Who makes

Hi Bruce,

I would think that he is measuring voltage, since it would be more practical to do that, and since the majority of speakers conform to the voltage paradigm.

BTW, this article may be of interest. It describes the standard simulated loudspeaker load he uses for those measurements.

Best,
-- Al

That there's a "black box" aspect of synergy or a witch's brew of "X" factors going on in an amp that come together (or not) when driving a particular speaker.

To this point, I seem to recall that a while back Al may have posted something in another OP to the effect that the theory may help one identify a amp/speaker combo that MAY (??) work well and conversely MAY (??) not work well. But, and this is a big BUTT (sic), one will not know for sure until he/she tries out the particular amp/speaker combo of interest.

There really isn't a 'witch's brew' unless the designer of the amp really doesn't know what he's doing :)

To the latter question, because of the confusion that exists in the industry, you still have to try things out.

Al, it sounds to me like you got what I was trying to convey. I am wondering if there can be a better term than 'output impedance'...

Thanks again Al. Well ... I'm back from where I started. It seems that one reason, among many others, that my Ref 150 tube amp does a nice job driving my S8s is because the 1040 joule power supply acts "somewhat" like a monster-current SS in its ability to deliver some serious juice when needed. One second, two or three, dunno. It just seems to work.

And Al, after reading the thread running about tube amps and ESLs, if you think I'm gonna climb onto the speaker "merry-go-round" -- forget it. As a practical matter, there are too few B&M stores in my area that would permit meaningful audition opportunities on like gear. In addition, after having read some reviews about so-called super "top-o-the-line" speakers that have stats that look less stellar than the stats for my speakers, I'm just not willing to drink the Kool-Aid.

Thanks as always.

Best

Bruce

Hi Al,

Thanks for the link re the standard simulated speaker load used by JA. I've seen it before. It's a helpful tool which illustrates how an amp's output voltage (??) varies as a function of speaker frequency.

My non-tech anecdotal reaction is that while the simulated load presents roller-coaster impedance and phase angle curves, I surmise that the "simulated speaker" would not be terribly challenging to drive for a well engineered and made amp. This guess is based on a comparison of the companion functions at each attribute's saddle.

Specifically, the impedance load at the negative phase angle saddle between 70 and 150 Hz does not dip lower than 7 ohms. Also notably, the phase angles at the impedance saddle between 100 and 600 Hz ranges from mildly capacitive to mildly inductive.

As stated, I suspect that the simulated loads just described would not give a well designed and manufactured amp a bad day. Uuuhhmm, I wonder if JA would agree to swap my speakers for his simulated speakers. :) LOL

But as I said, I think the simulated speaker exercise is an illustrative and helpful tool that puts a face on the meaning of the numbers.

Cheers,

Bruce