Succesful ABX of 24/96 vs. 16/44.1 Options

[googlebot]

The maximum sample rate of my digital output is 96 kHz at 24 bit. To eliminate as many variables as possible I locked the output to that format and pre-converted the test files accordingly using the highest quality options available. As source material I have used the 24bit/192kHz track from this thread.

The high resolution contestant (24/96) was produced using the following settings:

CODE

sox Sample_192000Hz_24bit.wav 24-96000.wav rate -v 96000 dither -s

That is the setting recommended by Sox' developers for SRC with large target rates. Basically linear phase filters and sloped TPDF dither.

For the Redbook contestant, the 24bit/192khz track was first down-sampled to 16bit/441000Hz:

CODE

sox Sample_192000Hz_24bit.wav -b 16 16-44100.wav rate -v 44100 dither -s

And then up-sampled to 24bit/96kHz, again at the highest quality settings:

CODE

sox 16-44100.wav -b 24 16-44100-24-96000.wav rate -v 96000 dither -s

My hearing tops at about 17 kHz. Still I can hear pretty clear difference over a pair of Elac FS 607 X-Jet speakers, which are rated for 28-50000Hz (IEC 268-5):

CODE

foo_abx 1.3.4 report
foobar2000 v1.0.3
2010/06/07 18:25:51

File A: C:\Dokumente und Einstellungen\Christian\Desktop\16-441to24-96.wav
File B: C:\Dokumente und Einstellungen\Christian\Desktop\24-96.wav

18:25:51 : Test started.
18:26:44 : 01/01  50.0%
18:27:09 : 02/02  25.0%
18:27:26 : 03/03  12.5%
18:27:44 : 04/04  6.3%
18:28:00 : 05/05  3.1%
18:28:21 : 06/06  1.6%
18:28:38 : 07/07  0.8%
18:28:52 : 08/08  0.4%
18:29:06 : 09/09  0.2%
18:29:17 : 10/10  0.1%
18:29:33 : 11/11  0.0%
18:29:46 : 12/12  0.0%
18:30:03 : 13/13  0.0%
18:30:26 : 14/14  0.0%
18:30:42 : 15/15  0.0%
18:31:04 : 16/16  0.0%
18:31:08 : Test finished.

----------
Total: 16/16 (0.0%)

I do not think, that I actually hear the presence or absence of stationary HF content. But what I am hearing is louder and somewhat smeared sounding transients in the Redbook version. That is exactly the type of pass-band artifact to be expected from low-pass filtering, but until lately I hadn't considered that to be audible, when done right. And since that step is necessary it can also not be avoided for Redbook delivery.

I do not hear a difference over my regular Canton speakers, which top at about 20kHz! Neither over my Grado headphones. Since both act as a mechanical low pass, I think they just cause the same artifacts in the pass band as the digital low-passing.

Until today I have mostly laughed at high resolution apologists. But that ABX result somewhat changed my perspective. Maybe those, who say that you do need excellent speakers to hear a difference are actually right? On the other hand this is just one very artificial and synthetic sample. The results can very likely not be extrapolated to real world recordings. I don't know. What do you all think?

The speakers are here for testing right now, but I think I'm going to buy them.

PS: I have uploaded the samples.

This post has been edited by googlebot: Jun 7 2010, 18:36

[Brand]

I did a quick test and couldn't ABX them.
But for those who can easily hear it, I'd like to propose testing 24/44.1 instead of 16/44.1, just to see if the difference is due to SRC or to bit reduction/dithering.

And eventually 16/96 vs 16/44.1.

And perhaps with a different resampler.