Aleksander Korzynski pointed out to me the recent LAME heresy with respect to Replay Gain: rather than using the 83 dB SPL reference specified by the Replay Gain proposed standard, LAME uses a reference of 89 dB as of version 3.95.1.

Combined with the default pre-amp gain of +6 dB implemented in madplay, this often results in an over-amplified signal and clipping when Replay Gain is enabled.

I've just released version 0.15.2b of madplay that compensates for this problem:

ftp://ftp.mars.org/pub/mpeg/madplay-0.15.2b.tar.gz

Cheers,