not adverse to giving preliminary credibility to Twl's contention that distortion (or at least some kinds of distortion) might in reality be lower for such combos - at least within limited frequency and level parameters.
My bringing up the matter of extension was not, as assumed by Twl, primarily about the low end of single-driver speakers. Even such conventional audiophiles as John Atkinson have demonstrated long-standing biases toward basically dispensing with the pursuit of non-rolled response in the bottom octave (maybe octave-and-a-half) in their personal systems - in spite of their high-powered amps and multi-way speakers - simply because of the difficulties and compromises involved in trying to do it right. My point was also not focused on any possible extension limitations of SET amps themselves, which can in theory be overcome if the speaker doesn't demand too much in the way of low-end current.
My point had more to do with the HF limitations of a single-driver design (at least with a pistonic dynamic driver; traveling wave designs [Ohm Walsh] or electrostat's are different). Obviously, single-driver operation is not a prerequisite for SET use, but I brought it up partly because of the distortion-cancellation theory's stipulation of an un-crossed-over single-driver design. Twl of course must not be bothered by it in his system, but I can't see any way for a relatively large and massive single driver to equal the HF response and dispersion of tweeters in multi-way designs.
I was also not refering (again as assumed) to intermodulation distortion when I said the THD of a single driver must be higher. I actually remain unconvinced about the legitimacy of supposed deleterious effects from Doppler distortions occurring in wide-bandwidth drivers, but wasn't talking about that anyway. I said what I meant - that THD must go up as a driver is called upon to handle a very wide bandwidth. If the driver is naturally best suited for the lows, THD must be greater in the mids and highs. If optimized for the mids, then in the lows and highs. If the driver could pristinely handle the highs, then distortion would rise rapidly for the mids and lows. I believe that similar tradeoffs must exist for macro- vs. micro-dynamic capabilities as well. The very same concerns, only to a quite lesser degree, apply in first-order multi-way designs like my own Thiels. Again, all these limitations can be looked at as trade-offs, with other compensating inherent virtues perhaps present.
My stressing of volume capability and dynamic headroom is due to my belief that on the whole, audiophiles place too little emphasis on the quality of amplitudinal fidelity. To me, a lack of purity is no more deadly when it comes to destroying the illusion of live than is too-quiet playback (or compressed peaks). Unfortunately, our rooms tend to be the most limiting factor in being able to achieve higher levels with comfort, and I will never consider myself to be a genuine pursuer of the audiophile truth until the time when (or if) I make a comprehensively acoustically designed and treated listening room. Next to the room factor, all this hoo-ha about what type of amp pales in comparision anyway.
I say this because I have had the experience of listening to my own band's playing and singing reproduced for me in such a scientifically designed and implemented space, and over innocuous little self-powered mini-monitors costing less than the average high end MC carts of today, with the audio signal being routed through a mixing board and hundreds of feet of utilitarian cable, I heard a tangible illusion of live reality that put to shame anything I've ever heard through a high end system in a normal (or even a treated normal) listening room or showroom. I can only imagine what a carefully set up high end system would sound like in that room. Talk about not knowing what can be achieved with an audio system - my head kept jerking around in involuntary surprise when the music started, and it was all I could do to keep from pointing 'at' the sound in disbelief like some kind of delerious fool. I could only try to hold myself in my seat thoughout the whole process and not smile too conspicuously (and we didn't even employ purist recording techniques, although it's true that what I'm talking about was the sound of the original master tape). When I play back these recordings on my system, some tonal qualities and such are more complete, but I am no longer in the band's presence, musically or emotionally. Just wanted to put a little perspective on things before I go. :-)
The rant about specsmanship is not wholly unjustified, but it's also increasingly not necessary, I think (and especially not in the context of what's been written in this thread, but as Twl says, he wasn't directing it at my arguments per se). At least within the friendly confines of this forum, I think it has somewhat the quality of a straw man. His system is very unusual anyway: not only doesn't he have any output transformer on his tubes, but the whole thing is battery-powered, a virtue which is probably its own best argument for not being able to dump power like a turbine.
I am not in agreement about the term "euphonic" as applied to THD products being a misnomer. I do believe that moderate amounts of low-order harmonic distortion (probably up to a few percent at least, particularly in the lower frequency ranges) can sound pleasing. I also believe this is not true of higher-order products (at least as it applies to stereo systems, as opposed to electronic music-making), but that is the conventional wisdom. I am a tube user myself, and I have often wondered if my preference for this technology is in large part a reflection of a preference for the harmonic 'tube signature' above the harmonic 'solid-state signature' - or maybe even above no detectable signature at all, given the much lower measured distortion levels SS gear can provide.
Oops, there I went talking about measurements. I agree in many ways with Twl that measurements have often obscured due consideration of what our ears hear. I don't think this is because all measurements are worthless, but just because we apparently can't find ways to measure possible unidentified mechanisms that seem to affect what we hear. In the past, it's also been because many folks who fetishize measurements simply haven't concerned themselves with what listeners hear, a fatal mistake from a purely scientific point of view.
But I have a problem with the internal inconsistency of both refuting the supremacy of technically measurable qualities on the one hand, combined with the advancement of this theory of mutual THD cancellation occurring between a single-driver speaker and an SET amp on the other hand. First of all, let me acknowledge that while Twl advances this argument here, he is not responsible for having created it, just promulgating it. I also want to state that Thomas is, in my opinion, more technically competent than myself. But of course those things aren't enough to prevent me from attempting to take him to task a bit on the matter. :-)
Aside from this theory's (to me unmistakable) specious, lift-yourself-up-by-your-own-bootstraps quality, my problem with the argument is mainly one of selectivity in the service of rationalization. I have no qualms with someone taking the position that they will choose to trust their ears first, and if some apparent conflict arises between what they hear and what can be meausured, they will disregard the supposed implications of the measurement as being faulty, incomplete, or irrelevant.
But then you see something like the distortion-cancellation proposal, which reminds me of nothing so much as 'creation science', wherein a belief (creationism) that presumably doesn't depend on observation of the real world for its support gets shaky knees in light of what can be scientifically supported, and cobbles together its own psuedo-scientific 'theory' as a counteractant, despite the predictable fact that it cannot be confirmed by the evidence. That analogy is not meant to imply that preferring the sound of SET's is comparable to a belief system or denying the real world, just that I find it telling when any movement first contests the methods of its opposition based on their having reached different conclusions, but then attempts to put forth a spurious bastardization of those methods as an additional prop for their position.
To me, it's got to be one or the other: either the measurements don't ultimately matter (for potentially valid reasons) and one does not require a plausible (as in confirmable) technical explanation for what cannot be understood in technical terms, or we have to affirm that there will be some connection between what is discoverable by our ears and what is discoverable through testable technical hypothoses.
In other words, if one is going to so eloquently take exception to the applicability of those technical arguments which are testable (as Twl has), then don't try to simultaneously propone one which has not been confirmed in support of your preference. I think a back-to-back rereading of Twl's first argument in favor of the alleged phenomenon of distortion-cancellation and his second argument in disfavor of reliance on technically known and observable phenomena makes the contradiction clear. Simply proposing a technical mechanism which is heretofore unknown does not reconcile the two positions.
A prime reason the distortion-cancellation argument is quite likely just too beautiful to be true is its very quality of not having been tested, because it could have been by now. This theory might well be easy enough to partially confirm or deny through normal measurements taken of the output vs. input from an SET/single-driver combo, comparing it to the same speaker driven by an amp with, say, push-pull SS topology, and also doing the same comparsions using an appropriate multi-way speaker. Somebody please email me when this is done by an SET-supporter showing that the theory proves to be correct (somehow I doubt they'll be rushing to test it).
But while I'm not trusting this theory or the motives behind offering it, neither am I saying that the appeal of SET/high-sensitivity speaker combos is going to be due to their distortion signatures. I am not adverse to giving preliminary credibility to Twl's contention that distortion (or at least some kinds of distortion) might in reality be lower for such combos - at least within limited frequency and level parameters.
My bringing up the matter of extension was not, as assumed by Twl, primarily about the low end of single-driver speakers. Even such conventional audiophiles as John Atkinson have demonstrated long-standing biases toward basically dispensing with the pursuit of non-rolled response in the bottom octave (maybe octave-and-a-half) in their personal systems - in spite of their high-powered amps and multi-way speakers - simply because of the difficulties and compromises involved in trying to do it right. My point was also not focused on any possible extension limitations of SET amps themselves, which can in theory be overcome if the speaker doesn't demand too much in the way of low-end current.
My point had more to do with the HF limitations of a single-driver design (at least with a pistonic dynamic driver; traveling wave designs [Ohm Walsh] or electrostat's are different). Obviously, single-driver operation is not a prerequisite for SET use, but I brought it up partly because of the distortion-cancellation theory's stipulation of an un-crossed-over single-driver design. Twl of course must not be bothered by it in his system, but I can't see any way for a relatively large and massive single driver to equal the HF response and dispersion of tweeters in multi-way designs.
I was also not refering (again as assumed) to intermodulation distortion when I said the THD of a single driver must be higher. I actually remain unconvinced about the legitimacy of supposed deleterious effects from Doppler distortions occurring in wide-bandwidth drivers, but wasn't talking about that anyway. I said what I meant - that THD must go up as a driver is called upon to handle a very wide bandwidth. If the driver is naturally best suited for the lows, THD must be greater in the mids and highs. If optimized for the mids, then in the lows and highs. If the driver could pristinely handle the highs, then distortion would rise rapidly for the mids and lows. I believe that similar tradeoffs must exist for macro- vs. micro-dynamic capabilities as well. The very same concerns, only to a quite lesser degree, apply in first-order multi-way designs like my own Thiels. Again, all these limitations can be looked at as trade-offs, with other compensating inherent virtues perhaps present.
My stressing of volume capability and dynamic headroom is due to my belief that on the whole, audiophiles place too little emphasis on the quality of amplitudinal fidelity. To me, a lack of purity is no more deadly when it comes to destroying the illusion of live than is too-quiet playback (or compressed peaks). Unfortunately, our rooms tend to be the most limiting factor in being able to achieve higher levels with comfort, and I will never consider myself to be a genuine pursuer of the audiophile truth until the time when (or if) I make a comprehensively acoustically designed and treated listening room. Next to the room factor, all this hoo-ha about what type of amp pales in comparision anyway.
I say this because I have had the experience of listening to my own band's playing and singing reproduced for me in such a scientifically designed and implemented space, and over innocuous little self-powered mini-monitors costing less than the average high end MC carts of today, with the audio signal being routed through a mixing board and hundreds of feet of utilitarian cable, I heard a tangible illusion of live reality that put to shame anything I've ever heard through a high end system in a normal (or even a treated normal) listening room or showroom. I can only imagine what a carefully set up high end system would sound like in that room. Talk about not knowing what can be achieved with an audio system - my head kept jerking around in involuntary surprise when the music started, and it was all I could do to keep from pointing 'at' the sound in disbelief like some kind of delerious fool. I could only try to hold myself in my seat thoughout the whole process and not smile too conspicuously (and we didn't even employ purist recording techniques, although it's true that what I'm talking about was the sound of the original master tape). When I play back these recordings on my system, some tonal qualities and such are more complete, but I am no longer in the band's presence, musically or emotionally. Just wanted to put a little perspective on things before I go. :-)