Hello,

Performing some ABX today, I found a sample not too hard to ABX. I was surprised by the fact that the problem was the stereo, but doing some search in the forum, I found that Vorbis is known to alter stereo at low bitrates.

Here is the sample : http://3141592.pio2001.online.fr/files/har.../Blinddance.zip

ABX 8/8 up to -q4. The high frequency electronic sound collapses into mono.

The bitreates are :
Q2 : 98 kbps
Q3 : 109 kbps
Q4 : 122 kbps
Q5 : 164 kbps
Q6 : 186 kbps