Correlation between sample rate and audible frequency?

[Blumlein 88]

This is my recreation of Earthworks spark discharge calibration for a very good 21mm electret microphone with fairly flat to >20k response. This is essentially a shock wave which no ordinary percussion instrument could produce. The math is a little complex, if anyone wants a reference to the exact shape you can ask it is not of general interest. The point is (virtually) no pre-ringing at 24/48k

Your image reminds me I'm still mad that Adobe didn't honor my CoolEdit licence when they gobbled up CoolEdit.

 

[scott wurcer]

Your image reminds me I'm still mad that Adobe didn't honor my CoolEdit licence when they gobbled up CoolEdit.

You mean they didn't give you an upgrade to Audition? Cooledit is one of 2 or 3 shareware apps that I ever paid for and it still runs under Win10. My wife bought me an Audition 1.5 license when she was a grad student, I have nothing to do with the current cloud based apps.

 

[Blumlein 88]

You mean they didn't give you an upgrade to Audition? Cooledit is one of 2 or 3 shareware apps that I ever paid for and it still runs under Win10. My wife bought me an Audition 1.5 license when she was a grad student, I have nothing to do with the current cloud based apps.

No, they never agreed to an upgrade to Audition. I would have needed to buy it all again. Of course now it is cloud based as you mention.

 

[milezone]

An analog signal is always bandwidth limited, so it does not contain an infinite number of overtones.

What's the limiting factor? Friction? I don't think I could wrap my head around the math version.

 

[Julf]

Did you stomp your foot as well to provide the full effect? The foot stomp is everything...

Nah, usually a suitably haughty smirk is enough.

 

[Julf]

What's the limiting factor? Friction? I don't think I could wrap my head around the math version.

Mostly inertia, unless you also have infinite energy/force.

 

[Pluto]

That's harder to do than it sounds

What you have written does make sense, but the phrase that I was really not getting was...

For real signals, which are not symmetric in time, this means that you cannot perfectly reconstruct signals up to fs/2

When you say "up to Fs/2", I assume you mean "right up to an infinitesimally small amount below Fs/2"? This is not an issue, in the real world, that has ever given me cause for concern in either practice or theory. I know some audiopiles have this thing about the "importance" of harmonics that, supposedly, extend beyond 40kHz but I have never seen or heard any evidence to support this. And even if such harmonics do exist, they will be at low enough a level so as to be entirely masked by lower frequency content at far higher levels*. Most music contains so little energy beyond 16 or 17kHz as to be totally irrelevant to the overall effect. I have never heard a difference in anything by placing a 20kHz third order low pass filter in line.

I often think of digital audio as one of those few areas where we really do get a (nearly) free lunch. It is unfortunate that an awful lot of digital technology is counter-intuitive so doesn't make its supreme elegance sufficiently obvious to those too deaf to hear.

* I sometimes wonder what type of music is required to hear the supposed benefit of these ultrasonic harmonics. A concerto for solo cymbal perhaps?

 

[Fluffy]

* I sometimes wonder what type of music is required to hear the supposed benefit of these ultrasonic harmonics. A concerto for solo cymbal perhaps?

Here you go

 

[Pluto]

Concerto for dustbin lids!

Musically fascinating, up to a point. I liked the pedal-struck gong!

It would be interesting to study the spectrum of this via a very wide bandwidth microphone. The overhead mics we can see look like Audio Technica 4033 to me which are very good but do have a rather over enthusiastic HF end.

 

[Frank Dernie]

Luckily none of the music I listen to contains a half cycle at 22.05 Hz so ringing isn't a problem for me.
As far as hearing ultrasonic frequencies is concerned I did extensive testing about 20 years ago, when my hearing was probably better than it is now and could not hear the addition of a super tweeter to my system on any of the music we tried. The friend who designed the prototype felt he could perhaps hear a tiny difference but not on much music. It was not statistically significant anyway. The super tweeters measured very well I still have them (they didn't go into production) but they are in storage.

 

[pma]

176 khz recording of cymbal hit very hard once with drum stick. Notice how it starts at low level and builds. That is because it takes a finite time for the energy to travel across the metal of the cymbal, reflect from the edge, and build to a resonance at higher level. So even hard struck cymbals are NOT like a Dirac pulse thru the ADC/DAC.

An Earthworks wide bandwidth microphone was used for the recording.

@Ultima Thule prepared a test at diyaudio, cymbal at 176kHz and resampled to 44.1kHz. I have noticed it just a while ago and got 9/10 ABX result, with a valid protocol. Only one attempt, no cherry picking. So there is probably something.

https://www.diyaudio.com/forums/eve...ampling-rates-listening-test-post6040288.html

 

[Julf]

@Ultima Thule prepared a test at diyaudio, cymbal at 176kHz and resampled to 44.1kHz. I have noticed it just a while ago and got 9/10 ABX result, with a valid protocol. Only one attempt, no cherry picking. So there is probably something.

https://www.diyaudio.com/forums/eve...ampling-rates-listening-test-post6040288.html

If I understand correctly, not only did he resample, but he converted it to 320kbs MP3 and back. So we have downsampling-encoding-decoding-upsampling. Any of those steps can introduce audible artifacts that have nothing to do with audibility of ultrasonic frequencies. It also seems no-one got even all 3 out of 3 right. There were only 2 x 3 samples, so to get a 9/10 result, did you use something like the ABX plugin of foobar2000 to run the test?

 

[Blumlein 88]

I could ABX Arny's old jangling keys sample in Foobar. I couldn't figure out why or what I was able to hear. I then resampled his original high rate file with a recent better resampling software, and could no longer hear a difference. Apparently was hearing the resampler.

I'd expect in this case with resampling to MP3 on those files, and back you could hear it.

One of the more interesting cases I've seen was a test by Amandine Pras. Using young listeners, all quality gear, and minimalistic recordings. Everything was concurrently recorded at both 88 and 44 rates. Testing was done 88 vs 44, and 88 vs 88 resampled to 44. A very positive result for a difference between 88 and resampled 88 to 44. Just about 50/50 with native 88 vs native 44. The resampler was the best Izotope software. I'd like to know what it was that made that discernible.

 

[Julf]

One of the more interesting cases I've seen was a test by Amandine Pras. Using young listeners, all quality gear, and minimalistic recordings. Everything was concurrently recorded at both 88 and 44 rates. Testing was done 88 vs 44, and 88 vs 88 resampled to 44. A very positive result for a difference between 88 and resampled 88 to 44. Just about 50/50 with native 88 vs native 44. The resampler was the best Izotope software. I'd like to know what it was that made that discernible.

Any links?

 

[Blumlein 88]

Any links?

https://www.researchgate.net/publication/257068631_Sampling_Rate_Discrimination_441_kHz_vs_882_kHz

You can download the PDF here.

Or if you have a Google account here.
https://www.academia.edu/441305/Sampling_Rate_Discrimination_44.1_KHz_Vs._88.2_KHz

Check your conversation (PM) box.

 

[pma]

If I understand correctly, not only did he resample, but he converted it to 320kbs MP3 and back. So we have downsampling-encoding-decoding-upsampling. Any of those steps can introduce audible artifacts that have nothing to do with audibility of ultrasonic frequencies. It also seems no-one got even all 3 out of 3 right. There were only 2 x 3 samples, so to get a 9/10 result, did you use something like the ABX plugin of foobar2000 to run the test?

Yes I used the foobar ABX.

foo_abx 2.0.2 report
foobar2000 v1.4.8
2020-01-11 09:45:22

File A: A1.wav
SHA1: 0259aa4b0bbbcc86942433499f830ab30cbf9ae4
File B: A2.wav
SHA1: b9bf6f75526deee8f443fd421c3eeb0417bf2c3b

Used DSPs:
Resampler (PPHS)

Output:
ASIO : Creative Sound Blaster ASIO
Crossfading: NO

09:45:22 : Test started.
09:45:42 : 01/01
09:45:49 : 02/02
09:45:56 : 03/03
09:46:03 : 04/04
09:46:10 : 05/05
09:46:17 : 06/06
09:46:23 : 07/07
09:46:29 : 08/08
09:46:35 : 08/09
09:46:41 : 09/10
09:46:41 : Test finished.

 ----------
Total: 9/10
Probability that you were guessing: 1.1%

 -- signature --
3e7905410faaa98110784f1e2100b3edf156916d

I ran only one trial, after listening about 2x to the samples. I am not sure how he prepared them, however below are the spectra. A1 is the truncated one.

 

[bennetng]

Also this:
https://hydrogenaud.io/index.php?topic=110058.0

 

[Julf]

https://www.researchgate.net/publication/257068631_Sampling_Rate_Discrimination_441_kHz_vs_882_kHz

You can download the PDF here.

Or if you have a Google account here.
https://www.academia.edu/441305/Sampling_Rate_Discrimination_44.1_KHz_Vs._88.2_KHz

Check your conversation (PM) box.

Thanks!

 

[Julf]

Yes I used the foobar ABX.

Thanks!

Used DSPs:
Resampler (PPHS)

Was the 44.1/mp3 sample already upsampled to 88.2, or did foobar do the resampling?

 

[pma]

The test files, both, are in 176kHz. I asio and my card runs at 96kHz, so I must turn on foobar resampler, ultra option. Spectral cleanliness verified.