For those of us who enjoy listening at high volumes, but want a relatively compact, easy to place speaker, I'm not sure there is any choice other than to go dynamic drivers/higher power, and ditto for those who prefer panel speakers. In fact, that's basically my whole concern about low power: it's not the simple, flea-powered amps that bother me in theory, it's how you're limited in the speaker department. I've only ever heard some SET systems playing in a store in passing, and haven't ever really auditioned one. But I have a hard time believing that - outside of large horns (which may have other problems, but what doesn't?) - high-SPL, wide-bandwidth, uncolored, non-resonant performance will be available from an easy-to-drive and easy-to-control ultra-high-efficiency speaker. The laws of physics are against it happening, so I assume that folks happy with their SET systems must be giving up some combination of volume, headroom, extension, neutrality, or clean decay behavior to get their special kicks (some of which are always subject to the suspicion of increased, but pleasing, low-order distortion-induced euphony). I've not properly auditioned Avant-Gardes or the like, and don't have anything against increased efficiency where possible, but it otherwise seems to me that the world's most competent speakers still demand something in the way of clean power to sound most like live music, and I for one am not ready to simply view this as a wattage 'rat-race'. I would love to be proved wrong, and have someone play me a bandwidth- and volume-unlimited SET system that sounds accurate while kicking out the live jams at a handful of watts, but I don't know that I'll ever have the opportunity (or that the speakers needed would fit my house/budget), so I'll stay with what I know works reasonably well. |
Zaikesman, I understand and agree with much you have said. Finding a speaker that will give you the desired volume has been hard to find. The flea sized amps that I have heard or owned have had no problem with extension, neutrality, or clean decay. I know there are many SET and OTLs that are euphonic. I would not waste my money on an amp that is colored toward a dark, euphonic, poor extension, or lack of clean decay. There are several SET and OTL amps that do not fit this discription. But you are right, finding a speaker for these kind of amps is very limited. This is what is so frustrating for me. It is hard to argue with many of your view points. But once you hear what these flea sized amps can do with the appropriate speakers, maybe, just maybe, you will understand why people like myself love these flea sized amps. |
I can pull off 105db peaks with my 2 watts, on my Lowther EX3 Voigt Pipes. I can also get right down to 40Hz without the weaknesses that are normally associated with Lowthers, due to my cabinet mods. Yes, they have limitations in the lowest octave.
So for my use, this SPL and bass response is totally adequate in my 24'x14' room with a 16' vaulted ceiling. Add to that, that these speakers make most $25k speakers sound like they have a blanket over them, and that makes you a little more forgiving if there is a little coloration here or there.
As for the "euphonic distortion", I've got to address this, because I am getting really tired of hearing that. First, all SET amps have a specific distortion profile that puts nearly all of its total harmonic distortion into one area of 2nd Order harmonics. Generally less than 1% total. Single driver speakers also have a distortion profile where their total harmonic distortion is mostly in the 2nd Order, and in the case of Lowthers, slightly less than 1%.
Now, since these amps and speakers have this particular relationship in their distortion profiles, their distortions will either be additive, or subtractive, based upon where they line up in terms of phase angle. If the amp distortion profile is 180 degrees out of phase with the speaker distortion profile, the amp AND speaker distortions will largely be cancelled, and provide a lower SYSTEM distortion than ANY other combination of amp/speaker. If they are not 180 degrees out, then reversing the speaker leads will put them 180 degrees out. Even if they fall in between 0 and 180 degrees, there is a medium level of distortion cancellation to be had. This is something that is not available to ANY other amp/speaker combination, and is the reason for the SET/Single-driver synergy that can provide lower SYSTEM distortion than anything else that can be put together regardless of price, because this combination actually causes a self-cancelling of distortion between the speaker and amp, in real time, during music playback. Not just on a lab bench.
Any time that you go to a push-pull, or SS amp, or multi driver speakers with crossover, you have distortion profiles that are spread out all across the harmonic spectrum in varying amounts, that do not lend themselves to this distortion cancelling synergy. This is why total SYSTEM distortion in all other systems is always additive. And has distortion components in the odd-orders that are unpleasant.
So next time you guys want to talk about "euphonic distortion" with SET amps, think about the fact that the "euphonic distortion" is kicking the living hell out of your amp/speaker combination's distortion profile, and makes it look like a distortion generator in comparison.
If you want to find out more about this phenomenon, there are treatises written about it on the web. That's where I found out about it a long time ago. |
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.
|
