Giving up on Power Race, and going SET?

I have never went after power. I am not sure if it was a money thing or a matter of not understanding why would anyone need more power. To me it was a matter of matching equipment and being happy with the sound. The fun was the ability to always change. Sometimes move up, sometimes move sideways.

I fouind some old speakers in my basement and decided to order some Lowther and Fostex drivers to try my hand at making something. If I come close, then I will turn to those who do it everyday and see where I end up.

I do like horns and SETS. The Avantgarde Solo is a surprise and affordable. At 7K most of use would have already gone beyond with amps, wires and speakers. The Solo is an all in one kit...but that's too easy isn't it? Add some interconnects intended for the microwave industry (cheap, good sounding wire) between a CD player with a volume control and the Solos, and you are all set.

Yes, it makes sense to look at this option and leave the power race.

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.