This is in response to a thread regarding a perceived improvement in sound quality after applying mp3gain.
http://www.hydrogenaudio.org/forums/index....showtopic=57525

Included are two 30 second mp3 clips of the same source file. The data in one has been amplified by 6dB with mp3gain and has been given a replaygain value of 0dB. The other mp3 was given a replaygain value of 6dB but has otherwise been left alone.

When attempting to ABX these tracks, make sure to tell foobar2000 to apply replaygain but without any additional preamplification.