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Various pictures from Arny's posts

Reply #25
You'd love the IM I get on my oldest system here using Arny's sample. At moderate levels, the loudness of the IM is unrelated to the setting of the volume control! At volume=0, it's not there because the audio output is muted, but then between volume=1 and 10 (which is a range between almost inaudible and a reasonable listening level for normal audio signals) the loudness of the IM is pretty much constant.

This volume control is on a crappy Sony mini system which sits between the audio 2496 sound card and the HD 580 headphones.


Would you like me to tell you another secret that I learned a few years back? If you put ultrasonic audio content through something that's also processing analogue SD video, the relationships between the audio, and the harmonics of the video line frequency (15.625kHz, 31.25kHz etc for "PAL"), change the distortion products. Hence, if you don't remember there's also ~15kHz + harmonics already in the system, there will appear to be magic ultrasonic frequencies at which distortion increases and virtually disappears.


With all the facts, these things are quite predictable. Without all the facts, the distortion due to ultrasonic signal components can seem quite random and unpredictable. That's why it's good to see an IMD test signal with several different sets of frequencies in it.

Cheers,
David.

Various pictures from Arny's posts

Reply #26
What output device do you have that doesn't have IM, Wombat?

Today I tested a few more soundcards I have. Realtek ALC1150 built-into the Maximus VI Formula motherboard, Creative Sound Blaster X-Fi Surround 5.1 Pro USB device, Creative Sound Blaster X-Fi HD USB device and Creative Sound Blaster X-Fi Titanium HD PCIe device all failed the test. The Titanium HD first appeared to pass the test but I found with RMAA that it was internally resampling to 48 kHz. Fixing that required installing Creative Console Launcher and with clock set to 96 kHz it failed the test too.
That's 6 tested DACs and none of them passed the test.

Another things to note is that the original sample has intersample peaks exceeding 0 dBFS causing clipping distortion with maximum volume on some of these devices. But lowering volume didn't remove the IM, it just made it quieter and required more attention to hear. Open headphones in an environment with a lot of background noise easily masked it but closed isolating headphones work wonders for hearing such detail.

Various pictures from Arny's posts

Reply #27
I use the X-Fi Xtreme Music PCI in my gaming rig. W7 64 there, using audio modus in the Creative console set to 96kHz and also in the Win control panel. Open HD 590. No IM that i can spot. I never listen to loud and this jangling drives me nuts! Nothing i want to abx for long.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Various pictures from Arny's posts

Reply #28
Would you be so kind to run RMAA test on the device? The X-Fi Titanium HD gets these results at 96 kHz from the headphone output port.
Excuse the nonsense in device field. Seems like the latest RMAA version uses Russian too eagerly.

Various pictures from Arny's posts

Reply #29
I should have checked the specs of that Behringer UCA202 immediately. It's only 48 kHz capable device so it doesn't really quality for this test. You are covered by Windows's excellent resampler and thus free from aliasing and distortion.


I certainly hope everyone is doing an RMAA test of their device's output under the conditions they will be using it (e.g. same software settings and windows output APIs) before they do high frequency or ultrasound testing.  If not, you really have no idea exactly what is being output.

Various pictures from Arny's posts

Reply #30
Would you be so kind to run RMAA test on the device? The X-Fi Titanium HD gets these results at 96 kHz from the headphone output port.
Excuse the nonsense in device field. Seems like the latest RMAA version uses Russian too eagerly.

I did some when reording my nvidia VGA cards a while back and it was ok but 48khz only. No interest atm for more.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Various pictures from Arny's posts

Reply #31
No IM but the unfiltered version has a tiny click at the very end, so 3 while i hear only 2 with the filtered.
Good call. I hear that extra click at the end too: a dead obvious tell. [I think there is actually a click at the end of both but on one of them it is prominent, like the preceeding clicks, and on the other one it very faint.]

I'm now using HDMI out [I'm not a jitterphobe] at 96k to my prepro which verifies that the incoming signal is indeed 96, but I'm still plagued with faint IM.

Various pictures from Arny's posts

Reply #32
Since I have been doing quite a bit of IM testing with Arnold's file I decided to isolate and fix the part I have been using. The attached file has nothing but the ultrasonic signals with smooth fades making it inaudible if there's no distortion.
[attachment=8253:im_test_tones.flac]

While at it I realized I had one more sound card capable of 96 kHz playback - Audioengine D1. Not surprising it failed the test too. Easiest way to prevent these distortions seems to be to let Windows resample everything to 44.1 or 48 kHz.

Various pictures from Arny's posts

Reply #33
Arnold, I tested the keys_jangling_full_band_2496_test_tones_f4.flac with ODAC and Xonar Phoebus soundcards using three different headphones (KRK KNS-8400, Sennheiser HD 650 and AKG K601) and I heard a quiet high frequency tone in the IM parts with each setup with moderately loud volume. All these devices should perform quite nicely yet they all fail the IM part. I'm curious to know what kind of hardware does not.

Edit: ran RMAA tests on the soundcards in question. Xonar Phoebus headphone output @ 96 kHz and ODAC into Xonar @ 96 kHz


I have noticed similar results with the Realtek ALC887 8-Channel High Definition Audio CODEC on the M5A97 II system board on this system.  I have other audio interfaces and headphone preamps which I will attempt to test shortly.

The test tones at > 30 KHz are a more severe test than any pre-packaged test scheme such as the Audio Rightmark, that I know of.  Not to fault good software because I think the Rightmark tests are just fine.

This whole test is basically very severe to the point of being irrational, and the levels and frequencies involved in both the keys jangling and test tones are worst case tests that are so severe as to be irrational as well.

Your listening test includes, but the RMAA testing does not include any IM that is created by  the headphones themselves.  I know of no known headphone IM testing at these frequencies, either.

This is of course a truism, but without actual acoustical measurements, who knows?  The relevant measurement might be performed with a mic or SPL meter with normal 20-20 KHz response.

The headphones I am using are ATH-M50s and I have other headphones and earphones to test with.

Various pictures from Arny's posts

Reply #34
The attached file has nothing but the ultrasonic signals with smooth fades making it inaudible if there's no distortion.
No more clicks to count, acting as a tell. Good job.

Various pictures from Arny's posts

Reply #35
Your listening test includes, but the RMAA testing does not include any IM that is created by  the headphones themselves.  I know of no known headphone IM testing at these frequencies, either.  This is of course a truism, but without actual acoustical measurements, who knows?


Sure there's IM in the electrical domain,  in transducers, and in the acoustical domain, but what is freaky is there is something akin to IM in the human mind as well. Here's a test which must be listened to on headphones. The left ear gets a pure, undistorted frequency and your right ear gets a slightly different frequency, however these two tones are in different channels so they can't combine to form IM products either in the electrical domain, your headphone driver, nor the acoustical domain, yet we hear a third product in our minds: a binaural beat.

Various pictures from Arny's posts

Reply #36
Your listening test includes, but the RMAA testing does not include any IM that is created by  the headphones themselves.  I know of no known headphone IM testing at these frequencies, either.  This is of course a truism, but without actual acoustical measurements, who knows?


Sure there's IM in the electrical domain,  in transducers, and in the acoustical domain, but what is freaky is there is something akin to IM in the human mind as well. Here's a test which must be listened to on headphones. The left ear gets a pure, undistorted frequency and your right ear gets a slightly different frequency, however these two tones are in different channels so they can't combine to form IM products either in the electrical domain, your headphone driver, nor the acoustical domain, yet we hear a third product in our minds: a binaural beat.


Thanks for the information. So now there are two possible sources of audible IM that the Rightmark program cannot detect. However the test tones in the Keys Jangling test files is identically the same in both channels, so it would appear that binaural beating while  interesting, is irrelevant.

Various pictures from Arny's posts

Reply #37
Thanks for the information. So now there are two possible sources of audible IM that the Rightmark program cannot detect. However the test tones in the Keys Jangling test files is identically the same in both channels, so it would appear that binaural beating while  interesting, is irrelevant.


Well that and its presumed that you can hear the primary frequencies in a binaural test.  If its ultrasound, then the IMD has to happen somewhere earlier in the chain.

Various pictures from Arny's posts

Reply #38
What's interesting about the binaural beat demo I linked to is it proves that in at least this particular instance, this extra sound, the "IM product" for lack of a better term, can't possibly be due to one's electronics, the transducers, etc.: it MUST be in the mind. My point though is that I believe there is also "perceived IM product" from dual tones* when presented to the SAME ear, created by the mind, however it is much more difficult to demonstrate this conclusively because we can't be 100% certain it isn't simply inherent to the signal which arrives at the ear drum, either due to, for instance, the IM of one's electronics or the IM of one's headphone driver, like we CAN be certain of in the binaural beats demo].

*Even from dual tones which are themselves ultrasonic!? Yikes! Hmm, that would be pretty freaky, I admit, but not impossible since we don't have a clear understanding of what causes the binaural beat phenomenon.

---

Why did you build in this IM test into your keys jangling challenge anyways, Arny? Was there some history of ultrasonic sounds causing audible band IM products, thereby contaminating the results, in some previous ultrasonics test? Oh wait, I'm now thinking of that wacky Oohashi (spelling?) guy and how the test that came after his which used alternate transducers for the different frequency bands showed no ability of listeners to differentiate the sounds with the "hypersonics" from the normal versions. Was that what prompted you?

Various pictures from Arny's posts

Reply #39
I have now confirmed that the IM distortion indeed does come from the sound card. I connected the sound card's output to both headphones and line-in at the same time with Y-splitter cable and recorded what the device plays. The output looks like this:


I then used foobar2000 to play the im_test_tones file looped and recorded the output from my headphones with iPhone and Dayton iMM-6 mic. It shows the same signals:


Various pictures from Arny's posts

Reply #40
So as I read it the loudest component of the IM, with Case's soundcard, is 75 to 80 dB down from the test signal, which is itself markedly louder than the average level of the keys jangling. Do we really need to worry if the keys have some faint IM products of their own some 75 to 80 down from their level, especially considering their cacophonous and fairly wide band nature? I'm confident it will be perceptually masked.

If Arny were to release his keys challenge file without ANY test tones tacked on the end, I bet nobody, even me  , will pass the test.

Various pictures from Arny's posts

Reply #41
Since I have been doing quite a bit of IM testing with Arnold's file I decided to isolate and fix the part I have been using. The attached file has nothing but the ultrasonic signals with smooth fades making it inaudible if there's no distortion.
[attachment=8253:im_test_tones.flac]

While at it I realized I had one more sound card capable of 96 kHz playback - Audioengine D1. Not surprising it failed the test too. Easiest way to prevent these distortions seems to be to let Windows resample everything to 44.1 or 48 kHz.


Seems like I need to  honor this worthy effort by including it into a  distributed file collection.

So here you are:

[attachment=8254:keys_jan...tones_f5.flac]

[attachment=8256:keys_jan...tones_f5.flac]

About the test tones. Concerns about high frequency IM have been common to previous published attempts to isolate any possible audible differences due to increases in recording and playback system bandwidth. Loudspeakers with separate amplifiers and loudspeaker drivers for the range > 20 KHz are not uncommon.

It seems like people are more likely to report on audible differences in the test tones segment. This seems reasaonble and useful since it gives insights to the prevalence of audible problems with high frequency IM in real world playback system. But, such results need to be reported clearly and separately from positive results obtained with the actual keys jangling segment.

Based on previous experiments I suspect that spurious responses in the 20-44 KHz can be as small as -60 dB and  positive results may still be reported, but not much smaller.  This amount of nonlinear distortion (equivalent to 0.1% THD) does not seem to me to be an excessively demanding standard for modern audio gear.


Various pictures from Arny's posts

Reply #42
Using my notebook's internal sound card at 96k, at somewhat elevated levels (but NOT clipping the target tone), keying on the IM sound of the test tones, source of IM unknown [which is exactly what the organic twins are probably doing but they won't admit it]:

Code: [Select]

foo_abx 2.0 report
foobar2000 v1.3.3
2015-04-06 20:18:59

File A: keys_jangling_full_band_2496_1644E2Q150_2496_test_tones_f5.flac
SHA1: 0c05bc4a9e99eb72528a4b12c6a2769638f234a0
File B: keys_jangling_full_band_2496_test_tones_f5.flac
SHA1: 1fde9c4e1c933827af0efcdba74cd10d0e2a88f1

Output:
DS : Primary Sound Driver
Crossfading: NO

20:18:59 : Test started.
20:19:31 : 01/01
20:19:36 : 02/02
20:19:43 : 03/03
20:19:47 : 04/04
20:19:51 : 05/05
20:19:57 : 06/06
20:20:01 : 07/07
20:20:06 : 08/08
20:20:06 : Test finished.

 ----------
Total: 8/8
Probability that you were guessing: 0.4%

 -- signature --
0287eb7aa313132ae790c42cd2a8b82d4c9b685d


Using HDMI at 96k to my Marantz prepro in Pure Direct mode, NOT at elevated mode at all, keying on the same IM distortion after the target tone, the difference is so obvious I simply "ran the Xs" and hardly ever even needed to hit A or B to reestablish my reference:

Code: [Select]

foo_abx 2.0 report
foobar2000 v1.3.3
2015-04-06 20:33:37

File A: keys_jangling_full_band_2496_test_tones_f5.flac
SHA1: 1fde9c4e1c933827af0efcdba74cd10d0e2a88f1
File B: keys_jangling_full_band_2496_1644E2Q150_2496_test_tones_f5.flac
SHA1: 0c05bc4a9e99eb72528a4b12c6a2769638f234a0

Output:
DS : Primary Sound Driver
Crossfading: NO

20:33:37 : Test started.
20:34:02 : 01/01
20:34:07 : 02/02
20:34:12 : 03/03
20:34:19 : 04/04
20:34:25 : 05/05
20:34:29 : 06/06
20:34:32 : 07/07
20:34:40 : 08/08
20:34:40 : Test finished.

 ----------
Total: 8/8
Probability that you were guessing: 0.4%

 -- signature --
26523f2037de763acf8946ca2a296939942e0c5c


At least the audible clicks are now gone.

Various pictures from Arny's posts

Reply #43
It seems like people are more likely to report on audible differences in the test tones segment. This seems reasaonble and useful since it gives insights to the prevalence of audible problems with high frequency IM in real world playback system. But, such results need to be reported clearly and separately from positive results obtained with the actual keys jangling segment.


Clearly? Separately? Hear, hear. Yet you insist on gluing the two segments together into one big file instead of keeping the keys test distinct from the IM test. Why?

Quote
Based on previous experiments I suspect that spurious responses in the 20-44 KHz can be as small as -60 dB and  positive results may still be reported, but not much smaller.  This amount of nonlinear distortion (equivalent to 0.1% THD
Incorrect. It may be around -60 dB down from full scale, which is close to where you put the test tones (just a tad below FS), sure, however the keys jangling part which is what we actually hear and we are focusing on (and use to set our playback levels) you recorded some 30 to 40 dB down from full scale, so the net result is that this IM noise we hear from your tones is only 20 to 30 dB down from what we are actually listening to, the keys. And it appears in isolation after the keys so the keys can't mask it, making it dead obvious.

Various pictures from Arny's posts

Reply #44
It seems like people are more likely to report on audible differences in the test tones segment. This seems reasaonble and useful since it gives insights to the prevalence of audible problems with high frequency IM in real world playback system. But, such results need to be reported clearly and separately from positive results obtained with the actual keys jangling segment.


Clearly? Separately? Hear, hear. Yet you insist on gluing the two segments together into one big file instead of keeping the keys test distinct from the IM test. Why?


I think the test tones would be ignored by most if not in the same file.

Quote
Quote

Based on previous experiments I suspect that spurious responses in the 20-44 KHz can be as small as -60 dB and  positive results may still be reported, but not much smaller.  This amount of nonlinear distortion (equivalent to 0.1% THD

Incorrect. It may be around -60 dB down from full scale, which is close to where you put the test tones (just a tad below FS), sure, however the keys jangling part which is what we actually hear and we are focusing on (and use to set our playback levels) you recorded some 30 to 40 dB down from full scale, so the net result is that this IM noise we hear from your tones is only 20 to 30 dB down from what we are actually listening to, the keys. And it appears in isolation after the keys so the keys can't mask it, making it dead obvious.


The peak level of the 24/96 keys jangling segment is very close to FS for me.

Code: [Select]
    Left    Right
Min Sample Value:     -26307.07    -29561.82
Max Sample Value:      25997.06    24536.21
Peak Amplitude:       -1.91 dB    -.89 dB
Possibly Clipped:     0              0
DC Offset:            0              0
Minimum RMS Power:    -72.17 dB    -71.97 dB
Maximum RMS Power:   -16.95 dB    -16.93 dB
Average RMS Power:    -30.03 dB    -29.11 dB
Total RMS Power:    -28.08 dB    -27.17 dB
Actual Bit Depth:        24 Bits        24 Bits

Using RMS Window of 50 ms



Various pictures from Arny's posts

Reply #45
Quote
Quote
Based on previous experiments I suspect that spurious responses in the 20-44 KHz can be as small as -60 dB and  positive results may still be reported, but not much smaller.  This amount of nonlinear distortion (equivalent to 0.1% THD
  Incorrect. It may be around -60 dB down from full scale, which is close to where you put the test tones (just a tad below FS), sure, however the keys jangling part which is what we actually hear and we are focusing on (and use to set our playback levels) you recorded some 30 to 40 dB down from full scale, so the net result is that this IM noise we hear from your tones is only 20 to 30 dB down from what we are actually listening to, the keys. And it appears in isolation after the keys so the keys can't mask it, making it dead obvious.
  The peak level of the 24/96 keys jangling segment is very close to FS for me.


The fleeting dynamic peaks, in this instance lasting for only tiny fractions of a second (and also hard to discern because they are extremely high frequency), may indeed be up there, but the average level which we audibly focus on and use to set our volume knobs for comfortable playback is about 30 dB down from where the steady state IM test tones are recorded.

 
Quote
Code: [Select]
  Average RMS Power:    -30.03 dB    -29.11 dB

Various pictures from Arny's posts

Reply #46
I think the test tones would be ignored by most if not in the same file.


Perhaps you are an optimist and I am a pessimist. You designed the test from the perspective that fellow, scientifically minded people on (for instance) HA will take the test and honestly report if they hear IM, like I think everyone here (including myself now that I'm not resampling down via Windows) reports as having heard, despite trying a wide range of DACs. Me? I would have designed the test without inserting these tells which the organic twins, and their followers, can key on and then pretend "I heard a difference in the keys part. I swear.", which is what they are doing. You can't make a public challenge and tell people "Only concern yourself with the first 12 seconds and don't vote based on what you hear after that". They aren't going to follow that and instead are going to promote their Hi-Re$ mythology and pecuniary interests.

I also suspect that due to the loud, cacophonous, very dynamic nature of the keys' sound that any perception of faint, exceedingly brief moments of IM, which I think occur only on the peaks, is unlikely. Studies which previously have tested using sustained test tones, similar to the ones you used, or other musical instruments, are very different from your keys' extremely brief peaks of ultrasonic content.

My theory that the ultrasonic content plummets if the fleeting peaks where to be removed could be tested by intentionally clipping the signal. If you have the means to do that I bet you'll see it effectively acts as a LPF, removing the ultrasonics.

Hearing faint IM products from your long, sustained test tones, in complete isolation from any other sounds which might mask our perception, is very different from transient IM produced by, and during, the jangling keys.

Various pictures from Arny's posts

Reply #47
Quote
Quote
Based on previous experiments I suspect that spurious responses in the 20-44 KHz can be as small as -60 dB and  positive results may still be reported, but not much smaller.  This amount of nonlinear distortion (equivalent to 0.1% THD
  Incorrect. It may be around -60 dB down from full scale, which is close to where you put the test tones (just a tad below FS), sure, however the keys jangling part which is what we actually hear and we are focusing on (and use to set our playback levels) you recorded some 30 to 40 dB down from full scale, so the net result is that this IM noise we hear from your tones is only 20 to 30 dB down from what we are actually listening to, the keys. And it appears in isolation after the keys so the keys can't mask it, making it dead obvious.
  The peak level of the 24/96 keys jangling segment is very close to FS for me.


The fleeting dynamic peaks, in this instance lasting for only tiny fractions of a second (and also hard to discern because they are extremely high frequency), may indeed be up there, but the average level which we audibly focus on and use to set our volume knobs for comfortable playback is about 30 dB down from where the steady state IM test tones are recorded.

 
Quote
Code: [Select]
  Average RMS Power:    -30.03 dB    -29.11 dB



The keys jangling test signal is highly diagnostic for clipping, and this is an understatement!

Here is a sample with the gain increased 2 dB, clipped at FS and then dropped back by 2 dB, This is clipping of about 1.11 dB which is a tiny amount given that the crest factor of the file which is about 26 dB. The files peak at FS -0.89 dB. According to CEP 2.1 there are only 2 (two) clipped samples in the keys jangling portion of the file which has about 2.4 million samples in it. The file is thus clipped << 0.1% of the time.

[attachment=8257:keys_jan..._clip_f5.flac]

The above file is designed to be compared to:  keys_jangling_full_band_2496_test_tones_f5.flac .

Here is my ABX log - no references to A or B during the test trials, just ran the X's:

Code: [Select]
foo_abx 2.0 beta 4 report
foobar2000 v1.3.5
2015-04-07 15:56:08

File A: keys jangling full band 2496 test tones f5.flac
SHA1: 1fde9c4e1c933827af0efcdba74cd10d0e2a88f1
File B: keys jangling full band 2496 test tones clip f5.flac
SHA1: 6a83beabc4cfd36af05c61ebaddcb20c0daeddca

Output:
DS : Primary Sound Driver

15:56:08 : Test started.
15:56:45 : 01/01
15:56:53 : 02/02
15:56:58 : 03/03
15:57:03 : 04/04
15:57:07 : 05/05
15:57:16 : 06/06
15:57:20 : 07/07
15:57:24 : 08/08
15:57:30 : 09/09
15:57:34 : 10/10
15:57:40 : 11/11
15:57:43 : 12/12
15:57:51 : 13/13
15:57:55 : 14/14
15:58:00 : 15/15
15:58:05 : 16/16
15:58:05 : Test finished.

----------
Total: 16/16
Probability that you were guessing: 0.0%

-- signature --
f1ac1deb470c882991da9006f52010ac6042888d


This was done while listening to just a 2 second segment of the keys jangling file t < 12 seconds. Hint: there are at least 2 different 2 second segments that are equally revealing.

Various pictures from Arny's posts

Reply #48
If you want to use a picture of an impulse response as a means to estimate how audible ringing might be, then you should plot power (in dB) vs. time; e.g. see the graphs at the bottom of the page here: http://sox.sourceforge.net/SoX/Resampling


The chart at the top of that page illustrates the conceptual problem. It portrays signals that are 90 dB down and are also > 20 KHz as if they are easily perceptible by means of making them as visible as signals at FS.

??  The point is that you seem to be trying to determine whether an LPF's ringing could possibly be audible by looking at its impulse response.  This means being able to see when the ringing is perhaps 80dB down.  So in the case of your roughly 35-pixel-high linear-scale impulse response above, you need to be able to discern 0.0035 of a pixel:


Displaying the vertical scale for the impulse response as power in dB (logarithmic) would remove this problem (don't know about CEP, but in Audacity this is just a simple click on a drop-down menu).

Various pictures from Arny's posts

Reply #49
If you want to use a picture of an impulse response as a means to estimate how audible ringing might be, then you should plot power (in dB) vs. time; e.g. see the graphs at the bottom of the page here: http://sox.sourceforge.net/SoX/Resampling


The chart at the top of that page illustrates the conceptual problem. It portrays signals that are 90 dB down and are also > 20 KHz as if they are easily perceptible by means of making them as visible as signals at FS.

??  The point is that you seem to be trying to determine whether an LPF's ringing could possibly be audible by looking at its impulse response.  This means being able to see when the ringing is perhaps 80dB down.  So in the case of your roughly 35-pixel-high linear-scale impulse response above, you need to be able to discern 0.0035 of a pixel:


Displaying the vertical scale for the impulse response as power in dB (logarithmic) would remove this problem (don't know about CEP, but in Audacity this is just a simple click on a drop-down menu).


I'm not trying to determine whether an LPF's ringing could possibly be audible by looking at its impulse response by means of analysis of objective evaluations. I'm trying to do proper listening tests to understand the situation better.

I'm simply pointing out that an existing tool seems to have a bias towards making a graphical mountain over what might be a perceptual mole hill.

 
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