I tried to play this song on my iBook G4:
http://www.gnu.org/music/free-software-song.au
(this happens with many other .au and .wav files as well)

% file free-software-song.au
free-software-song.au: Sun/NeXT audio data: 8-bit ISDN mu-law, mono, 8000 Hz
% audioplay free-software-song.au
audioplay: failed to open /dev/sound0: Invalid argument

I enabled debug messages in sys/dev/audio.c, added some more in
snapper.c, and found this in dmesg:

audio_open: flags=0x2 sc=0xd019c000 hdl=0xd015c800
audiosetinfo sc=0xd019c000 ai=0xd5dd7c20
snapper_set_rate: invalid rate 1048608
audiosetinfo: hw->set_params() failed with 22
audio_open: flags=0x2 sc=0xd019c000 hdl=0xd015c800
audiosetinfo sc=0xd019c000 ai=0xd5dd7c20
snapper_set_rate: invalid rate 1048608
audiosetinfo: hw->set_params() failed with 22

1048608 seems like an odd rate; snapper_set_rate accepts only 8000,
44100 and 48000.  Why does audiosetinfo try 1048608?  Does anyone else
see this problem?

Magnus