When a Reviewer "likes" something

Swampwalker, I'm basically in your camp. The point you touched on has also been discussed ad nauseum on the Forum, because I personally do not believe in the notion of "faithful sound reproduction." The very term is either an oximoron or a non sequitor.

We all know that recorded music, regardless of medium, is highly engineered. I suspect that one might even be disappointed by a live music performance versus an engineered sound studio recording. But that is a discussion for another day.

But to the point in your post above, I still think it's better to start on a level playing field regardless of how the final presentation sounds. That is, if a speaker is reported to have a flat FR and have a certain acoustic presentation -- if driven by a SS amp -- but not so if using a tube amp, I want to know that before making a buying decision.

Maybe some folks don't care. I freely admit that a speaker that is ruler flat when measured in an anecheoic sound room will likely not be ruler flat when you take it home. BUT, at least I have some comfort in knowing I'm playing on that level playing field.

And for the record, I love my ARC tube gear. I also think my Paradigm S8s are fine speakers. I'm just a tad rattled because I figured out too late what it really means when one says a speaker is "tube friendly" or "SS friendly," or both.

And since this OP is about reviewer reliability, I think this very important issue should be prominently raised in every tech review.

Mapman, yes in the end you're correct. But if there is a really serious electrical incompatibility between an amp and a speaker, you don't get to the ear part.

I don't get it. And it should be pointed out that with all the references to correct speaker/amp matching, and all the proclamations about how one amplification technology is clearly better than another, there isn't a single reference to what it all means as far as actual sound, and THE SOUND OF THE MUSIC. With all due respect to those posters, it seems that you are discussing the superiority of one technology over another only in the abstract. So, because electrical theory says that this or that should be better, it is going to sound more like music? Haven't we learned anything yet?

One poster goes so far as to say that one technology is more natural, but the other is more accurate? Huh? Really? Natural, by definition, IS accurate.
Bifwynne, please correct me if I am mistaken, but it appears from your posts that it was only when you read Karsten's paper that you realized that your tube amp was not a good choice for your speakers. It may be a silly question, but how did they sound before you discovered this fact?

Frogman, first off, the purpose of my posts is not to eschew the superiority of tube versus SS -- technologically or acoustically. Not at all! My posts speak to the issue that one should be mindful about whether a particular speaker is a good electrical fit with a particular type of amp, be it tube, SS, or perhaps both. Period.

As to how I came to this issue, although I don't know dork about EE, I'm a EE/scientist whanna-be. So I read and ask a lot of questions, both publicly on the Forum and privately via e mail. The process for me has been a slow learning curve.

Based on a number of private and public conversations with the EE/engineer geeks, I believe that a really bad electrical match can change the acoustic presentation of what comes out of the speaker. Depending on the degree of mismatch, the speaker might not wind up sounding like the designer intended.

A couple of the Forum techies convinced me to try the 4 ohm taps. Initially, I thought the sound was terrible. The geeks convinced me to hang in there. So I did.

What I think I'm hearing now is a tighter low end FR because the speakers take an impedance dive to 4 ohms below 100 Hz. So the 4 ohm tap is a better impedance match. The damping factor is probably a little higher too.

I'm not sure why or even if the speakers sound less forward than when driven on the 8 ohm tap. It might be that driving them on the 4 ohm tap tames the acoustic response at the 2.2K Hz crossover point where impedance climbs to 28 ohms.

A tube amp would naturally put out less power facing that much impedance; a tube amp is much less affected by the resistive load. See the White Paper. If all that is so, then my tube amp would be putting out more power (watts) at the impedance bump as compared to a tube amp. Ergo, the possibility that the speakers might sound bright and forward.

Perhaps, running the speakers off the 4 ohm taps lessens the power output at 2.2K Hz impedance peak. Not really sure. Got a private e mail into one of my geek buddies to see what he thinks.

I'll tell you this in summary -- regardless of whether I or anyone else likes my speakers more or less on the 4 ohm tap versus the 8 ohm tap, what IS important is that the acoustic presentation is different. And that's the point I'm trying to get at here - electrical matching (or not) affects the acoustic presentation. Frankly, some may like the coloration, and that's a personal choice.

I hope I answered your question.

Audiophile discovers sound effected by impedance matching! Did it take a lot of research to reach that conclusion? Don't mean to be really rude, but that's basic, basic info.

Bifwynne, Your summation of Ralph's paper is pretty much synonymous with what I last posted. In general (a very important qualifier), don't try to drive a 4-ohm speaker with a tube amplifier, unless it is one humongous beast. Especially don't mate an OTL with a nominal 4-ohm speaker. The reason many/most of us (well, not me) are using multi-driver 4-ohm speakers is because they were made possible by the advent of high power SS amplifiers that use gobs of negative feedback to achieve a very low output impedance, necessary to drive a low impedance speaker, and great looking distortion measurements under laboratory conditions. The 70s phenomenon of the hi-power SS amplifier, abetted by the audio magazine industry, started this ball rolling. (Are any of you old enough to remember HP drooling over the Phase Linear 700 amplifier? 700W per channel, THD in the millionths of a percent, blew up on the odd occasion, sound like shit.) You may notice that more sensible speakers are making a small comeback in the market place, e.g., those made by Coincident, Devore, Spendor, and several others, possibly because there are guys with 10W 300B amps that want to listen to them. But the other point of my post is that Raul made an argument pro SS almost entirely on this issue of impedance matching, and it IS an issue with modern speakers but not the only issue to consider when selecting an amp to drive your beloved speakers. In other areas, SS amplifiers have faults not shared by tube amplifiers, e.g., sensitivity to a reactive load. Many SS designs cannot drive complex loads without becoming unstable, and many are generating much more distortion than a comparable tube amp under such conditions, when you're sitting there trying to listen to music. THD measurements are made driving a power resistor, hardly a surrogate for a modern loudspeaker with several capacitors in the crossover and inductive and capacitative drivers to boot. Also, don't be fooled by enormous "Damping Factor" numbers, another myth made live by the reviewers. Damping factor is the ratio between the input Z of the speaker and the output Z of the amplifier. Typically, the speaker value is assigned to be 8 ohms. All you need is a ratio of around 10. Much above that, excessive DF can have a negative sonic effect on bass reproduction. Yet, very high damping factor quotes, sometimes in the 1000s, are a bragging point for SS amplifiers, again parroted by reviewers.

Having said all that, I would be the first to admit that modern SS amplifiers are probably not so guilty of these sins, and the gap between tube and SS has narrowed. I am very interested in the First Watt amplifiers made by Nelson Pass and in the more expensive Pass Labs amps, though I have yet to get an audition of any. Look for SS amps that use no or very little NFB. Look for amps that have lowest distortion measurements at lowest power output, such that distortion increases linearly with power from less than one Watt upwards. The first Watt is the most important Watt. Look for Class A SS amps. Those will be the best sounding, I think.

I think Raul is very sincere. But I, like some others here, go for "I like it". I like it, because I just came back from listening to live music and what I want to hear in my home is something that sounds like what I just heard from a live musician, with the same dynamic range and clarity. For me this hobby should be mostly a pleasure. I happen to think that when I get a glimpse of Nirvana, the system is doing most things correctly. The better it gets, the more of my LPs sound great. Every time I make a change in my electronics designed to reduce distortion, the system sounds a little better. Isn't that a sign that Raul and I are after the same thing but by different methods? Maybe.