diff --git a/gtk2_ardour/midi_channel_selector.cc b/gtk2_ardour/midi_channel_selector.cc
index 4415a65f65..1b5baff7d5 100644
--- a/gtk2_ardour/midi_channel_selector.cc
+++ b/gtk2_ardour/midi_channel_selector.cc
@@ -160,7 +160,7 @@ MidiMultipleChannelSelector::~MidiMultipleChannelSelector()
 }
 
 void
-MidiMultipleChannelSelector::set_channel_mode(ChannelMode mode, uint8_t mask)
+MidiMultipleChannelSelector::set_channel_mode(ChannelMode mode, uint16_t mask)
 {
 	switch (mode) {
 	case AllChannels:
diff --git a/gtk2_ardour/midi_channel_selector.h b/gtk2_ardour/midi_channel_selector.h
index e026c12325..a72bea0cf1 100644
--- a/gtk2_ardour/midi_channel_selector.h
+++ b/gtk2_ardour/midi_channel_selector.h
@@ -72,7 +72,7 @@ public:
 	
 	virtual ~MidiMultipleChannelSelector();
 	
-	void set_channel_mode(ARDOUR::ChannelMode mode, uint8_t mask);
+	void set_channel_mode(ARDOUR::ChannelMode mode, uint16_t mask);
 
 	/**
 	 * @return each bit in the returned word represents a midi channel, eg. 
diff --git a/libs/ardour/ardour/midi_ring_buffer.h b/libs/ardour/ardour/midi_ring_buffer.h
index ec489ee5b6..7ffdcf3b8c 100644
--- a/libs/ardour/ardour/midi_ring_buffer.h
+++ b/libs/ardour/ardour/midi_ring_buffer.h
@@ -59,7 +59,7 @@ public:
 	 *     be forced to while reading.
 	 */
 	void set_channel_mode(ChannelMode mode, uint16_t mask) {
-		g_atomic_int_set(&_channel_mask, ((uint16_t)mode << 16) | mask);
+		g_atomic_int_set(&_channel_mask, (uint32_t(mode) << 16) | uint32_t(mask));
 	}
 
 	ChannelMode get_channel_mode() const {
@@ -67,7 +67,7 @@ public:
 	}
 	
 	uint16_t get_channel_mask() const {
-		return static_cast<ChannelMode>((g_atomic_int_get(&_channel_mask) & 0x0000FFFF));
+		return g_atomic_int_get(&_channel_mask) & 0x0000FFFF;
 	}
 	
 protected: