diff --git a/src/conf/cards/Maestro3.conf b/src/conf/cards/Maestro3.conf
index 2916cf49..94323227 100644
--- a/src/conf/cards/Maestro3.conf
+++ b/src/conf/cards/Maestro3.conf
@@ -21,8 +21,10 @@ Maestro3.pcm.default {
 	playback.pcm {
 		type plug
 		slave.pcm {
+			# we need to specify device and subdevice numbers
+			# for a device with multiple substreams
 			@func concat
-			strings [ "dmix:" $CARD ]
+			strings [ "dmix:" $CARD ",0,0" ]
 		}
 	}
 	capture.pcm {