diff --git a/cmd/treatment/main.go b/cmd/treatment/main.go
index 8a6e30b9..31287927 100644
--- a/cmd/treatment/main.go
+++ b/cmd/treatment/main.go
@@ -35,7 +35,6 @@ import (
 	"io"
 	"os/exec"
 	"strconv"
-	"sync"
 	"time"
 
 	"bitbucket.org/ausocean/av/container/mts"
@@ -78,17 +77,18 @@ const (
 	i2cPort          = 1
 )
 
-// Treatment modes.
+// Channel modes.
 const (
-	modePaused    = "Paused"
-	modeTreatment = "Play"
-	modeCheck     = "Check"
+	modeStereo = "Stereo"
+	modeLeft = "LeftMono"
+	modeRight = "RightMono"
+	modeMute = "Mute"
 )
 
 // Variable map to send to netreceiver/vidgrind.
 var varMap = map[string]string{
-	"mode":          "enum:Paused,Play,Check",
-	"AudioFilePath": "string",
+	"speakerMode":    "enum:Stereo,LeftMono,RightMono,Mute",
+	"AudioFilePath":  "string",
 }
 
 func main() {
@@ -131,6 +131,10 @@ func main() {
 		log.Fatal("could not initialise revid", "error", err)
 	}
 
+	// Play the audio (audio will play even whilst muted).
+	log.Debug("Playing the audio")
+	go playAudio(filePtr, log)
+
 	// Start the control loop.
 	log.Debug("starting control loop")
 	run(rv, ns, filePtr, log, netLog)
@@ -140,10 +144,7 @@ func main() {
 // if var changes, changes current mode (paused,audio playback or soundcheck)
 func run(rv *revid.Revid, ns *netsender.Sender, file *string, l logging.Logger, nl *netlogger.Logger) {
 	var (
-		wg        sync.WaitGroup
-		audioQuit chan struct{}
-		treating  bool
-		vs        int
+		vs	int
 	)
 
 	for {
@@ -207,50 +208,76 @@ func run(rv *revid.Revid, ns *netsender.Sender, file *string, l logging.Logger,
 		}
 
 		l.Debug("checking mode")
-		switch ns.Mode() {
-		case modePaused:
-			stopAudio(&wg, &treating, audioQuit)
-			l.Info("mode is Paused, stopping revid")
-			rv.Stop()
-		case modeTreatment:
-			l.Debug("checking audio file path")
-			f := vars["AudioFilePath"]
-			if f != "" && *file != f {
-				file = &f
-				l.Info("updated audio file path, stopping audio", "AudioFilePath", f)
-				stopAudio(&wg, &treating, audioQuit)
-			}
-			if !treating {
-				l.Info("starting audio treatment")
-				rv.Stop()
-				audioQuit = make(chan struct{})
-				treating = true
-				wg.Add(1)
-				go playAudio(file, audioQuit, &wg, l)
-			}
-		case modeCheck:
-			stopAudio(&wg, &treating, audioQuit)
-			l.Info("sound checking")
-			err = rv.Start()
-			if err != nil {
-				l.Error("could not start revid", "error", err)
-				ns.SetMode(modePaused, &vs)
-				sleep(ns, l)
-				continue
-			}
-		default:
-			l.Warning("mode is not valid", "mode", ns.Mode())
-
-		}
-		l.Info("revid updated with new mode")
+		setChannels(vars["speakerMode"], l)
+		// l.Info("revid updated with new mode")
 		sleep(ns, l)
 	}
 }
 
-// playAudio is intended to be run as a routine. It will repeatedly play an audio file until
-// a signal is received to return. The entire audio file is played before the termination
-// signal chan is checked.
-func playAudio(file *string, quit chan struct{}, wg *sync.WaitGroup, l logging.Logger) {
+// setChannels handles the muting of one, both, or neither of the channels. It takes in speakerMode
+// and sets the relevant volumes.
+func setChannels(mode string, l logging.Logger) {
+	vols := ""
+	
+	l.Info("mode is", "mode", mode)
+
+	// Set the volume of each channel.
+	switch mode {
+	case modeStereo:
+		vols = "100%,100%"
+	case modeLeft:
+		vols = "0%,100%"
+	case modeRight:
+		vols = "100%,0%"
+	case modeMute:
+		vols = "0%,0%"
+	default:
+		// If an invalid option has been chosen, keep the previous setting.
+		return
+	}
+
+	// Create the command to change the channel volumes.
+	cmd := exec.Command("amixer", "sset", "Speaker", vols)
+	
+	// Pipe the output to stdout and stderr.
+	outPipe, err := cmd.StdoutPipe()
+	if err != nil {
+		l.Error("failed to pipe stdout", "error", err)
+	}
+	errPipe, err := cmd.StderrPipe()
+	if err != nil {
+		l.Error("failed to pipe stderr", "error", err)
+	}
+
+	// Execute the channel setting command.
+	err = cmd.Start()
+	if err != nil {
+		l.Error("channel setting failed", "error", err)
+	}
+
+	// Copy any std out to a buffer for logging.
+	var outBuff bytes.Buffer
+	go func() {
+		_, err = io.Copy(&outBuff, outPipe)
+		if err != nil {
+			l.Error("failed to copy out pipe", "error", err)
+		}
+	}()
+
+	// Copy any std error to a buffer for logging.
+	var errBuff bytes.Buffer
+	go func() {
+		_, err = io.Copy(&errBuff, errPipe)
+		if err != nil {
+			l.Error("failed to copy error pipe", "error", err)
+		}
+	}()
+
+	l.Info("mode set to", "mode", mode)
+}
+
+// playAudio is intended to be run as a routine. It will continuously run even whilst muted.
+func playAudio(file *string, l logging.Logger) {
 	var numPlays int
 	for {
 		cmd := exec.Command(audioCmd, *file)
@@ -303,30 +330,9 @@ func playAudio(file *string, quit chan struct{}, wg *sync.WaitGroup, l logging.L
 		if errBuff.Len() != 0 {
 			l.Error("errors from stderr", "stderr", string(errBuff.Bytes()))
 		}
-
-		// Check for audio signal halt.
-		// TODO: work out better way to do this. Doing it this way means we have to wait for
-		// the audio file to finish playing.
-		select {
-		case <-quit:
-			wg.Done()
-			return
-		default:
-		}
 	}
 }
 
-// stopAudio signals to the playAudio routine to terminate and then waits for it to
-// do so.
-func stopAudio(wg *sync.WaitGroup, treating *bool, signal chan struct{}) {
-	if !*treating {
-		return
-	}
-	close(signal)
-	wg.Wait()
-	*treating = false
-}
-
 // sleep uses a delay to halt the program based on the monitoring period
 // netsender parameter (mp) defined in the netsender.conf config.
 func sleep(ns *netsender.Sender, l logging.Logger) {