Time resolution of digital sampling

[danadam]

15 hours ago, Jud said:

Compare two files, one with a steady tone, the other the same but with a single missing sample at 44.1kHz sample rate. As I understand it volume may need to be reasonably high.

Like this?

 

15 hours ago, PeterSt said:

Suppose I have a normal song of a couple of minutes; now each other second I silence (manipulate the file) one sample (16/44.1).

Like this?

 

If yes then:

15 hours ago, Jud said:

Can you tell which file contains the missing sample?

Yes, listen sine0missing.flac vs sine1missing.flac

 

15 hours ago, PeterSt said:

Would we readily hear that ?

Depending on the definition of "readily", but yes, listen musiclong.flac vs musiclongmissing.flac (it is 15 seconds long instead of minutes, but should be enough for an example)

 

Assuming that is what you both wanted, what is this test supposed to illustrate?

[danadam]

1 hour ago, pkane2001 said:

 

If I were to try Kunchur's methodology, I'd change at least one thing that he got wrong. He didn't level match the filtered and unfiltered signals. Level differences at or just below 0.2dB can still be detected in the audible band, so the results of Kunchur's test are suspect. 

 

He had assumed that level differences below 0.7dB are inaudible. The detection results he reported were more likely caused by the level differences at 7kHz than any ultrasonic content. His test subjects detected differences just at the 0.23dB level. Where the detection was even more consistent and reliable is also where the level differences were greater, so that does cast some doubt on the study conclusion.

Agreed.

Some further reading :-)

https://hydrogenaud.io/index.php?topic=73598.0

and about the level differences specifically at the end of this post and in the next one: https://hydrogenaud.io/index.php?topic=73598.msg701379#msg701379

[danadam]

On 9/30/2020 at 6:22 PM, Jud said:

 

Kunchur I believe comes out at about half the time of previous studies. But the previous studies IIRC identified a limit of about 10ns, Kunchur about 5.

 

4 hours ago, Jud said:

if I recall correctly, other experimenters found a time for minimum noticeable difference between two non-simultaneous signals about double that of Kunchur, about 10ns vs. Kunchur's 5.

Not ns (nanoseconds) but µs or us (microseconds).

[danadam]

4 hours ago, Jud said:

the other experimental work in this area appears to show we can notice timing differences smaller than 1/20,000th of a second.

 

Of course this isn't the same issue as whether we can hear signals above 20kHz

For inter-channel delays there are files generated at 24/192 with n-sample delays between channels and converted to 16/44:

Quote

1 sample delay = 5.2 uSec
2 sample delay = 10.4 uSec
3 sample delay = 15.6 uSec
4 sample delay = 20.8 uSec

...

I was able to ABX the 20us version. There was a guy who was able to ABX the 10us version.

[danadam]

2 hours ago, Don Hills said:

Edit: I think I can come up with special cases where there may be distortion products below 22 KHz. I'll see what I can do with Audacity.

https://forum.cockos.com/showthread.php?t=201868

[danadam]

On 11/3/2020 at 4:27 PM, yamamoto2002 said:

I created animated graph of a square wave, its wave front moving toward left.

I did an impulse some time ago: https://imgur.com/a/KVFOJU1

Quote

A 16 bit, 44.1 kHz file with 33 impulses. Impulses in the right channel (bottom) are exactly 0.5 second apart, while the distance between impulses in the left channel (top) increases by 1.4 microsecond.

The animation skips to each impulse as evidenced by the time bar at the top. The grey waveform is this 16/44 file upsampled 16x. The highlighted area in the middle is 2-samples wide and centers on zero-crossing of the right, "stationary", channel.

imp.all.44.flac.zip