diff --git a/audio/chmap.c b/audio/chmap.c
index fcdb95edb3..77bd998835 100644
--- a/audio/chmap.c
+++ b/audio/chmap.c
@@ -102,10 +102,12 @@ static const struct mp_chmap default_layouts[MP_NUM_CHANNELS + 1] = {
 
 // The channel order was lavc/waveex, but differs from lavc for 5, 6 and 8
 // channels. 3 and 7 channels were likely undefined (no ALSA support).
+// I'm not sure about the 4 channel case: ALSA uses "quad", while the ffmpeg
+// default layout is "4.0".
 static const char *mplayer_layouts[MP_NUM_CHANNELS + 1] = {
     [1] = "mono",
     [2] = "stereo",
-    [4] = "4.0",
+    [4] = "quad",
     [5] = "5.0(alsa)",
     [6] = "5.1(alsa)",
     [8] = "7.1(alsa)",
diff --git a/audio/out/ao_alsa.c b/audio/out/ao_alsa.c
index 93327881e5..d2e8180608 100644
--- a/audio/out/ao_alsa.c
+++ b/audio/out/ao_alsa.c
@@ -325,7 +325,7 @@ static const char *device_channel_layouts[][2] = {
     {"rear",            "bl-br"},
     {"center_lfe",      "fc-lfe"},
     {"side",            "sl-sr"},
-    {"surround40",      "fl-fr-fc-bc"},
+    {"surround40",      "fl-fr-bl-br"},
     {"surround50",      "fl-fr-bl-br-fc"},
     {"surround41",      "fl-fr-bl-br-lfe"},
     {"surround51",      "fl-fr-bl-br-fc-lfe"},