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Various pictures from Arny's posts

Reply #125
I just installed Windows 10 today and I'm trying to work out some bugs. Luckily FB2K ABX seems to still work.
I'm going to sleep now but here's the log. I'll add more commentary tomorrow.
Code: [Select]
foo_abx 2.0.1 report
foobar2000 v1.3.3
2015-08-06 02:18:08

File A: digital_black_1644_2496.flac
SHA1: 5f1bdf3767076523d2065835e67f43a6ce08d580
File B: digital_black_2496.flac
SHA1: e8f61474e2fc7628ad3d276d0fb0f3ad61d53d98

Output:
DS : Primary Sound Driver
Crossfading: NO

02:18:08 : Test started.
02:20:42 : 01/01
02:20:49 : 02/02
02:20:57 : 03/03
02:21:04 : 04/04
02:21:35 : 05/05
02:21:57 : 06/06
02:22:13 : 07/07
02:22:33 : 08/08
02:22:49 : 09/09
02:22:58 : 10/10
02:22:58 : Test finished.

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

 -- signature --
55a32e802b4cb013b10c6cff3bdd6353695015b0
Whereas with the original files with the test tones I could hear a difference at a reasonable playback volume which wasn't clipping the audible range's content [hard to say what's happening with the ultrasonics at that point, I don't hear them], not so with these new digital black files; I had to raise the gain 15dB more. It very likely is "clipping" level at this point, had there been actual content to clip, that is. However the noise I'm hearing now and keying on can't be deemed "clipping distortion" nor "IM distortion" since there is no actual signal.

Various pictures from Arny's posts

Reply #126
[attachment=8370:2496_dig..._ds_1644.png]

I find it hard to believe I'm picking up on content that's 130 dB down [and  at my age I conk out at 13k, maybe 14k tops]. How about a pic from your dual trace oscope of A's actual noise floor vs B's actual noise floor?

Various pictures from Arny's posts

Reply #127
Update: I think with a quiet room I could even do the new digital black files at "0dB" volume setting on my preamp. I've had to overlook a faint hum problem (I would assume a ground loop) which I now realize I can kill by running my laptop on battery power instead of the AC cord. I'll see tomorrow if I can get the room quiet enough.

Various pictures from Arny's posts

Reply #128
Update: I think with a quiet room I could even do the new digital black files at "0dB" volume setting on my preamp. I've had to overlook a faint hum problem (I would assume a ground loop) which I now realize I can kill by running my laptop on battery power instead of the AC cord. I'll see tomorrow if I can get the room quiet enough.


It is not news that in many systems the system gain can be artificially elevated to the point where normally inaudible noise can be reliably heard.

So, one key element of a reasonable test is using reasonable gain settings.  Tests involving very low level signals such as these are especially error prone due to this influence.

Various pictures from Arny's posts

Reply #129
I'm new to RMAA and can't figure out how to take snapshots from the analyzer part, but here's a screen grab with another program.
I see now your image wasn't theoretical but rather was an actual measurement. Oops. I'm still having problems believing this sort of thing would be audible to me at a playback level that although "loud" doesn't clip normal content, "0db" on my Audyssey calibrated prepro, but I guess I can.

I also can't remember how to bring my attachments I've successfully uploaded in another thread over to this one, but my RMAA analyzer screen grab shot [my very first one! Woo hoo] shows the same thing as your image. 
Here's a link instead.

Various pictures from Arny's posts

Reply #130
I didn't even download the samples but i see the pic. You still use some weird CEP settings for resampling?
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Various pictures from Arny's posts

Reply #131
I didn't even download the samples but i see the pic. You still use some weird CEP settings for resampling?


No weirdness, just careful tuning based on best knowledge I have about audibility.  Q=150

You could lower yourself to try to ABX them for about 5 minutes... ;-)



Various pictures from Arny's posts

Reply #132
Measurements related to AP24192 and Beach Audio Asynch USB

Beach Audio Xmos Asynch USB AK4490 DAC eBay

AP 24192 loop back

[attachment=8377:ap_24192_1_KHz.png]

AP24192 input terminated by 50 ohm

[attachment=8374:ap_24192__50_Zs_.png]

Beach Audio DAC 1 KHz with  TRS->RCA adapters and RCA cables  DAC Vout = 1.29 volts

[attachment=8375:ap_24192..._rca-trs.png]

Beach Audio DAC 1 KHz with Special TRS->RCA cables

[attachment=8376:ap_24192..._rca-trs.png]

Special RCA -> TRS cable

[attachment=8378:special_TRS_RCA.png]

Various pictures from Arny's posts

Reply #133
44 KHz SR frequency response  of Beach Audio Xmos Asynch USB AK4490 DAC (eBay):

[attachment=8379:ap_24192...dio_4424.png]

Notice roll off commencing @ 10 KHz and 5 dB down at 20 KHz.

Very similar to Pono player:


Various pictures from Arny's posts

Reply #134
Jitter test files - various degrees of audibility

No jitter (reference)

[attachment=8386:no__jitter.flac]

High, audible jitter

[attachment=8387:30_Hz_ma...tter_0.1.flac]

Harder to hear jitter

[attachment=8385:30_Hz_ji...vel_.025.flac]


Various pictures from Arny's posts

Reply #136
Hardware ABX Comparator Schematics

[attachment=8412:ABX0001s.jpg]

[attachment=8413:ABX0002s.jpg]

[attachment=8414:ABX0003s.jpg]

[attachment=8415:ABX0004s.jpg]


Re: Various pictures from Arny's posts

Reply #138
Audio check 8 versus 16  bit resolution files as individual, downloadable flac files along with evidence of  a reason why you should hear a difference even if you can't tell the difference between 8 and 16 bits (in context)



Re: Various pictures from Arny's posts

Reply #141
Bucket aligned multitones @ 2496 for technical tests

The test frequencies align with the bucket frequencies in a 96 kHz 65k point FFT so they tend to present more uniformly. In CEP these are about +/- 0.1 dB or better.

I threw in a swish for grins and giggles. This is a complex tone that will tend to present as a flat 65k FFT with a minimal amount of data.

 
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