Twl, I don't consider the word "euphonic" to signify a bad thing qualitatively; only if such a quality is actually masking higher levels of distortion so as to sway a listener into preferring a version of reality which is farther from the truth does it raise my eyebrows. Otherwise, inevetible distortions should be both low in level and low in order, ideally speaking.
Yes, I've heard about the theory of canceling distortions in SET/single driver systems, but I don't buy it. There is just no way that I can see where, even if you stipulate identical-order and -level distortions (which I strongly doubt can ever be the case, but as you say the theory doesn't depend upon 'identical' to work to some degree), the temporal relationships and the inherent non-linear components will never match up - in whatever phase - to yield much cancellation.
In fact, I don't know why there should really be any cancellation at all: this reversing the leads business is flawed thinking to my mind. The speaker's distortions are *caused* (for the most part) by its response to the input signal. Reversing the phase of that signal will merely do the same for those distortions. (And not even considering for the time being an amp's ability to exert its control over the driver's movement, or whether the reverse occurs.)
Obviously, this isn't a unique indictment of single-driver speakers; any speaker, fed by any type of amp, will receive the amp's output signal - including its embedded distortions - and then further distort that whole signal, amp distortions included. The cancellation argument, were it true, should apply in some measure to any amp/speaker combination; the position that it will only work with low-order distortions makes no sense to me. Besides, SET amps have higher-order distortion products too. They just don't internally cancel the even orders, so the distortion profile tends to be characteristically different than push-pull amps. But it is not exclusively low-order - it is predominantly low-order.
Don't misunderstand me - the combination of class-A operation, simple and few parts and circuits, low or no feedback, and no crossover notch artifacts or device mis-matching or -tracking makes SET's appealing in theory even despite low power and higher total THD levels. Getting a speaker to give of its best under those restrictions can be a different matter, as I'm sure you'd agree.
But rationalizations like the cancellation argument just make me more skeptical than I might be otherwise. Simply the fact that apparently only the SET crowd feels the need to come up with something like this rhetoric points the finger of doubt, to me. The whole case is too facile and unsupported, as far as I can see.
Look at the contention that single-driver speakers will have lower-order distortion, for instance. How so? I have always thought that the wider the bandwidth any one driver is called upon to cover, the higher the THD over its bandwidth that will result. This makes sense, and so does the limited total bandwidth of a speaker which depends on just one driver (dynamic driver, that is). True, other distortions, such as phase distortions and crossover-induced distortions, can be lower. But if you restrict any single driver to operating only within its prime comfort zone, as in a multi-way speaker, THD (as well as non-linearities) must be lower at all orders.
I am not suggesting that higher-power, push-pull amps, of either class-A or -A/B operation, don't have their own characteristic sonic flaws, some of which are unique to their operation and shouldn't be overlooked in the quest for higher power, others of which are merely unmasked by the same (and not unmasked in SET's, presumably due to other, higher-level 'euphonic' distortions). But I don't know that anybody can claim that either type of amp, alone, sounds 'better' than the other, because the partnered speakers tend to be so different.
In that sense, SET owners will tend to have the advantage concerning comparisions, since they could reasonably experiment with higher-powered push-pull amps on their efficient speakers and draw some conclusions, whereas conventional low-impedance, low-efficiency speaker owners (like me) cannot really do the reverse comparision. But the results of such comparisions will not speak directly to the question of whether an SET/single-driver or horn combo will 'outperform' a higher-power/low-to-moderate-efficiency pairing. It almost certainly would depend in large part to the listener's priorities, so all we can definitively say is that all various amp/speaker pairings will sound different from one another.
I am also not saying that the very idea of single-driver speakers doesn't have powerful attractions. Consistent dispersion at all angles, uniform resonance properties, phase coherence, and lack of crossover-induced complications and limitations are all desirable. The trade-offs we already know. If I lived near you, I'd ask to come over and have a listen. I'd even bring my amps.
As things are, all I can do is use my mind the best I can to consider the arguments. I find the cancellation argument implausible, and more than a little ingenuous in its seemingly willful selectivity and dubious premises. I'm not on this thread to make anyone defend their system to me, just to give my own view that power can be used for good as well as evil, particularly in freeing up speaker design possibilities. I have no agenda or animus, just intellectual curiousity and a fondness for playing devil's advocate. |
I think it's funny to say that SET enthusiasts make up things like I stated above, when it is plain that others make up terms like "euphonic distortion", when there is no such thing as "euphonic distortion". Euphonic distortion is a term made up by people who follow specifications, and can't figure out why an amp that doesn't spec like a SS amp can eat it for lunch. That's all it is. A term made up to explain something the number crunchers can't explain. That's because number crunchers alway look at everything in a vacuum, and not in concert with the other stuff it is working with. A bench test is fine with them. It even took us years to get the number crunchers to realize that current capability had something to do with driving a speaker. Now we're still having trouble with the vestigial remains of the "specs race" of the 1970s. Just look at all the amps out there that have damping factors of 1000 and distortion of .00001%. That is simply a result of negative feedback. There is no way any amp can get these numbers without negative feedback, whether they be SS or otherwise. Now we know that negative feedback is counter-productive to good sound. But does that stop these amp makers from using prodigious amounts of it? No. They are selling it to the number crunchers.
When an amp delivers good sound quality and has bench measurements that don't stack up to the negative feedback amps, then there is a scurry of activity to figure out some explanation for it, hence the "euphonic distortion" moniker. After all, there is no way an amp with 1% distortion could sound as good, right? Wrong.
This is not targeted at you Alex, so don't feel like I'm attacking you with this. I'm venting my spleen.
I am giving a feasible explanation to the number crunchers as to how there is a reason that they can understand, in their meager little brains, that there are things that happen outside their little test facility. Things that they didn't even think to test, or even realized existed. Things that they don't even have the foggiest idea are even existing, far from the idea that they even would know how to go about testing them. Number crunchers bring only the lowest form of understanding to the forefront. Virtually every single number crunching spec has resulted in the sonic degradation of the products that followed the results of these tests.
So you can see that I have a very dim view of these number crunchers. And if you look at their track record, you'll see I have very good reason to take this view.
So to get back to the point, the concentration of this harmonic distortion at the 2nd harmonic in both amp and speaker presents a unique possibility for self-cancelling distortion components. Not that every single bit of distortion will be cancelled, but that possibly even a majority will.
I took this position to make an explanation that could show a quantification of this phenomenon, because it is an attempt to explain something that has caused much malignment of the SET amplifier and its enthusiasts, as "lovers of certain types of distortion". This is patently false. SET enthusiasts are some of the most rabid lovers of clear clean and natural sound, in the audiophile world. They just go against the grain of the "normal" way of thinking, which includes ultra inefficient speakers and big boat anchor SS amplifiers with copious amounts of negative feedback. The term "golden midrange" didn't come out of thin air. The reason why it's "golden" has nothing to do with euphonic distortion components, but rather, the lack of them. Most good SET amps have a glorious midrange, that would send even the best SS amps running for cover. The only reason that they are limited to "golden" in the midrange, comes from the limitations of the output transformers. Of course, in my case, I have a SET without any output transformers, and it is one of only a few that can make that claim(only Berning can do it). So my "golden midrange" extends from the top to bottom. And believe me, it does.
Now SETs are not perfect, and I never claimed they were. But they do have the best midrange of any amps there are, and if the transformers were out of the way, they would kill the SS market. At least for the non-number cruncher types.
It's not some kind of SET user delusion. It is a real thing. Whether the number crunchers accept it or not is not of any consequence to me. Their way has always led to a lowering of the bar, not an improvement. If someone wants to move beyond the ordinary, they have to go to the extraordinary, and this means getting out of the mainstream boat. Anyone out of the mainstream is immediately looked at with suspicion because he is not following what all the other lemmings are following. There must be something wrong with him, they all say. Far from it. In this case, there is something very right with him.
Many people cannot move out of the "comfort zone" of peer acceptability. They will never lead, but will only follow when enough others go that way. That is the mark of mediocrity.
If you want to get to the edge of performance, you have to go to the edge to get it.
It is easy for me to understand that what I say is not easily acceptable to most. That doesn't bother me a bit, and in fact I wear it like a badge of honor.
What I stated above about distortion cancelling is an attempt at explaining what is happening, to the naysayers. Even at worst, it is no more incorrect than the term "euphonic distortion", and it may even, in fact, be a correct explanation of why SET amps and single-driver speakers have the "golden" sound that they do. I can tell you with impunity that 64 bipolar transistors running an 84db 5-way speaker will never get you there. I've been around long enough to know that for sure.
|
Alex, your point about single drivers and their covering a wide range, relates to potentially higher intermodulation distortion. This is another thing that has some "questioned" characteristics.
A diaphragm microphone recieves all the frequencies at once, and is also a single element. It is having the high frequencies modulated onto it, while the lower frequencies are making large excursions of the diaphragm, just like the single driver speaker does. Is it possible that the single driver speaker more accurately produces the wave, because it has this inverse relationship to the recording microphone? Possibly.
As far as what amp/speaker is better, this is related directly to the end user, and his knowledge of what good sound is. If the only exposure he has, is to "spec wonders" then he will think that is the way to go, because they don't sound terrible, they just don't sound as good as some other things that are made to sound good, not spec good.
SET's are limited in power, and in speaker selection. This is not for everyone. But if someone is in the market for very high quality sound, and looks carefully at the available products, and makes good selections for synergistic coupling, a very good result can be obtained. It will not be real deep in the bass, nor very loud, but it can get pretty loud.
This SPL and deep bass response thing is a big hurdle to overcome. It's like these are the only things that mean anything to some people. If it won't do 20Hz in the bass, people think it is not worthy of consideration. If it can't shake the house, it's no good. So they buy things that have these capabilities, but sound like there is a blanket over the speaker. It is more often than not, a big muffled thud and sizzle, like the home version of one of these modern car audio systems.
Most people who heard a SET system for the first time would have their jaws drop. They would all-of-a-sudden stop thinking about 20Hz extension and 115db SPL.
They would finally be hearing music instead of hi-fi. Funny as it may sound, I really don't think that alot of audiophiles even know what can be achieved with an audio system. (Ducking the tomatoes and running for cover!) Most are satisfied with what they can easily get at the local emporium, that got a good review. Then they think they have about as good as it gets. Natural way of thinking, but not correct.
There is no free lunch, and you don't get a free lunch with SETs either. What you do with SETs, is you forget about the Hi-Fi stuff, and get a healthy dose of music. It's not about bass response. It's not about SPL. It's not about fireworks. It's about music. As crystal clear and clean as you can get. When you start in with trying to get all the Hi-Fi hijinks, then you move away from the music to get it.
The crying shame about electrostatic speakers is that you have to have high power to drive them, and you have to get a veiled amp as a result. Oh, I know, people don't think they have a veiled amp. Listen to a SET on single drivers and you'll find out how veiled a high power amp is.
Up until now, SETs have always had a hard time with extension, because of transformer limitations. But that is now no longer the case. OTL has come to SET amplification, and full frequency extension is possible now with SETs. But the really costly SETs, with excellent iron can do a pretty good job of extension too.
I'd say that SETs are for the real musical enthusiast, or the advanced listener. They are not for readers of audio magazines, and car stereo types. This is also why SET users are almost exclusively analog users. They are after what is beyond the reach of typical gear. |
I love SET and OTL amps. I believe it will be a very long time before I would consider a SS amp. But who knows what tomorrow will bring. I have thought of myself as the king of the tube snobs. I must now pass the crown to Twl. Unless i misunderstood Twl's last four sentences, there are very few audio enthusiasts among the many Audiogon members.
I guess if you own SS amps and a CDP, many of you can't be advanced listeners. arrogance or truth? Either way, Quite a bold statement. I understand Twl's passion. I even agree with much of what he has said. But I find the last four sentences a bit offensive. But he has every right to express his thoughts just as I do. I admire your passion Twl. |
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. :-) |
