Yes it is, I tested it in xterm with play-sound command and it worked but not it claws-mail. I think I have it wrong in claws-mail because I have use it with path and with no path, like: play-sound /usr/share/sounds/ui-new_email.wav but nothing happend. I don't understand. Is there in path possible something wrong but again why play-sound command produce sound in xterm? I'm little bit confused, seems easy to add that command but still I can't get it working.