@muto: hmm, apparently libao supports few user configurable options:
ao_alsa_options[] = { "dev", "id", "buffer_time", "period_time", "use_mmap", "matrix", "verbose",
"quiet", "debug" };
ao_pulse_options[] = { "server", "sink", "dev", "id", "verbose", "quiet", "matrix", "debug",
"client_name" "buffer_time" };
ao_esd_options[] = { "server", "host", "matrix", "verbose", "quiet", "debug", "client_name" };

wild guess, edit /home/user/.libao and adding there:
default_driver=alsa
dev=hw:1,0
(though i think i force pulse in libao (for reasons) so you might try: )
default_driver=pulse
dev=dont-really-know-what-to-put-there-maybe hw:1,0 too?