diff --git a/devices/awacs.h b/devices/awacs.h
index e7b5822..83d3205 100644
--- a/devices/awacs.h
+++ b/devices/awacs.h
@@ -144,8 +144,8 @@ private:
     int auto_inc;
 };
 
-
-class AwacsScreamer : public AwacsBase, public DMACallback {
+/** AWACs Screamer sound codec. */
+class AwacsScreamer : public AwacsBase {
 public:
     AwacsScreamer();
     ~AwacsScreamer();
@@ -153,7 +153,6 @@ public:
     uint32_t    snd_ctrl_read(uint32_t offset, int size);
     void        snd_ctrl_write(uint32_t offset, uint32_t value, int size);
 
-    /* DMACallback methods */
     void dma_start();
     void dma_end();
 
diff --git a/devices/dbdma.cpp b/devices/dbdma.cpp
index 184eb21..f813b25 100644
--- a/devices/dbdma.cpp
+++ b/devices/dbdma.cpp
@@ -29,6 +29,12 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <cstring>
 #include <loguru.hpp>
 
+void DMAChannel::set_callbacks(DbdmaCallback start_cb, DbdmaCallback stop_cb)
+{
+    this->start_cb = start_cb;
+    this->stop_cb  = stop_cb;
+}
+
 void DMAChannel::get_next_cmd(uint32_t cmd_addr, DMACmd* p_cmd) {
     /* load DMACmd from physical memory */
     memcpy((uint8_t*)p_cmd, mmu_get_dma_mem(cmd_addr, 16), 16);
@@ -241,7 +247,7 @@ void DMAChannel::start()
 
     this->queue_len = 0;
 
-    this->dma_cb->dma_start();
+    this->start_cb();
 }
 
 void DMAChannel::resume() {
@@ -259,5 +265,5 @@ void DMAChannel::abort() {
 
 void DMAChannel::pause() {
     LOG_F(INFO, "Pausing DMA channel");
-    this->dma_cb->dma_end();
+    this->stop_cb();
 }
diff --git a/devices/dbdma.h b/devices/dbdma.h
index 53e9a30..2b2d743 100644
--- a/devices/dbdma.h
+++ b/devices/dbdma.h
@@ -31,6 +31,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #include "dmacore.h"
 #include <cinttypes>
+#include <functional>
 
 /** DBDMA Channel registers offsets */
 enum DMAReg : uint32_t {
@@ -60,21 +61,14 @@ typedef struct DMACmd {
     uint16_t xfer_stat;
 } DMACmd;
 
-class DMACallback {
-public:
-    virtual void dma_start(void) = 0;
-    virtual void dma_end(void)   = 0;
-    //virtual void dma_push(uint8_t *buf, int size) = 0;
-    //virtual void dma_pull(uint8_t *buf, int size)  = 0;
-};
+typedef std::function<void(void)> DbdmaCallback;
 
 class DMAChannel : public DmaOutChannel {
 public:
-    DMAChannel(DMACallback* cb) {
-        this->dma_cb = cb;
-    };
+    DMAChannel()  = default;
     ~DMAChannel() = default;
 
+    void set_callbacks(DbdmaCallback start_cb, DbdmaCallback stop_cb);
     uint32_t reg_read(uint32_t offset, int size);
     void reg_write(uint32_t offset, uint32_t value, int size);
 
@@ -91,7 +85,9 @@ protected:
     void pause(void);
 
 private:
-    DMACallback* dma_cb = 0;
+    std::function<void(void)> start_cb; // DMA channel start callback
+    std::function<void(void)> stop_cb;  // DMA channel stop callback
+
     uint16_t ch_stat    = 0;
     uint32_t cmd_ptr    = 0;
 
diff --git a/devices/heathrow.cpp b/devices/heathrow.cpp
index 0958395..f8fc229 100644
--- a/devices/heathrow.cpp
+++ b/devices/heathrow.cpp
@@ -1,6 +1,6 @@
 /*
 DingusPPC - The Experimental PowerPC Macintosh emulator
-Copyright (C) 2018-20 divingkatae and maximum
+Copyright (C) 2018-21 divingkatae and maximum
                       (theweirdo)     spatium
 
 (Contact divingkatae#1017 or powermax#2286 on Discord for more info)
@@ -25,13 +25,14 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include "macio.h"
 #include "viacuda.h"
 #include <cinttypes>
+#include <functional>
 #include <iostream>
 #include <loguru.hpp>
 #include <cpu/ppc/ppcemu.h>
 
 /** Heathrow Mac I/O device emulation.
 
-    Author: Max Poliakovski 2019
+    Author: Max Poliakovski
 */
 
 using namespace std;
@@ -42,9 +43,14 @@ HeathrowIC::HeathrowIC() : PCIDevice("mac-io/heathrow") {
     this->viacuda = new ViaCuda();
     gMachineObj->add_subdevice("ViaCuda", this->viacuda);
 
+    // initialize sound chip and its DMA output channel, then wire them together
     this->screamer    = new AwacsScreamer();
-    this->snd_out_dma = new DMAChannel(this->screamer);
+    this->snd_out_dma = new DMAChannel();
     this->screamer->set_dma_out(this->snd_out_dma);
+    this->snd_out_dma->set_callbacks(
+        std::bind(&AwacsScreamer::dma_start, this->screamer),
+        std::bind(&AwacsScreamer::dma_end, this->screamer)
+    );
 
     this->mesh = new MESHController(HeathrowMESHID);
 }