diff --git a/OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m b/OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m
index 1e0e6fd89..538133bcf 100644
--- a/OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m	
+++ b/OSBindings/Mac/Clock Signal/Audio/CSAudioQueue.m	
@@ -30,6 +30,8 @@
 	atomic_int _enqueuedBuffers;
 	AudioQueueBufferRef _buffers[NumBuffers];
 	int _bufferWritePointer;
+
+	unsigned int _numChannels;
 }
 
 #pragma mark - Status
@@ -49,6 +51,7 @@
 		atomic_store_explicit(&_enqueuedBuffers, 0, memory_order_relaxed);
 
 		_samplingRate = samplingRate;
+		_numChannels = isStereo ? 2 : 1;
 
 		// Determine preferred buffer size as being the first power of two
 		// not less than 1/100th of a second.
@@ -138,20 +141,20 @@
 
 	// Allocate future audio buffers.
 	[_queueLock lock];
-		const size_t bufferBytes = self.bufferSize * sizeof(int16_t);
+		const size_t bufferBytes = self.bufferSize * sizeof(int16_t) * _numChannels;
 		for(size_t c = 0; c < NumBuffers; c++) {
 			if(_buffers[c]) {
 				OSSGuard(AudioQueueFreeBuffer(_audioQueue, _buffers[c]));
 			}
 
-			OSSGuard(AudioQueueAllocateBuffer(_audioQueue, (UInt32)bufferBytes * 2, &_buffers[c]));
+			OSSGuard(AudioQueueAllocateBuffer(_audioQueue, (UInt32)bufferBytes, &_buffers[c]));
 			_buffers[c]->mAudioDataByteSize = (UInt32)bufferBytes;
 		}
 	[_queueLock unlock];
 }
 
 - (void)enqueueAudioBuffer:(const int16_t *)buffer {
-	const size_t bufferBytes = self.bufferSize * sizeof(int16_t);
+	const size_t bufferBytes = self.bufferSize * sizeof(int16_t) * _numChannels;
 
 	// Don't enqueue more than the allowed number of future buffers,
 	// to ensure not too much latency accrues.
diff --git a/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm b/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm
index 295262a60..cd2a28075 100644
--- a/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm	
+++ b/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm	
@@ -176,7 +176,7 @@ struct ActivityObserver: public Activity::Observer {
 }
 
 - (void)speaker:(Outputs::Speaker::Speaker *)speaker didCompleteSamples:(const int16_t *)samples length:(int)length {
-	assert(NSUInteger(length) == self.audioQueue.bufferSize);
+	assert(NSUInteger(length) == self.audioQueue.bufferSize*(speaker->get_is_stereo() ? 2 : 1));
 	[self.audioQueue enqueueAudioBuffer:samples];
 }
 
diff --git a/Outputs/Speaker/Implementation/LowpassSpeaker.hpp b/Outputs/Speaker/Implementation/LowpassSpeaker.hpp
index d9d6aaa46..2d31d97a7 100644
--- a/Outputs/Speaker/Implementation/LowpassSpeaker.hpp
+++ b/Outputs/Speaker/Implementation/LowpassSpeaker.hpp
@@ -239,9 +239,9 @@ template <typename ConcreteT, bool is_stereo> class LowpassBase: public Speaker
 		}
 
 	protected:
-		void process(size_t length) {
+		bool process(size_t length) {
 			const auto delegate = delegate_.load(std::memory_order::memory_order_relaxed);
-			if(!delegate) return;
+			if(!delegate) return false;
 
 			const int scale = static_cast<ConcreteT *>(this)->get_scale();
 
@@ -286,6 +286,8 @@ template <typename ConcreteT, bool is_stereo> class LowpassBase: public Speaker
 					// TODO: input rate is less than output rate.
 				break;
 			}
+
+			return true;
 		}
 };
 
@@ -334,8 +336,11 @@ template <bool is_stereo> class PushLowpass: public LowpassBase<PushLowpass<is_s
 		*/
 		void push(const int16_t *buffer, size_t length) {
 			buffer_ = buffer;
-			process(length);
-			assert(buffer_ == buffer + (length * (1 + is_stereo)));
+#ifndef NDEBUG
+			const bool did_process =
+#endif
+				process(length);
+			assert(!did_process || buffer_ == buffer + (length * (1 + is_stereo)));
 		}
 };