... German Speech sample - average bit rate 31 kbps - and the codec was still performing best on average - even compared to much higher bit rate contenders ...
Interesting that you mentioned this sample. Surprisingly I found all contenders to be unusable for encoding it even though it is "only" a speech sample. The strong echo effect made the speech unpleasant and very different from the original - like the person speaking was moved to a cave. I actually found the low anchor better than the contenders with this sample.
My results:
ABC/HR for Java, Version 0.52b, 08 joulukuu 2006
Testname: Sample16: spmg54_1
Tester: Alex B
1R = Sample16\Sample16_1.wav
2L = Sample16\Sample16_5.wav
3L = Sample16\Sample16_4.wav
4L = Sample16\Sample16_6.wav
5L = Sample16\Sample16_3.wav
6R = Sample16\Sample16_2.wav
Ratings on a scale from 1.0 to 5.0
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General Comments:
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1R File: Sample16\Sample16_1.wav
1R Rating: 1.0
1R Comment: strong echo
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2L File: Sample16\Sample16_5.wav
2L Rating: 4.5
2L Comment:
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3L File: Sample16\Sample16_4.wav
3L Rating: 1.4
3L Comment: some echo
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4L File: Sample16\Sample16_6.wav
4L Rating: 1.8
4L Comment: low anchor - most lowpassed, but more pleasant than the echo effect that the other contenders produce
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5L File: Sample16\Sample16_3.wav
5L Rating: 1.3
5L Comment: distorded, some echo
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6R File: Sample16\Sample16_2.wav
6R Rating: 1.3
6R Comment: echo
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ABX Results:
Original vs Sample16\Sample16_5.wav
8 out of 8, pval = 0.0030
---- Detailed ABX results ----
Original vs Sample16\Sample16_5.wav
Playback Range: 06.662 to 09.154
2:15:23 AM p 1/1 pval = 0.5
2:15:47 AM p 2/2 pval = 0.25
2:15:57 AM p 3/3 pval = 0.125
2:16:02 AM p 4/4 pval = 0.062
2:16:06 AM p 5/5 pval = 0.031
2:16:10 AM p 6/6 pval = 0.015
2:16:16 AM p 7/7 pval = 0.0070
2:16:30 AM p 8/8 pval = 0.0030