John Curl's Blowtorch preamplifier part II

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Chris, if that's what was taken from what I said, then I apologize. My point was 100x more to the use of one's long term memory to remember a sound, which is useless beyond a doubt. One doesn't need to go far into a google search to find plenty on that.

Please forgive me. I didn't intend my post to point at you. Rather, at the religious zealots that cannot accept any flaws in their chosen test methodologies.

All good fortune,
Chris
 
As a separate issue, I'm personally not so sure that there aren't important things that need long term listening to properly judge.

There may well be, and no-one has argued the contrary. But any such phenomenon, if it exists, can still be tested ears-only. As soon as you peek, your results are useless (except for story-telling and huckstering). That's a function of the basics of how our brains work, and no human is immune.
 
Here's a simple test to show how ridiculous the claim is- while listening, switch between two levels 0.5 dB apart. If you have reasonably good ears, you can detect this. Now try this with 10 minutes between selections. I'll bet you can't tell one from the other.

Yes! But this tests *one* kind of human response. We're complicated critters with lots of different responses. Beware the Procrustean bed of too much (pre)knowledge, 's all I'm sayin'.

All good fortune,
Chris
 
Counterproductive, in fact. Long-term testing means you have taken way too long a time to make the comparison and thus lost the ability to compare with anything remotely close to a non-remodeled memory.

I cannot agree with this. It's a useful conjecture, but needs to be proved in context, and that's difficult. I'm uncertain if you would actually believe this of yourself. I don't of myself, depending greatly on context and import.

Much thanks,
Chris
 
Chris, honestly, no I don't trust my memories to be good enough for details that would need discerning in a comparison. (Speaking long-term as opposed to short-term memory)

I've actually been witness to a couple crimes (not party, thankfully) and even though a thorough testimony wasn't asked at the scene, I went home and wrote down what I saw/experienced immediately. It's very strange to look back on those memories versus what's written--the gist is still in my mind, but I can't remember 90% of the details, and get plenty wrong. This is how our long-term memory appears to work.

For audio comparisons, you have to keep the samples pretty short and as small a switching time as possible or things start getting fuzzy.

I haven't read too far, but I believe this is open access and the introduction hits many of the points I'm trying to make: Auditory Short-Term Memory Behaves Like Visual Short-Term Memory

Edit: okay, the article is less useful than I hoped. Short term visual and short term audio are close in performance. This is the regime we should hang out in. Once we move up to even "working memory", things start breaking down on details.

If I'm wrong, I'm wont to learn.
 
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Hi Daniel. Thanks for the link. I guess my concerns are less with memory, which is fickle to the point of foolishness, and more with judgment, which is difficult. Who will guard the guards? - like that.

To put it another way: must we accept an obviously flawed test methodology because anything else is too difficult? Sometimes, yeah. But sometimes butts get bitten. My interpretation of the current situation is that the difficulties in making a proper test are really serious ones.

"Life is short,
Art is long.
Opportunity fleeting,
Experiment perilous,
And judgment difficult."
-Hippocrates

Much thanks,
Chris
 
Yeah, this is why I try to avoid calling X better than Y, since I generally lack definitive proof, and just enjoy playing with all this stuff (which hits at my ultimate "fun" goal).

In the meantime, I try to be a pain in the rear of those who do try to call X better than Y without any sort of definitive proof. :D
 
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Joined 2005
Actually the subjective testing tends to reinforce long-developed conclusions by many about frequency response and directivity. It's not as if a group of listeners prefers something, which is then used as input to the product development process.

What has been happening more recently is that simulation tools are maturing and do a steadily better job of predicting the loudspeaker's response on axis and the polar pattern, and physical models are then measured in the anechoic chamber with a sophisticated system, the so-called Spinorama. Out of this one develops a product which is then verified in the subjective testing.

If a competitor's speaker did anomalously well in subjective testing and didn't look very good in the Spinorama, this would be of great interest. So would the reverse situation. Where it got interesting was when the sighted tests showed a large effect that tended to raise the score of the large and attractive speakers compared to the smaller and less-impressive-looking ones.

Actually, the anomalous results tend to come most when professional audio reviewers are used. I don't know offhand what the correlation is with their many-times idiosyncratic hearing (all are subjected to a standard hearing test), but in addition to having rather odd preferences in many cases, the scatter in the data is also generally larger.
 
But with what source? a phone cartridge/TT/Tone arm... which ones? No. I, basically, played my own master R to R tapes thru an inverse RIAA network of great precision and accuracy and listened to the phono stage that way. THx-RNMarsh
I wouldn't be surprised. Probably others also thought of it. I dont know when i thought of it. It is a very good idea IMO and help a lot if you made those recordings yourself.... you know what it is 'supposed' to sound like. You can compare the sound thru the RIAA stage with that source going directly to the line stage/PA.

THx-RNMarsh
I have lp's that Kevin Gray mastered since he started Cohearent. I have taken my preamp to his mastering room and listened to those LP's there on his lathe through his tri-amped, wickedly flat room. Of course, he pulls out some of his test cuts too.

The next best thing
 
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I'm personally not so sure that there aren't important things that need long term listening to properly judge.

There is currently a new thread where XRK posted sound clips of 5 amplifiers. From these 5 amps, 2 are outliers (FH9 and Quasi HEX-BJT) for obvious reasons.

For me it is obvious that FH9 is my least favorite. But the current feedback, singleton input, quasi HEXFET-BJT is so "different". ABXing this clip is very easy because it is different. But this difference mostly in favor of the amp!

In real life, my preference is not decided by things that I hear when I ABXed the file. In real life, my preference is decided by something else. Something that I don't use (and probably can't be used) in ABX...

It's the "general feeling". A feeling that I'm not interested with the sound...

Of course, with experience and knowledge such feeling can be described more scientifically. But the point is (to support others who have post about this)...

What you hear in real life to decide if an amp is better than others might not be what you can hear easily in an ABX.

I think this is all simple. And anyone shouldn't assume that things are complex simply because he doesn't know about the things.
 
Here's a simple test to show how ridiculous the claim is- while listening, switch between two levels 0.5 dB apart. If you have reasonably good ears, you can detect this. Now try this with 10 minutes between selections. I'll bet you can't tell one from the other.
:rolleyes: This is very telling about you. Because this has nothing to do with listening to/evaluating tonal and harmonic content of sound reproduction. Total gain is one of those more gross evaluations verified by even just a fluke meter.
 
I get the feeling that this ABX stuff, as academically important as it is, is being used by many as a replacement for repeated, long term, listening and experiencing of the real thing.

I'm not talking about attending a few live performances a year. I'm talking about decades of immersion in playing and recording music along with the technical aspects of amplifier and speaker design.

You guys harp on JC but he has done about the best one can do at this without actually being a dedicated musician or studio recording engineer for significant portions of his life.

I was lucky in this aspect. I knew by the age of 10, for example what a Rhodes Piano sounded like at my house. at a big venue and on tape.
 
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