diff --git a/src/include/86box/snd_ad1848.h b/src/include/86box/snd_ad1848.h
index 34693c675..0656e4d02 100644
--- a/src/include/86box/snd_ad1848.h
+++ b/src/include/86box/snd_ad1848.h
@@ -97,7 +97,7 @@ extern void ad1848_update(ad1848_t *ad1848);
 extern void ad1848_speed_changed(ad1848_t *ad1848);
 extern void ad1848_set_cd_audio_channel(void *priv, int channel);
 extern void ad1848_filter_cd_audio(int channel, double *buffer, void *priv);
-extern void ad1848_filter_aux2(void* priv, double* out_l, double* out_r);
+extern void ad1848_filter_channel(void* priv, int channel, double* out_l, double* out_r);
 
 extern void ad1848_init(ad1848_t *ad1848, uint8_t type);
 
diff --git a/src/sound/snd_ad1848.c b/src/sound/snd_ad1848.c
index 13baca4ab..d721691d5 100644
--- a/src/sound/snd_ad1848.c
+++ b/src/sound/snd_ad1848.c
@@ -770,20 +770,24 @@ ad1848_filter_cd_audio(int channel, double *buffer, void *priv)
 }
 
 void
-ad1848_filter_aux2(void *priv, double *out_l, double *out_r)
+ad1848_filter_channel(void *priv, int channel, double *out_l, double *out_r)
 {
     const ad1848_t *ad1848 = (ad1848_t *) priv;
 
-    if (ad1848->regs[4] & 0x80) {
+    const int max_channel = (ad1848->type >= AD1848_TYPE_CS4231) ? 31 : 15;
+    if (channel > max_channel)
+        channel = max_channel;
+
+    if (ad1848->regs[channel] & 0x80) {
         *out_l = 0.0;
     } else {
-        *out_l = ((*out_l) * ad1848_vols_5bits_aux_gain[ad1848->regs[4] & 0x1f]) / 65536.0;
+        *out_l = ((*out_l) * ad1848_vols_5bits_aux_gain[ad1848->regs[channel] & 0x1f]) / 65536.0;
     }
 
-    if (ad1848->regs[5] & 0x80) {
+    if (ad1848->regs[channel + 1] & 0x80) {
         *out_r = 0.0;
     } else {
-        *out_r = ((*out_r) * ad1848_vols_5bits_aux_gain[ad1848->regs[5] & 0x1f]) / 65536.0;
+        *out_r = ((*out_r) * ad1848_vols_5bits_aux_gain[ad1848->regs[channel + 1] & 0x1f]) / 65536.0;
     }
 }
 
diff --git a/src/sound/snd_optimc.c b/src/sound/snd_optimc.c
index 7d1759cfe..274bbd568 100644
--- a/src/sound/snd_optimc.c
+++ b/src/sound/snd_optimc.c
@@ -85,7 +85,7 @@ optimc_filter_opl(void *priv, double *out_l, double *out_r)
     if (optimc->cur_wss_enabled) {
         *out_l /= optimc->sb->mixer_sbpro.fm_l;
         *out_r /= optimc->sb->mixer_sbpro.fm_r;
-        ad1848_filter_aux2((void *) &optimc->ad1848, out_l, out_r);
+        ad1848_filter_channel((void *) &optimc->ad1848, AD1848_AUX2, out_l, out_r);
     }
 }