Finalement réglé en faisant:
<$ timidity -iA -B2.8 -Os -EFreverb=0
Requested buffer size 16384, fragment size 8192
ALSA pcm 'default' set buffer size 16384, period size 5460 bytes
TiMidity starting in ALSA server mode
Opening sequencer port: 128:0 128:1 128:2 128:3>
Merci
EDIT MODO: ajout balises code manquantes