diff --git a/hw/wm8750.c b/hw/wm8750.c
index ce43c23..4c864e4 100644
--- a/hw/wm8750.c
+++ b/hw/wm8750.c
@@ -223,7 +223,7 @@ static void wm8750_set_format(WM8750State *s)
                     CODEC ".headphone", s, wm8750_audio_out_cb, &out_fmt);
     /* MONOMIX is also in stereo for simplicity */
     s->dac_voice[2] = AUD_open_out(&s->card, s->dac_voice[2],
-                    CODEC ".monomix", s, wm8750_audio_out_cb, &out_fmt);
+                    CODEC ".monomix", s, wm8750_audio_out_cb, &monoout_fmt);
     /* no sense emulating OUT3 which is a mix of other outputs */
 
     wm8750_vol_update(s);