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Topic: Various pictures from Arny's posts (Read 51085 times) previous topic - next topic
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Various pictures from Arny's posts

Reply #100
I'd love to have other people try because the results of one listener don't have much weight.

Listening to impulse sounds is pure torture to me. But with volume turned to barely audible level I tested the 27, 15 and 9 sample delay files. Only thing I hear is that the sound source seems to move more towards left the more delay there is. I did a quick test with the single sample delay file too but couldn't notice any change there.

Is there a reason these tests, like the one bandpass posted he made with sox, are using impulses? It's the most horrible sound one can imagine.

Various pictures from Arny's posts

Reply #101
I'd love to have other people try because the results of one listener don't have much weight.

Listening to impulse sounds is pure torture to me. But with volume turned to barely audible level I tested the 27, 15 and 9 sample delay files. Only thing I hear is that the sound source seems to move more towards left the more delay there is. I did a quick test with the single sample delay file too but couldn't notice any change there.


That actually seems pretty good. Thank you!

Quote
Is there a reason these tests, like the one bandpass posted he made with sox, are using impulses? It's the most horrible sound one can imagine.


The reason why we use simple synthetic sounds in tests like these is that we are trying to use signals that are in some sense like some parts of music, but lack the complexity of music that causes so much masking and vastly reduces the ears sensitivity to small differences.

In most cases small differences like these are not heard on an ongoing basis while listening to  music, dialog or drama.

Instead there are Critical Passages where the sounds coincide in a special way, and bang, it becomes noticeable that something is not right.

Finding those Critical Passages can take a lot of time, and so some of us try to short-cut the process by coming up with artificial sounds that based on what we already know about hearing and listening, are in some sense like the natural sounds, and cause the same technical flaws to be audible.

In actual music, we've found that impulsive sounds like castanets can be good for finding flaws like these. Castanets generate impulses that are actually fairly pure, but with some bandpass filtering and ringing tossed in due to the way they are made. They are probably the musical instrument that spawned a lot of tests like these.

Various pictures from Arny's posts

Reply #102
This is a updated/corrected version. The 27 step delay file is designed to be very easy and give you an idea of what to listen to.

[attachment=8333:impulses...rm_4416_.zip]

Test for 5, 7, 9 and 15 step delays were added to put in some more tests between doable and impossible.

The noise floor has been dropped dramatically by simply changing up the order of the last 2 operations.

The 0 sample delay file is your reference file  - compare all other files to it.


Mention of these files on the HA forum yielded 2 downloads, one of which was my test of it.

Mention of these files on the Squeezebox  forum about a week ago yielded 0 downloads.

Mention of these files on the Head Fi forum yielded 5 downloads and it was just yesterday.


Various pictures from Arny's posts

Reply #103
I don't look at those other forums. If anyone beats my ABX score of 2 sample delay discrimination [with a p val. .055]  , let me know. 

  [edit to add.] Considering I did much better than Clark's findings you mentioned, I looked into it. My 10 microsecond level isn't so special.

"The smallest change in the ITD of pure tones detectable by humans

[just noticeable difference (jnd)] is 10–20 microsec (Mills, 1958;

Durlach and Colburn, 1978; Hafter et al., 1979)"

Various pictures from Arny's posts

Reply #104
I don't look at those other forums. If anyone beats my ABX score of 2 sample delay discrimination [with a p val. .055]  , let me know. 

  [edit to add.] Considering I did much better than Clark's findings you mentioned, I looked into it. My 10 microsecond level isn't so special.

"The smallest change in the ITD of pure tones detectable by humans

[just noticeable difference (jnd)] is 10–20 microsec (Mills, 1958;

Durlach and Colburn, 1978; Hafter et al., 1979)"


I am perfectly satisfied if we can reaffirm the classic thresholds of audibility with ABX testing.  How could we expect to do better?

Various pictures from Arny's posts

Reply #105
I am perfectly satisfied if we can reaffirm the classic thresholds of audibility with ABX testing.  How could we expect to do better?


Well in some instances my perception is clearly slight alterations in lateral positioning, just as we would expect, however in other instances I suspect my brain hears the two impulses and reinterprets them as two crests of a wave form, two cycles long in duration, and hears them as slightly different frequencies. [Sort of a singular "thunk" vs "thump/thud" sound.] This second detection method is not what we are testing for, ITD, but I can't stop my brain from using it as a "cheating method" now can I?

Although I can see how using impulses in isolation would be useful to increase sensitivity and discrimination even down to the 10 microsecond level, or so, I fear there may be other things at play such as frequency detection that I'm subconsciously keying on. Listening instead to music or perhaps even better, continuous correlated pink noise, would be a possible solution. [I can't hear a "frequency" to the thump noise when there is no thump!]

I never would have thought it, but I know I can hear ITD even down to the small single digits of milliseconds when listening to correlated pink noise. I'm not sure if I can get down to the microsecond levels but I would be more than glad to try if you post it. To the best of my knowledge using this would cure the issue I'm worrying about.





Various pictures from Arny's posts

Reply #106
That's not cheating, and your brain does combine the "signals" from both ears at some level. Google binaural beats.

Cheers,
David.

Various pictures from Arny's posts

Reply #107
Well I'm not sure if the word is "cheating" however the part of my brain which does traditional ITD analysis and creates a mental picture of lateral sound stage image localization is no longer being used when I switch into frequency analysis mode and the direction the single "thunk" sound seems to come from does not change, just its tonality.

Various pictures from Arny's posts

Reply #108
The physical property that has changed is the ITD. If you can detect the change, you can detect the change. It doesn't matter how your brain is doing it. If it's detected, it's above threshold. If you can't detect it at all, it's below threshold.

IMO

Cheers,
David.

Various pictures from Arny's posts

Reply #109
I see it as an unintentional artifact of his chosen source material. If he instead used correlated pink noise (mono) then there are no pairs of impulses for the listener to mentally combine together to form a telltale  frequency.

Think of that terrible way Clark did it where he moved two speakers forwards and backwards to change the ITD. Terrible! Whenever you have two drivers in the same room their differing spacing will make changes in their comb filtering from differences in the constructive/destructive soundwave summing of the two sources. Who knows if people were keying off of that or what they were supposed to, ITD.


Various pictures from Arny's posts

Reply #110
I agree that what you describe isn't just testing ITD.

However, clicks or tones or noise through headphones is. There may be different thresholds for different stimuli, which is interesting in itself, but it's still fair for a given stimuli.

Cheers,
David.

Various pictures from Arny's posts

Reply #111
I see it as an unintentional artifact of his chosen source material. If he instead used correlated pink noise (mono) then there are no pairs of impulses for the listener to mentally combine together to form a telltale  frequency.

Think of that terrible way Clark did it where he moved two speakers forwards and backwards to change the ITD. Terrible! Whenever you have two drivers in the same room their differing spacing will make changes in their comb filtering from differences in the constructive/destructive soundwave summing of the two sources. Who knows if people were keying off of that or what they were supposed to, ITD.


I talked to Clark about it Tuesday night over pulled pork, and there was only 1 speaker and the delays were introduced electronically.

Various pictures from Arny's posts

Reply #112
How do you test interaural time delay with one speaker? I think you/he are misremembering something.

Various pictures from Arny's posts

Reply #113
How do you test interaural time delay with one speaker? I think you/he are misremembering something.


You don't and that was a signficant difference between our tests.

My test was an inte rpulse time delay test that became a inter aural time delay test when played through headphones.

If one summed the channels of my test, you came close to Clark's tests.

Clark is not exactly a fan of headphones, and he made his living working with speakers.

 

Various pictures from Arny's posts

Reply #114
NEW

24/96 versus 1644 files with more different kinds of musical samples:

[attachment=8364:dac_test...496_dist.flac]

[attachment=8365:dac_test...96_distf.flac]

There are 4 different selections, the first 3 are musical and the last is the usual keys jangling

You can use the ABX plug in in FOOBAR2K to restrict your listening to any part of any of them, so a minimum of 4 different tests are possible.

There is a ultrasonic IM test at the end after the short little audible test tone. Make sure that you can't hear the difference between the 44 and 96 KHz versions. You may have to turn your listening level down a few dB to obtain the desired totally silent results.

Various pictures from Arny's posts

Reply #115
Other than the usual vulnerability of the test tone section (which people like the organic twins will surely exploit without admitting to it)

Code: [Select]
foo_abx 2.0.1 report
foobar2000 v1.3.3
2015-08-03 10:54:15

File A: dac_test_1644_2496_dist.flac
SHA1: d27e428fc69429ed7a22ed3e650a60fed2d6e246
File B: dac_test_2496_distf.flac
SHA1: 79d74a1262091a2ecf707a6e267c2c4a451f0459

Output:
DS : Primary Sound Driver
Crossfading: NO

10:54:15 : Test started.
10:56:50 : 01/01
10:56:55 : 02/02
10:56:59 : 03/03
10:57:08 : 04/04
10:57:12 : 05/05
10:57:16 : 06/06
10:57:19 : 07/07
10:57:23 : 08/08
10:57:27 : 09/09
10:57:30 : 10/10
10:57:30 : Test finished.

 ----------
Total: 10/10
Probability that you were guessing: 0.1%

 -- signature --
470735494f3cca9d6a3c5b21df1fdbc419c0f02e

there's no audible difference.
 


Various pictures from Arny's posts

Reply #116
Other than the usual vulnerability of the test tone section (which people like the organic twins will surely exploit without admitting to it)

Code: [Select]
foo_abx 2.0.1 report
foobar2000 v1.3.3
2015-08-03 10:54:15

File A: dac_test_1644_2496_dist.flac
SHA1: d27e428fc69429ed7a22ed3e650a60fed2d6e246
File B: dac_test_2496_distf.flac
SHA1: 79d74a1262091a2ecf707a6e267c2c4a451f0459

Output:
DS : Primary Sound Driver
Crossfading: NO

10:54:15 : Test started.
10:56:50 : 01/01
10:56:55 : 02/02
10:56:59 : 03/03
10:57:08 : 04/04
10:57:12 : 05/05
10:57:16 : 06/06
10:57:19 : 07/07
10:57:23 : 08/08
10:57:27 : 09/09
10:57:30 : 10/10
10:57:30 : Test finished.

 ----------
Total: 10/10
Probability that you were guessing: 0.1%

 -- signature --
470735494f3cca9d6a3c5b21df1fdbc419c0f02e

there's no audible difference.

????

Looks to me like there was an audible difference and you nailed it.

Where was the audible difference?

Various pictures from Arny's posts

Reply #117
The audible difference was during the test tone sequence. The faint background noise changes.  I guess you could argue it is IM on either my end or your end but boy is it faint.

If you were to prepare two dead silent tracks using the exact same methodology, with no signal at all, this would tell us if the change in noise floor I can pick up on occurs also in the absence of test tones.



Various pictures from Arny's posts

Reply #118
The audible difference was during the test tone sequence. The faint background noise changes.  I guess you could argue it is IM on either my end or your end but boy is it faint.

If you were to prepare two dead silent tracks using the exact same methodology, with no signal at all, this would tell us if the change in noise floor I can pick up on occurs also in the absence of test tones.


I had that problem and addressed it by turning down the playback level a little. 

It looks like your monitoring environment may be faulty.

Two dead silent tracks would seem to shed very little light. They would both be silent. What would cause them to be different?

Various pictures from Arny's posts

Reply #119
I had that problem and addressed it by turning down the playback level a little.    It looks like your monitoring environment may be faulty.


Since your monitoring environment seems to be faulty as well, how is it we know for sure that the problem isn't embedded in the files themselves?


Dead silent tracks would allow me to determine if what I hear is noise or signal distortion. If there is no signal, yet I still hear a difference, then what I'm hearing can't be distortion, it is noise.

Various pictures from Arny's posts

Reply #120
I had that problem and addressed it by turning down the playback level a little.    It looks like your monitoring environment may be faulty.


Since your monitoring environment seems to be faulty as well, how is it we know for sure that the problem isn't embedded in the files themselves?


I was speaking of that particular monitoring environment, not the only monitoring environment that I have. I also have a 20 MHz dual trace oscilloscope to use to visualize clipping.

However, any real world monitoring environment is going to have finite dynamic range, so if the signal is loud enough and there are adequate gain reserves, the headphone amp can be possibly pushed in to clipping.

No matter what means are used to alleviate any problems with the monitoring system test, if they work, then they are fitting and proper.

Quote
Dead silent tracks would allow me to determine if what I hear is noise or signal distortion. If there is no signal, yet I still hear a difference, then what I'm hearing can't be distortion, it is noise.


If the track is dead silent, then there is no signal to stimulate distortion.

Various pictures from Arny's posts

Reply #121
If the track is dead silent, then there is no signal to stimulate distortion.


Excellent. So you agree, if I hear the same audible difference with dead silence then that would eliminate any notion that what causes the audible distinction is general IM. Or for that matter clipping. All I would be comparing is the noise floors. This would interest me, but seeing as generating two such files is a complex, laborious process on your part I can see why you are scoffing at providing them.

Various pictures from Arny's posts

Reply #122
If the track is dead silent, then there is no signal to stimulate distortion.


Excellent. So you agree, if I hear the same audible difference with dead silence then that would eliminate any notion that what causes the audible distinction is general IM. Or for that matter clipping. All I would be comparing is the noise floors. This would interest me, but seeing as generating two such files is a complex, laborious process on your part I can see why you are scoffing at providing them.


Its not too laborious for me to cut to the chase, I think. ;-)

I think this is what you want.

[attachment=8367:digital_..._vs_4416.flac]

The above file is a 24/96 flac file. The first 10 seconds were made by simply generating 24/96 digital black, there is a impulse, and there are 10 seconds of 24/96 digital black downsampled to 16/44 and upsampled back to 24/96.

They should sound the same.  There is no signal so none of the usual forms of nonlinear distortion are involved.

What do you hear?

Various pictures from Arny's posts

Reply #123
But there's no way for me to test it without the potential problem of observer bias. I'm kindly requesting two files, not one, so I can attempt to ABX them against each other, of digital black. Adding impulse noises, keys jangling, or music before or after the 10 second digital black part is fine by me if you insist, however should I successfully distinguish one digital black from the other you'll never know for sure if it was actually by my listening to the music/impulse/keys jangling part that allowed me to distinguish A from B or if it was just a difference in the noise floors. Add the extra content, besides just the digital black part I'll be focusing on, if you wish.

Quote
The above file is a 24/96 flac file. The first 10 seconds were made by simply generating 24/96 digital black, there is a impulse, and there are 10 seconds of 24/96 digital black downsampled to 16/44 and upsampled back to 24/96.


This, for example, will work as one of the two files I'm requesting. I need a second version of this please, which never had any downsampling and then upsampling section: it was kept as 24/96 the entire time. Then I can attempt to ABX the two files. Thanks.

Various pictures from Arny's posts

Reply #124
But there's no way for me to test it without the potential problem of observer bias. I'm kindly requesting two files, not one, so I can attempt to ABX them against each other, of digital black. Adding impulse noises, keys jangling, or music before or after the 10 second digital black part is fine by me if you insist, however should I successfully distinguish one digital black from the other you'll never know for sure if it was actually by my listening to the music/impulse/keys jangling part that allowed me to distinguish A from B or if it was just a difference in the noise floors. Add the extra content, besides just the digital black part I'll be focusing on, if you wish.

Quote
The above file is a 24/96 flac file. The first 10 seconds were made by simply generating 24/96 digital black, there is a impulse, and there are 10 seconds of 24/96 digital black downsampled to 16/44 and upsampled back to 24/96.


This, for example, will work as one of the two files I'm requesting. I need a second version of this please, which never had any downsampling and then upsampling section: it was kept as 24/96 the entire time. Then I can attempt to ABX the two files. Thanks.



OK and since file length of files like these are short or vanishing, they are both now 60 seconds for relaxed ABXing:

[attachment=8368:digital_...ack_2496.flac]  digital black - generated as 2496, not resampled

[attachment=8369:digital_...644_2496.flac]  digital black - generated as 2496, resampled to 1644 and back to 2496.

The actual question is whether one can hear the highly shaped dither.

[attachment=8370:2496_dig..._ds_1644.png]

 
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