diff --git a/Plugins/MIDI/MIDI.xcodeproj/project.pbxproj b/Plugins/MIDI/MIDI.xcodeproj/project.pbxproj
index 7fe282cb3..472d06a0c 100644
--- a/Plugins/MIDI/MIDI.xcodeproj/project.pbxproj
+++ b/Plugins/MIDI/MIDI.xcodeproj/project.pbxproj
@@ -37,6 +37,7 @@
 		83B06722180D70FE008E3612 /* MIDIDecoder.mm in Sources */ = {isa = PBXBuildFile; fileRef = 83B06721180D70FE008E3612 /* MIDIDecoder.mm */; };
 		83C35702180EDB74007E9DF0 /* MIDIContainer.mm in Sources */ = {isa = PBXBuildFile; fileRef = 83C35700180EDB74007E9DF0 /* MIDIContainer.mm */; };
 		83C35705180EDD1C007E9DF0 /* MIDIMetadataReader.mm in Sources */ = {isa = PBXBuildFile; fileRef = 83C35703180EDD1C007E9DF0 /* MIDIMetadataReader.mm */; };
+		83E83F7B2D9654470054365C /* Accelerate.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 83E83F7A2D9654470054365C /* Accelerate.framework */; };
 		83E973471C4378880007F413 /* AUPlayer.mm in Sources */ = {isa = PBXBuildFile; fileRef = 83E973451C4378880007F413 /* AUPlayer.mm */; };
 		83EA54232A6A6CF400CD0580 /* libbass_mpc.dylib in CopyFiles */ = {isa = PBXBuildFile; fileRef = 83EA54212A6A6CE200CD0580 /* libbass_mpc.dylib */; settings = {ATTRIBUTES = (CodeSignOnCopy, ); }; };
 /* End PBXBuildFile section */
@@ -155,6 +156,7 @@
 		83C35701180EDB74007E9DF0 /* MIDIContainer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MIDIContainer.h; sourceTree = "<group>"; };
 		83C35703180EDD1C007E9DF0 /* MIDIMetadataReader.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = MIDIMetadataReader.mm; sourceTree = "<group>"; };
 		83C35704180EDD1C007E9DF0 /* MIDIMetadataReader.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MIDIMetadataReader.h; sourceTree = "<group>"; };
+		83E83F7A2D9654470054365C /* Accelerate.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Accelerate.framework; path = System/Library/Frameworks/Accelerate.framework; sourceTree = SDKROOT; };
 		83E973451C4378880007F413 /* AUPlayer.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = AUPlayer.mm; sourceTree = "<group>"; };
 		83E973461C4378880007F413 /* AUPlayer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AUPlayer.h; sourceTree = "<group>"; };
 		83EA54212A6A6CE200CD0580 /* libbass_mpc.dylib */ = {isa = PBXFileReference; lastKnownFileType = "compiled.mach-o.dylib"; name = libbass_mpc.dylib; path = ../../ThirdParty/BASS/libbass_mpc.dylib; sourceTree = "<group>"; };
@@ -168,6 +170,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				834D190C2D7F954100F13B89 /* CogAudio.framework in Frameworks */,
+				83E83F7B2D9654470054365C /* Accelerate.framework in Frameworks */,
 				8398F2E01C438C7D00EB9639 /* AudioUnit.framework in Frameworks */,
 				83686AB11C5C783000671C7A /* CoreAudioKit.framework in Frameworks */,
 				83B06701180D5747008E3612 /* midi_processing.framework in Frameworks */,
@@ -281,6 +284,7 @@
 		83B06689180D5668008E3612 /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				83E83F7A2D9654470054365C /* Accelerate.framework */,
 				834D190B2D7F954100F13B89 /* CogAudio.framework */,
 				83686AB01C5C783000671C7A /* CoreAudioKit.framework */,
 				83686AAE1C5C780500671C7A /* AudioToolbox.framework */,
diff --git a/Plugins/MIDI/MIDI/AUPlayer.mm b/Plugins/MIDI/MIDI/AUPlayer.mm
index 464c36981..aaedd1f9a 100644
--- a/Plugins/MIDI/MIDI/AUPlayer.mm
+++ b/Plugins/MIDI/MIDI/AUPlayer.mm
@@ -1,6 +1,8 @@
-#include "AUPlayer.h"
+#import "AUPlayer.h"
 
-#include <stdlib.h>
+#import <stdlib.h>
+
+#import <Accelerate/Accelerate.h>
 
 #define SF2PACK
 
@@ -82,29 +84,33 @@ void AUPlayer::send_sysex_time(const uint8_t *data, size_t size, size_t port, un
 }
 
 void AUPlayer::render(float *out, unsigned long count) {
-	float *ptrL, *ptrR;
-	memset(out, 0, count * sizeof(float) * 2);
+	const float *ptrL, *ptrR;
+	bzero(out, count * sizeof(float) * 2);
 	while(count) {
 		UInt32 numberFrames = count > BLOCK_SIZE ? BLOCK_SIZE : (UInt32)count;
 
 		for(unsigned long i = 0; i < 3; ++i) {
 			AudioUnitRenderActionFlags ioActionFlags = 0;
 
+			bufferList->mNumberBuffers = 2;
 			for(unsigned long j = 0; j < 2; j++) {
 				bufferList->mBuffers[j].mNumberChannels = 1;
 				bufferList->mBuffers[j].mDataByteSize = (UInt32)(numberFrames * sizeof(float));
 				bufferList->mBuffers[j].mData = audioBuffer + j * BLOCK_SIZE;
-				memset(bufferList->mBuffers[j].mData, 0, numberFrames * sizeof(float));
+				bzero(bufferList->mBuffers[j].mData, numberFrames * sizeof(float));
 			}
 
 			AudioUnitRender(samplerUnit[i], &ioActionFlags, &mTimeStamp, 0, numberFrames, bufferList);
 
-			ptrL = (float *)bufferList->mBuffers[0].mData;
-			ptrR = (float *)bufferList->mBuffers[1].mData;
-			for(unsigned long j = 0; j < numberFrames; ++j) {
-				out[j * 2 + 0] += ptrL[j];
-				out[j * 2 + 1] += ptrR[j];
-			}
+			ptrL = (const float *)bufferList->mBuffers[0].mData;
+			ptrR = (const float *)bufferList->mBuffers[1].mData;
+			size_t numBytesL = bufferList->mBuffers[0].mDataByteSize;
+			size_t numBytesR = bufferList->mBuffers[1].mDataByteSize;
+			size_t numBytes = MIN(numBytesL, numBytesR);
+			size_t numFrames = numBytes / sizeof(float);
+			numFrames = MIN(numFrames, numberFrames);
+			vDSP_vadd(ptrL, 1, out, 2, out, 2, numFrames);
+			vDSP_vadd(ptrR, 1, out + 1, 2, out + 1, 2, numFrames);
 		}
 
 		out += numberFrames * 2;
@@ -214,7 +220,7 @@ static OSStatus renderCallback(void *inRefCon, AudioUnitRenderActionFlags *ioAct
 			int k = inNumberFrames * sizeof(float);
 			if(k > ioData->mBuffers[i].mDataByteSize)
 				k = ioData->mBuffers[i].mDataByteSize;
-			memset(ioData->mBuffers[i].mData, 0, k);
+			bzero(ioData->mBuffers[i].mData, k);
 		}
 	}
 
@@ -222,7 +228,7 @@ static OSStatus renderCallback(void *inRefCon, AudioUnitRenderActionFlags *ioAct
 }
 
 bool AUPlayer::startup() {
-	if(bufferList) return true;
+	if(initialized) return true;
 
 	AudioComponentDescription cd = { 0 };
 	cd.componentType = kAudioUnitType_MusicDevice;
diff --git a/Plugins/MIDI/MIDI/MIDIPlayer.cpp b/Plugins/MIDI/MIDI/MIDIPlayer.cpp
index ce3a125b8..57934f8a3 100644
--- a/Plugins/MIDI/MIDI/MIDIPlayer.cpp
+++ b/Plugins/MIDI/MIDI/MIDIPlayer.cpp
@@ -148,8 +148,8 @@ unsigned long MIDIPlayer::Play(float *out, unsigned long count) {
 			for(; uStreamPosition < stream_end; uStreamPosition++) {
 				const midi_stream_event &me = mStream.at(uStreamPosition);
 
-				unsigned long samples_todo = me.m_timestamp - uTimeCurrent - into_block;
-				if(samples_todo) {
+				ssize_t samples_todo = me.m_timestamp - uTimeCurrent - into_block;
+				if(samples_todo > 0) {
 					if(samples_todo > count - done) {
 						uSamplesRemaining = samples_todo - (count - done);
 						samples_todo = count - done;
@@ -167,12 +167,14 @@ unsigned long MIDIPlayer::Play(float *out, unsigned long count) {
 				}
 
 				if(needs_block_size) {
-					into_block += samples_todo;
-					while(into_block >= needs_block_size) {
-						render(out + done * 2, needs_block_size);
-						done += needs_block_size;
-						into_block -= needs_block_size;
-						uTimeCurrent += needs_block_size;
+					if(samples_todo > 0) {
+						into_block += samples_todo;
+						while(into_block >= needs_block_size) {
+							render(out + done * 2, needs_block_size);
+							done += needs_block_size;
+							into_block -= needs_block_size;
+							uTimeCurrent += needs_block_size;
+						}
 					}
 					send_event_time_filtered(me.m_event, into_block);
 				} else