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Old 31st January 2013, 04:36 AM   #33871
fas42 is offline fas42  Australia
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Originally Posted by kgrlee View Post
As one of a number of people who have conducted Double Blind Listening Tests on Bandwidth Limitation, I'll remind everyone here that in ALL the reliable tests, those who could tell the difference Double Blind, (ie true golden pinnae who are more sensitive) PREFERRED the Bandwidth Limitation.
My miserable memory tells me that eons ago the same thing happened when attempting to decide on the bandwidth for recording, playback, or something or other. One astute chappy connected the dots, and redid the test with live music, with different acoustic materials in front of the musicians filtering out frequencies. Of course, the "straight" presentation was preferred, and all was saved -- none of the experts who set up the equipment could bring themselves to admit that the system used was stinking with distortion, so of course the audience preferred that which rescued them from the worst excesses ...

To my mind the same is still the case, except the problem is a lot more subtle these days ...

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Old 31st January 2013, 06:35 AM   #33872
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When bandwidth sound reproduction is preferred, something is wrong with the audio system used. This may easily happen and double blind test will reveal it, not fix it.
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Old 31st January 2013, 07:18 AM   #33873
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As one of a number of people who have conducted Double Blind Listening Tests on Bandwidth Limitation, I'll remind everyone here that in ALL the reliable tests, those who could tell the difference Double Blind, (ie true golden pinnae who are more sensitive) PREFERRED the Bandwidth Limitation.
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Originally Posted by fas42 View Post
My miserable memory tells me that eons ago the same thing happened when attempting to decide on the bandgwidth for recording, playback, or something or other. One astute chappy connected the dots, and redid the test with live music, ...
Quote:
When bandwidth sound reproduction is preferred, something is wrong with the audio system used. This may easily happen and double blind test will reveal it, not fix it.
It were Dr. Harry F. Olson - Experiment That Saved Hi-Fi

My experiments were circa 1980 with vinyl & mastertapes from the record companies. I thought I'd gone into all this earlier in this thread.

I'm interested in whether the State of the Art is still at the stage where eg 20kHz brick wall sounds better.

Of course there are those who are uninterested in what sounds better and prefer to have their Golden Pinnae myths unblemished by truth.
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Old 31st January 2013, 08:08 AM   #33874
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He was one of the greatest acoustical engineers ever.
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Old 31st January 2013, 10:56 AM   #33875
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Originally Posted by kgrlee View Post
It were Dr. Harry F. Olson - Experiment That Saved Hi-Fi
Of course there are those who are uninterested in what sounds better and prefer to have their Golden Pinnae myths unblemished by truth.
"But the fact that the listeners preferred full-range sound, if undistorted, had now been proved. "

OMHO, i prefer my speakers without tweeters (horn up to 16KHz, time aligned) but i prefer my electronic as fast as possible, and, as i said, a bandwidth up to 200Khz for my amp, and no brickwall for my CD. Hard to explain.
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Last edited by Esperado; 31st January 2013 at 11:07 AM.
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Old 31st January 2013, 10:59 AM   #33876
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Fas42, i totally disagree. I am sure that, when there is nothing your ears can hear, or your tweeter can reproduce, there is nothing !
If Hf and high order distortion products outside of the bandwidth have some effects we can notice, it is because the IM they produce *inside* our listening window.
It's still an effect of HF distortion.
So, in practice you are not disagreeing

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Well, there is probably something else which can have an influence, it is the slew rate of the signals. Even when the high harmonics of this signal, necessary to make this fast rise, are upper than the limit. Something in relation with instantaneous acoustical power ?
When HF signals are slew limited something ugly happens
You can either filter the hell of it (which introduces phase shifts as low as 1khz), or deal with it (building "fast" amps, like JC does for instance)
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Old 31st January 2013, 11:11 AM   #33877
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Quote:
Originally Posted by kgrlee View Post
As one of a number of people who have conducted Double Blind Listening Tests on Bandwidth Limitation, I'll remind everyone here that in ALL the reliable tests, those who could tell the difference Double Blind, (ie true golden pinnae who are more sensitive) PREFERRED the Bandwidth Limitation.
Like most sane people would prefer not to hear HF distortion, even at the price of loosing some upper harmonics.
The hard thing is to reproduce HF well.

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Originally Posted by kgrlee View Post
It were Dr. Harry F. Olson - Experiment That Saved Hi-Fi

My experiments were circa 1980 with vinyl & mastertapes from the record companies. I thought I'd gone into all this earlier in this thread.
Yes you did, but you talked about the first experiment only a few posts earlier, which is misleading, if someone doesnt also read Olson paper.

Quote:
I'm interested in whether the State of the Art is still at the stage where eg 20kHz brick wall sounds better.
IME, it's better than in the 80s and 90s but still far from good fidelity in most cases.
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Last edited by Telstar; 31st January 2013 at 11:14 AM.
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Old 31st January 2013, 11:32 AM   #33878
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Originally Posted by Esperado View Post
OMHO, i prefer my speakers without tweeters (horn up to 16KHz, time aligned) but i prefer my electronic as fast as possible, and, as i said, a bandwidth up to 200Khz for my amp, and no brickwall for my CD. Hard to explain.
As many others have stated, it's still hard for digital playback to get the upper frequencies right every time. Not because of any intrinsic problem with sourcing from digital, but because there are so many ways for the sound to go astray. There are many techniques for getting around this, yours is one of them. Mine is to steadily, relentlessly eliminate every weakness in the playback mechanism, and this if pursued sufficiently diligently delivers truly superb sound ...

Frank
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Old 31st January 2013, 12:07 PM   #33879
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Originally Posted by Telstar View Post
It's still an effect of HF distortion.
So, in practice you are not disagreeing
When HF signals are slew limited something ugly happens
You can either filter the hell of it (which introduces phase shifts as low as 1khz), or deal with it (building "fast" amps, like JC does for instance)
I don't know. My actual preamp and power amplifier have 1000V/µs of slew rate, and low IM distortion. I can reasonably suppose they do not produce too much of TIM ?
Really, i cannot explain why i do not like any (good) tweeter. May-be more a question of acoustical coherency due to filters.
Anyway, most of us are too old, here, to can experiment in a useful way: we need young girls to talk about HF limits.
I remember when i was discovering the Grateful Dead's records. Their engineer was a women, and the mixs quite different from men's ones in tonal balance. More basses (because women hear them less) and less treble (because women hear them better ?).

I wonder too why women are less interested in HIFI than men ?
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Last edited by Esperado; 31st January 2013 at 12:21 PM.
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Old 31st January 2013, 12:32 PM   #33880
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I'll remind everyone here that in ALL the reliable tests, those who could tell the difference Double Blind, (ie true golden pinnae who are more sensitive) PREFERRED the Bandwidth Limitation.
My own (humbling) experience exactly. I've written it up here somewhere, but we tried a blind test of an FM multiplex 15kHz filter. Ruler flat to 15kHz, then a steep roll-off of more than 60dB at 19kHz. Lots of phase shift of course.

Of four participants, one stepped out because he admitted not hearing any difference. The remaining three, yours truly among them, all identified correctly the two different situations but inverted: we thought that the situation with the filter switched in sounded the best! We also had similar descriptions of that 'best' situation: brighter, more attack, more transients. As I said, humbling.

I had the Slot book John referred to (no longer, gave it away) but never found that passage.

jan
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Last edited by jan.didden; 31st January 2013 at 12:36 PM.
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