diff --git a/src/devices/bus/coleco/expansion/expansion.cpp b/src/devices/bus/coleco/expansion/expansion.cpp
index 87223699c2b..30b9c831dfb 100644
--- a/src/devices/bus/coleco/expansion/expansion.cpp
+++ b/src/devices/bus/coleco/expansion/expansion.cpp
@@ -26,6 +26,7 @@ DEFINE_DEVICE_TYPE(COLECO_EXPANSION, coleco_expansion_device, "coleco_expansion"
 coleco_expansion_device::coleco_expansion_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
 	device_t(mconfig, COLECO_EXPANSION, tag, owner, clock),
 	device_single_card_slot_interface<device_coleco_expansion_interface>(mconfig, *this),
+	device_mixer_interface(mconfig, *this),
 	m_program(*this, finder_base::DUMMY_TAG, -1),
 	m_io(*this, finder_base::DUMMY_TAG, -1),
 	m_int_handler(*this),
diff --git a/src/devices/bus/coleco/expansion/expansion.h b/src/devices/bus/coleco/expansion/expansion.h
index 421a2ab70d7..74dadfe57f3 100644
--- a/src/devices/bus/coleco/expansion/expansion.h
+++ b/src/devices/bus/coleco/expansion/expansion.h
@@ -55,7 +55,10 @@ class device_coleco_expansion_interface;
 //  BUS DEVICE
 //**************************************************************************
 
-class coleco_expansion_device : public device_t, public device_single_card_slot_interface<device_coleco_expansion_interface>
+class coleco_expansion_device :
+	public device_t,
+	public device_single_card_slot_interface<device_coleco_expansion_interface>,
+	public device_mixer_interface
 {
 public:
 	// construction/destruction
diff --git a/src/devices/bus/coleco/expansion/sgm.cpp b/src/devices/bus/coleco/expansion/sgm.cpp
index 8849813a241..d52d91f5b47 100644
--- a/src/devices/bus/coleco/expansion/sgm.cpp
+++ b/src/devices/bus/coleco/expansion/sgm.cpp
@@ -9,7 +9,6 @@
 #include "emu.h"
 #include "sgm.h"
 #include "sound/ay8910.h"
-#include "speaker.h"
 
 
 //**************************************************************************
@@ -47,10 +46,8 @@ void coleco_sgm_device::io_map(address_map &map)
 
 void coleco_sgm_device::device_add_mconfig(machine_config &config)
 {
-	SPEAKER(config, "mono").front_center();
-
 	ay8910_device &ay(AY8910(config, "ay", 7.15909_MHz_XTAL / 4));
-	ay.add_route(ALL_OUTPUTS, "mono", 1.00);
+	ay.add_route(ALL_OUTPUTS, DEVICE_SELF_OWNER, 1.0);
 }
 
 
diff --git a/src/mame/coleco/coleco.cpp b/src/mame/coleco/coleco.cpp
index 8580899cf89..46d749bbddf 100644
--- a/src/mame/coleco/coleco.cpp
+++ b/src/mame/coleco/coleco.cpp
@@ -603,6 +603,7 @@ void coleco_state::coleco(machine_config &config)
 	exp.set_io_space(m_maincpu, AS_IO);
 	exp.int_handler().set_inputline(m_maincpu, INPUT_LINE_IRQ0); // TODO: Merge with other IRQs?
 	exp.nmi_handler().set_inputline(m_maincpu, INPUT_LINE_NMI);
+	exp.add_route(ALL_OUTPUTS, "mono", 1.00);
 }
 
 void coleco_state::colecop(machine_config &config)