diff --git a/src/add-ons/media/media-add-ons/mixer/AudioMixer.cpp b/src/add-ons/media/media-add-ons/mixer/AudioMixer.cpp
index bcd22162e8..2987a8a65f 100644
--- a/src/add-ons/media/media-add-ons/mixer/AudioMixer.cpp
+++ b/src/add-ons/media/media-add-ons/mixer/AudioMixer.cpp
@@ -450,7 +450,7 @@ AudioMixer::FormatChangeRequested(const media_source &source, const media_destin
 	printf("AudioMixer: buffer duration is %Ld usecs\n", BufferDuration());
 
 	// Our internal latency is at least the length of a full output buffer
-	fInternalLatency = bigtime_t(1.2 * BufferDuration());
+	fInternalLatency = bigtime_t(1.6 * BufferDuration());
 	printf("AudioMixer: Internal latency is %Ld usecs\n", fInternalLatency);
 	
 	SetEventLatency(fDownstreamLatency + fInternalLatency);
@@ -634,7 +634,7 @@ AudioMixer::Connect(status_t error, const media_source &source, const media_dest
 	printf("AudioMixer: buffer duration is %Ld usecs\n", BufferDuration());
 
 	// Our internal latency is at least the length of a full output buffer
-	fInternalLatency = bigtime_t(1.2 * BufferDuration());
+	fInternalLatency = bigtime_t(1.6 * BufferDuration());
 	printf("AudioMixer: Internal latency is %Ld usecs\n", fInternalLatency);
 	
 	SetEventLatency(fDownstreamLatency + fInternalLatency);
@@ -778,7 +778,7 @@ AudioMixer::HandleEvent(const media_timed_event *event, bigtime_t lateness, bool
 			printf("AudioMixer::HandleEvent: B_START\n");
 			if (RunState() != B_STARTED) {
 				fCore->Lock();
-				fCore->Start(event->event_time);
+				fCore->Start();
 				fCore->Unlock();
 			}
 			break;
diff --git a/src/add-ons/media/media-add-ons/mixer/MixerCore.cpp b/src/add-ons/media/media-add-ons/mixer/MixerCore.cpp
index a052b43013..592d558193 100644
--- a/src/add-ons/media/media-add-ons/mixer/MixerCore.cpp
+++ b/src/add-ons/media/media-add-ons/mixer/MixerCore.cpp
@@ -36,6 +36,8 @@ MixerCore::MixerCore(AudioMixer *node)
 	fOutput(0),
 	fNextInputID(1),
 	fRunning(false),
+	fStarted(false),
+	fOutputEnabled(true),
 	fResampler(0),
 	fMixBuffer(0),
 	fMixBufferFrameRate(0),
@@ -93,6 +95,10 @@ MixerCore::AddOutput(const media_output &output)
 	fOutput = new MixerOutput(this, output);
 	// the output format might have been adjusted inside MixerOutput
 	ApplyOutputFormat();
+	
+	ASSERT(!fRunning);
+	if (fStarted && fOutputEnabled)
+		StartMixThread();
 }
 
 bool
@@ -116,8 +122,13 @@ MixerCore::RemoveOutput()
 	ASSERT_LOCKED();
 	if (!fOutput)
 		return false;
+
+	if (fStarted)
+		StopMixThread();
+
 	delete fOutput;
 	fOutput = 0;
+	fOutputEnabled = true;
 	return true;
 }
 
@@ -169,16 +180,16 @@ MixerCore::OutputFormatChanged(const media_multi_audio_format &format)
 {
 	ASSERT_LOCKED();
 	
-	bool wasrunning = fRunning;
+	bool was_started = fStarted;
 
-	if (wasrunning)
+	if (was_started)
 		Stop();
 
 	fOutput->ChangeFormat(format);
 	ApplyOutputFormat();
 
-	if (wasrunning)
-		Start(0);
+	if (was_started)
+		Start();
 }
 
 void
@@ -258,16 +269,55 @@ MixerCore::EnableOutput(bool enabled)
 {
 	ASSERT_LOCKED();
 	printf("MixerCore::EnableOutput %d\n", enabled);
+	fOutputEnabled = enabled;
+
+	if (fRunning && !fOutputEnabled)
+		StopMixThread();
+
+	if (!fRunning && fOutput && fStarted && fOutputEnabled)
+		StartMixThread();
 }
 
-void
-MixerCore::Start(bigtime_t time)
+bool
+MixerCore::Start()
 {
 	ASSERT_LOCKED();
 	printf("MixerCore::Start\n");
-	if (fRunning)
-		return;
+	if (fStarted)
+		return false;
 		
+	fStarted = true;
+	
+	ASSERT(!fRunning);
+	
+	// only start the mix thread if we have an output
+	if (fOutput && fOutputEnabled)
+		StartMixThread();
+
+	return true;
+}
+
+bool
+MixerCore::Stop()
+{
+	ASSERT_LOCKED();
+	printf("MixerCore::Stop\n");
+	if (!fStarted)
+		return false;
+		
+	if (fRunning)
+		StopMixThread();
+
+	fStarted = false;
+	return true;
+}
+
+void
+MixerCore::StartMixThread()
+{
+	ASSERT(fOutputEnabled == true);
+	ASSERT(fRunning == false);
+	ASSERT(fOutput);
 	fRunning = true;
 	fMixThreadWaitSem = create_sem(0, "mix thread wait");
 	fMixThread = spawn_thread(_mix_thread_, "Yeah baby, very shagadelic", 12, this);
@@ -275,13 +325,9 @@ MixerCore::Start(bigtime_t time)
 }
 
 void
-MixerCore::Stop()
+MixerCore::StopMixThread()
 {
-	ASSERT_LOCKED();
-	printf("MixerCore::Stop\n");
-	if (!fRunning)
-		return;
-
+	ASSERT(fRunning == true);
 	ASSERT(fMixThread > 0);
 	ASSERT(fMixThreadWaitSem > 0);
 	
@@ -294,12 +340,14 @@ MixerCore::Stop()
 	fRunning = false;
 }
 
+/*
 bool
 MixerCore::IsStarted()
 {
 	ASSERT_LOCKED();
 	return fRunning;
 }
+*/
 
 int32
 MixerCore::_mix_thread_(void *arg)
@@ -321,14 +369,19 @@ MixerCore::MixThread()
 	// The broken BeOS R5 multiaudio node starts with time 0,
 	// then publishes negative times for about 50ms, publishes 0
 	// again until it finally reaches time values > 0
+	Lock();
 	start = fTimeSource->Now();
+	Unlock();
 	while (start <= 0) {
 		printf("MixerCore: delaying MixThread start, timesource is at %Ld\n", start);
 		snooze(1000);
+		Lock();
 		start = fTimeSource->Now();
+		Unlock();
 	}
 
-	latency = bigtime_t(0.2 * buffer_duration(fOutput->MediaOutput().format.u.raw_audio));
+	Lock();
+	latency = bigtime_t(0.4 * buffer_duration(fOutput->MediaOutput().format.u.raw_audio));
 	
 	printf("MixerCore: starting MixThread at %Ld with latency %Ld and downstream latency %Ld\n", start, latency, fDownstreamLatency);
 
@@ -337,6 +390,7 @@ MixerCore::MixThread()
 	int64 temp = frames_for_duration(fMixBufferFrameRate, start	);
 	frame_base = ((temp / fMixBufferFrameCount) + 1) * fMixBufferFrameCount;
 	time_base = duration_for_frames(fMixBufferFrameRate, frame_base);
+	Unlock();
 	
 	printf("starting MixThread, start %Ld, time_base %Ld, frame_base %Ld\n", start, time_base, frame_base);
 	
@@ -344,7 +398,8 @@ MixerCore::MixThread()
 	frame_pos = 0;
 	for (;;) {
 		status_t rv;
-		rv = acquire_sem_etc(fMixThreadWaitSem, 1, B_ABSOLUTE_TIMEOUT, fTimeSource->RealTimeFor(event_time, latency + fDownstreamLatency));
+//		rv = acquire_sem_etc(fMixThreadWaitSem, 1, B_ABSOLUTE_TIMEOUT, fTimeSource->RealTimeFor(event_time, latency + fDownstreamLatency));
+		rv = acquire_sem_etc(fMixThreadWaitSem, 1, B_ABSOLUTE_TIMEOUT, fTimeSource->RealTimeFor(event_time, 0) - latency - fDownstreamLatency);
 		if (rv == B_INTERRUPTED)
 			continue;
 		if (rv != B_TIMED_OUT && rv < B_OK)
diff --git a/src/add-ons/media/media-add-ons/mixer/MixerCore.h b/src/add-ons/media/media-add-ons/mixer/MixerCore.h
index 5f38ff4de5..a142722124 100644
--- a/src/add-ons/media/media-add-ons/mixer/MixerCore.h
+++ b/src/add-ons/media/media-add-ons/mixer/MixerCore.h
@@ -37,10 +37,13 @@ public:
 	void SetOutputBufferGroup(BBufferGroup *group);
 	void SetTimingInfo(BTimeSource *ts, bigtime_t downstream_latency);
 	void EnableOutput(bool enabled);
-	void Start(bigtime_t time);
-	void Stop();
+	bool Start();
+	bool Stop();
+	
+	void StartMixThread();
+	void StopMixThread();
 
-	bool IsStarted();
+//	bool IsStarted();
 	
 	uint32 OutputChannelCount();
 
@@ -55,7 +58,9 @@ private:
 	BList		*fInputs;
 	MixerOutput	*fOutput;
 	int32		fNextInputID;
-	bool		fRunning;
+	bool		fRunning;		// true = the mix thread is running
+	bool		fStarted;		// true = mix thread should be started of it is not running
+	bool		fOutputEnabled; // true = mix thread should be started of it is not running
 
 	Resampler	**fResampler; // array
 
diff --git a/src/add-ons/media/media-add-ons/mixer/MixerInput.cpp b/src/add-ons/media/media-add-ons/mixer/MixerInput.cpp
index 6a50513852..142f5e5a60 100644
--- a/src/add-ons/media/media-add-ons/mixer/MixerInput.cpp
+++ b/src/add-ons/media/media-add-ons/mixer/MixerInput.cpp
@@ -61,9 +61,6 @@ MixerInput::MixerInput(MixerCore *core, const media_input &input, float mixFrame
 	// fMixerChannelInfo and fMixerChannelCount will be initialized by UpdateMixerChannels()
 
 	SetMixBufferFormat(mixFrameRate, mixFrameCount);
-	UpdateChannelDesignations();
-	UpdateMixerChannels();
-	
 	
 	// XXX a test:
 /*
@@ -95,7 +92,10 @@ MixerInput::BufferReceived(BBuffer *buffer)
 	size_t size;
 	bigtime_t start;
 	
-	ASSERT(fMixBuffer);
+	if (!fMixBuffer) {
+		printf("MixerInput::BufferReceived: dropped incoming buffer as we don't have a mix buffer\n");
+		return;
+	}
 	
 	data = buffer->Data();
 	size = buffer->SizeUsed();
@@ -305,8 +305,6 @@ MixerInput::UpdateMixerChannels()
 	mixer_chan_info *old_mixer_channel_info;
 	uint32 old_mixer_channel_count;
 
-	ASSERT(fMixBuffer);
-	
 	printf("UpdateMixerChannels: enter\n");
 	
 	for (int i = 0; i < fInputChannelCount; i++)
@@ -350,7 +348,7 @@ MixerInput::UpdateMixerChannels()
 		int j;
 		for (j = 0; j < fInputChannelCount; j++) {
 			if (fInputChannelInfo[j].designations & ChannelTypeToChannelMask(fMixerChannelInfo[i].type)) {
-				fMixerChannelInfo[i].buffer_base = &fMixBuffer[j];
+				fMixerChannelInfo[i].buffer_base = fMixBuffer ? &fMixBuffer[j] : 0;
 				break;
 			}
 		}
@@ -389,7 +387,7 @@ MixerInput::GetMixerChannelCount()
 void
 MixerInput::GetMixerChannelInfo(int channel, int64 framepos, const float **buffer, uint32 *sample_offset, int *type, float *gain)
 {
-	ASSERT(fMixBuffer);
+	ASSERT(fMixBuffer); // this function should not be called if we don't have a mix buffer!
 	ASSERT(channel >= 0 && channel < fMixerChannelCount);
 	int32 offset = framepos % fMixBufferFrameCount;
 	if (channel == 0) printf("GetMixerChannelInfo: frames %ld to %ld\n", offset, offset + debugMixBufferFrames);
@@ -420,10 +418,25 @@ MixerInput::GetMixerChannelGain(int channel)
 void
 MixerInput::SetMixBufferFormat(int32 framerate, int32 frames)
 {
+	printf("MixerInput::SetMixBufferFormat: framerate %ld, frames %ld\n", framerate, frames);
+
 	fMixBufferFrameRate = framerate;
 	debugMixBufferFrames = frames;
 
-	printf("MixerInput::SetMixBufferFormat: framerate %ld, frames %ld\n", framerate, frames);
+	// frames and/or framerate can be 0 (if no output is connected)
+	if (framerate == 0 || frames == 0) {
+		if (fMixBuffer) {
+			rtm_free(fMixBuffer);
+			fMixBuffer = 0;
+		}
+		for (int i = 0; i < fInputChannelCount; i++)
+			fInputChannelInfo[i].buffer_base = 0;
+		fMixBufferFrameCount = 0;
+
+		UpdateChannelDesignations();
+		UpdateMixerChannels();
+		return;
+	}
 
 	// make fMixBufferFrameCount an integral multiple of frames,
 	// but at least 3 times duration of our input buffer
@@ -451,4 +464,7 @@ MixerInput::SetMixBufferFormat(int32 framerate, int32 frames)
 
 	for (int i = 0; i < fInputChannelCount; i++)
 		fInputChannelInfo[i].buffer_base = &fMixBuffer[i];
+
+	UpdateChannelDesignations();
+	UpdateMixerChannels();
 }