John Curl's Blowtorch preamplifier part II

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I had an intern two summers ago rebuilding a pair of Langevin vacuum tube amps. He was playing his MP3 player through them. I did not see the source and assumed he was using the test rack CD player. The sound quality was bad enough I thought there was still something wrong with the amps. So not knowing the source I could hear the lack of quality. Yes those were 320kbs MP3s.

So I suspect I can tell the difference without peeking.

And it couldn't possibly have had anything to do with the quality of his MP3 player?

se
 
I fail to see what makes a difference between the way of choosing musical instruments and choosing loudspeakers, or amplification, to sound system.

I fail to see why a musician can be trusted to choose a musical instrument by sighted listening tests, according to his appreciation of the sound of the musical instrument, while audiophiles cannot be trusted to choose audio gear according to how it sounds to them, sighted.

Then I fail to trust you to design a test. You seem to abhor the thought of minimizing variables as if they don't matter.
 
Audibility of any differences caused by lossy codecs are HIGHLY program material dependant.

Very important point! When I did a blind test of lossy CODECs, I had no problem hearing the differences with a modern digital recording of a female singer (hated the music, but the recording was clean, quiet, and superbly defined) and ranking them in correct order.

My responses to an old analog recording (Dave Brubeck, if memory serves) were totally random. One more data point that convinced me that the old technology was terribly limited.
 
And it couldn't possibly have had anything to do with the quality of his MP3 player?

se

Not in your test spec's! It is hard to put into words what disturbed me. It was not quite what I would call distortion and had it been a modern amplifier whose problems I have more experience with I would not started with the assumption the amplifier had a problem. What I heard was closer to bad compressor pumping than say crossover distortion.

Then again my test rack CD player ain't exactly new.

Also when J.J. stopped by my guys offered to do him in as he had done to music reproduction.

Now Steve I know this may come as a total shock to you, but it is possible that different recording medias have different limitations and thus sound different. I think there may have been a discussion of this around somewhere. :) !
 
I failed to see you stating the difference, to your view, between musicians and audiophiles.

Then you don't want to see. The sound of an instrument is highly variable on the skill of the musician, his familiarity with that instrument, and his inate ability to extract the best out of that instrument based upon how it "fits" him. Tell me there's no extra variables in that scenario.
 
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[snip]Indeed, our experiences are given to bias of expectations, the "Placebo Effect".
Yet, people with integrity, or inner honesty, can neutralize the bias of expectations.[snip].

This is incorrect Joshua. Even being fully aware of the placebo effect, and trying hard not to let it influence you, you still are influenced.
It has nothing to do with honesty or integrity. It's the way we are wired.
This has been shown time and time again.

IF you are interested in circumventing the placebo effect, the only known way is to make sure you hide any information that is not part of whatever you are testing. That is the reason that for all serious, important testing, you can't get around a controlled test in some way.
It's a matter of life and death in medicine; it's not for audio, but the principle is the same.

jan didden
 
Drawing parallels between hearing and taste, sight and touch is perilous. We can extend sensations of sight, taste and touch. We can roll the tasty substance around in our mouths, extend the touch, maintain the gaze.

Can't do it with hearing: It goes past. The best we can do with hearing is to repeat, And it goes past again, just as fast as the first time.

Time frame for the subject has to be longer and opportunity for repetition greater than for testing taste or touch.

It takes me months to figure out what's right and wrong about new speakers. (I live a high noise environment so electronic gear isn't very relevant to me as long as it's reasonable quality). MP3 codecs, as Howard pointed out are vulnerable to classical music, I find. Although describing the difference in words is hard - it's sort of "skinnied down".

I downloaded this yesterday and it actually sounds pertty good but not quite right.

http://www.emusic.com/album/The-Fai...-Haydn-The-Seasons-MP3-Download/11581721.html
 
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I just think a blind test needs to be done over a extended period of time. If you change the conditions in which a person is used to listening ( i.e. hide the components ) it changes how we hear [snip].

Not at all. Your ear doesn't change, the air vibrations don't change when you put a curtain before the amps. What DOES change is your perception, and that's the crux.
All of a sudden your poor brain doesn't see the amps, doesn't have all the other inputs, and only has the sound to rely on. And that's when it discovers that it can't decide on a difference based on the sound alone, when before, with all the help from the other senses, it could.

jan didden
 
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Not at all. Your ear doesn't change, the air vibrations don't change when you put a curtain before the amps. What DOES change is your perception, and that's the crux.
All of a sudden your poor brain doesn't see the amps, doesn't have all the other inputs, and only has the sound to rely on. And that's when it discovers that it can't decide on a difference based on the sound alone, when before, with all the help from the other senses, it could.

jan didden


That's not correct. I think you got to learn the sounds without any preconceived bias to conduct a good blind test. Then test yourself under the same conditions. How we respond to sounds is dependent on the conditions.

Some sounds we don't respond to at all just because they are familiar sounds we hear all the time and have no special significance. These sounds are filtered out. But, we do respond to sounds with special importance.

If you lost your sight how long would it take you to learn echolocation? Should be easy right off the bat according to statement above. Either you hear these differences blind or you don't. In your oppinion these differences don't exist.

Yet some blind people do learn echolocation to navigate their world.

John
 
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That's not correct. I think you got to learn the sounds without any preconceived bias to conduct a good blind test. Then test yourself under the same conditions. How we respond to sounds is dependent on the conditions.

Some sounds we don't respond to at all just because they are familiar sounds we hear all the time and have no special significance. These sounds are filtered out. But, we do respond to sounds with special importance.

If you lost your sight how long would it take you to learn echolocation? Should be easy right off the bat according to statement above. Either you hear these differences blind or you don't. In your oppinion these differences don't exist.

Yet some blind people do learn echolocation to navigate their world.

John

John I'm not sure I understand you here. I don't deny that any differences exist. Maybe I wasn't too clear here. I was giving an explanation for those cases where people are convinced they hear an audible difference that 'disappears' when the curtain is pulled in front of the amps.

jan didden
 
John I'm not sure I understand you here. I don't deny that any differences exist. Maybe I wasn't too clear here. I was giving an explanation for those cases where people are convinced they hear an audible difference that 'disappears' when the curtain is pulled in front of the amps.

jan didden

I just think if you want to do good on a blind test you need practice. You change the conditions - you change the test. Like you say we rely on a lot of information when processing sound.

When I took examines in school, if I just read the book and worked out examples with all the answers in front of me I wouldn't do very good. I'd take practice tests to make sure I really understood the information.

People talk like blind testing should be easy if you there really is a difference. I see it as a pretty difficult test, one you have to practice for.

Obviously some differences are easier to hear than others.

I just think people would do better on a blind test, with practicing blind. I don't know the best way to go about it, maybe it's different for different people.

But, I'd take away any information about the equipment under test while evaluating them. Like just have ( sound A and sound B ) that you could switch between and learn the sound over a period of time. Like the buzzing relay I mentioned. You may not hear a difference at first but in time you might, real or not.

Then take the test and see if you can identify these components blind. Anyway, that's just what I'd do and I think it would make a difference. I'll try it out sometime and see what I can hear.
 
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I just think if you want to do good on a blind test you need practice. You change the conditions - you change the test. Like you say we rely on a lot of information when processing sound.

When I took examines in school, if I just read the book and worked out examples with all the answers in front of me I wouldn't do very good. I'd take practice tests to make sure I really understood the information.

People talk like blind testing should be easy if you there really is a difference. I see it as a pretty difficult test, one you have to practice for.

Obviously some differences are easier to hear than others.

I just think people would do better on a blind test, with practicing blind. I don't know the best way to go about it, maybe it's different for different people.

But, I'd take away any information about the equipment under test while evaluating them. Like just have ( sound A and sound B ) that you could switch between and learn the sound over a period of time. Like the buzzing relay I mentioned. You may not hear a difference at first but in time you might, real or not.

Then take the test and see if you can identify these components blind. Anyway, that's just what I'd do and I think it would make a difference. I'll try it out sometime and see what I can hear.

I think that's a pretty sensible way to approach it. Can't disagree with you.

jan didden
 
Then you don't want to see. The sound of an instrument is highly variable on the skill of the musician, his familiarity with that instrument, and his inate ability to extract the best out of that instrument based upon how it "fits" him. Tell me there's no extra variables in that scenario.

With all the skill of the musician, his familiarity with that instrument, and his innate ability to extract the best out of that instrument based upon how it "fits" him – does the sound of the instruments itself matters?
 
This is incorrect Joshua. Even being fully aware of the placebo effect, and trying hard not to let it influence you, you still are influenced.
It has nothing to do with honesty or integrity. It's the way we are wired.
This has been shown time and time again.

How can you seriously say that (that I'm still influenced) without knowing how I neutralize the Placebo Effect? What you write, without knowing the facts, looks like a religious belief.
 
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