Volume change when seeking in mp3

Hi,

I'm having some weird effect when setting softvol=true in
.mplayer/config. When I seek in large mp3 files with either the
right-arrow or up-arrow key, the volume sometimes jumps to 90%. It does
not happen without softvol=true. When I also set softvol-max=1000, it
jumps to 10% only. The volume jumps seem to correlate with this message:
AO: [oss] 24000Hz 2ch s16le (2 bytes per sample)

It seems to happen with any mp3 file, it doesn't happen with videos. I
don't know where that value is coming from, my .mplayer/config says
volume=20.

I don't know if this is an mplayer issue or if it's in ffmpeg. I'm using
libavformat version 58.76.100.

Gerhard