diff --git a/src/mame/drivers/drgnmst.cpp b/src/mame/drivers/drgnmst.cpp
index 3cd5af8c544..da0bfcfca3d 100644
--- a/src/mame/drivers/drgnmst.cpp
+++ b/src/mame/drivers/drgnmst.cpp
@@ -401,16 +401,13 @@ MACHINE_CONFIG_START(drgnmst_state::drgnmst)
 	MCFG_PALETTE_ADD("palette", 0x2000)
 
 	/* sound hardware */
-	SPEAKER(config, "lspeaker").front_left();
-	SPEAKER(config, "rspeaker").front_right();
+	SPEAKER(config, "mono").front_center();
 
 	MCFG_DEVICE_ADD("oki1", OKIM6295, 32000000/32, okim6295_device::PIN7_HIGH)
-	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "lspeaker", 0.50)
-	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "rspeaker", 0.50)
+	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.00)
 
 	MCFG_DEVICE_ADD("oki2", OKIM6295, 32000000/32, okim6295_device::PIN7_HIGH)
-	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "lspeaker", 0.50)
-	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "rspeaker", 0.50)
+	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.00)
 MACHINE_CONFIG_END