If you mean Ethan's test, I had no trouble telling the difference:
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foo_abx 1.3.4 report
foobar2000 v1.3.2
2014/07/18 06:40:07
File A: C:\Users\Amir\Music\Ethan Soundblaster\sb20x_original.wav
File B: C:\Users\Amir\Music\Ethan Soundblaster\sb20x_pass1.wav
06:40:07 : Test started.
06:41:03 : 01/01 50.0%
06:41:16 : 02/02 25.0%
06:41:24 : 03/03 12.5%
06:41:33 : 04/04 6.3%
06:41:53 : 05/05 3.1%
06:42:02 : 06/06 1.6%
06:42:22 : 07/07 0.8%
06:42:34 : 08/08 0.4%
06:42:43 : 09/09 0.2%
06:42:56 : 10/10 0.1%
06:43:08 : 11/11 0.0%
06:43:16 : Test finished.
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Total: 11/11 (0.0%)
So 100% detection for even one pass.
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Granted, many people could not but the difference can be there.
I’m not sure its that one many people done this over the years , sorry to not have any source