diff --git a/README.md b/README.md
index 5fa213c..bb3b266 100644
--- a/README.md
+++ b/README.md
@@ -133,6 +133,8 @@ Only valid on SDL mode
         emulate a green phosphor monitor instead of a NTSC color TV. Use F6 to toggle.
   -panicss
         panic if a not implemented softswitch is used
+  -profile
+        generate profile trace to analyse with pprof
   -rom string
         main rom file (default "<internal>/Apple2_Plus.rom")
   -saturnCardSlot int
diff --git a/apple2.go b/apple2.go
index 7ebab0b..f4c6e40 100644
--- a/apple2.go
+++ b/apple2.go
@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/ivanizag/apple2/core6502"
+	"github.com/pkg/profile"
 )
 
 // Apple2 represents all the components and state of the emulated machine
@@ -25,6 +26,7 @@ type Apple2 struct {
 	isColor             bool
 	fastMode            bool
 	fastRequestsCounter int
+	profile             bool
 }
 
 const (
@@ -37,6 +39,12 @@ const maxWaitDuration = 100 * time.Millisecond
 
 // Run starts the Apple2 emulation
 func (a *Apple2) Run() {
+	if a.profile {
+		// See the log with:
+		//    go tool pprof --pdf ~/go/bin/apple2sdl /tmp/profile329536248/cpu.pprof > profile.pdf
+		defer profile.Start().Stop()
+	}
+
 	// Start the processor
 	a.cpu.Reset()
 	referenceTime := time.Now()
@@ -50,6 +58,9 @@ func (a *Apple2) Run() {
 		for commandsPending {
 			select {
 			case command := <-a.commandChannel:
+				if command == CommandKill {
+					return
+				}
 				a.executeCommand(command)
 			default:
 				commandsPending = false
@@ -73,6 +84,10 @@ func (a *Apple2) Run() {
 	}
 }
 
+func (a *Apple2) setProfile(value bool) {
+	a.profile = value
+}
+
 const (
 	// CommandToggleSpeed toggles cpu speed between full speed and actual Apple II speed
 	CommandToggleSpeed = iota + 1
@@ -88,6 +103,8 @@ const (
 	CommandNextCharGenPage
 	// CommandToggleCPUTrace toggle tracing of CPU execution
 	CommandToggleCPUTrace
+	// CommandKill stops the cpu execution loop
+	CommandKill
 )
 
 // SendCommand enqueues a command to the emulator thread
diff --git a/apple2main.go b/apple2main.go
index 32a6a6c..70e0c3a 100644
--- a/apple2main.go
+++ b/apple2main.go
@@ -88,6 +88,11 @@ func MainApple() *Apple2 {
 		"2plus",
 		"set base model. Models available 2plus, 2e, base64a",
 	)
+	profile := flag.Bool(
+		"profile",
+		false,
+		"generate profile trace to analyse with pprof",
+	)
 	flag.Parse()
 
 	var a *Apple2
@@ -138,6 +143,7 @@ func MainApple() *Apple2 {
 	a.cpu.SetTrace(*traceCPU)
 	a.io.setTrace(*traceSS)
 	a.io.setPanicNotImplemented(*panicSS)
+	a.setProfile(*profile)
 
 	// Load ROM if not loaded already
 	if *romFile != "" {
diff --git a/apple2sdl/main.go b/apple2sdl/main.go
index 4166e64..5c81b4b 100644
--- a/apple2sdl/main.go
+++ b/apple2sdl/main.go
@@ -43,6 +43,7 @@ func SDLRun(a *apple2.Apple2) {
 		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
 			switch t := event.(type) {
 			case *sdl.QuitEvent:
+				a.SendCommand(apple2.CommandKill)
 				running = false
 			case *sdl.KeyboardEvent:
 				//fmt.Printf("[%d ms] Keyboard\ttype:%d\tsym:%c\tmodifiers:%d\tstate:%d\trepeat:%d\n",
diff --git a/apple2sdl/sdlSpeaker.go b/apple2sdl/sdlSpeaker.go
index df131cc..d26adcf 100644
--- a/apple2sdl/sdlSpeaker.go
+++ b/apple2sdl/sdlSpeaker.go
@@ -21,6 +21,7 @@ const (
 	sampleDurationCycles = 1000000 * apple2.CpuClockMhz / samplingHz
 	// each sample on the sound stream is 21.31 cpu cycles approx
 	maxOutOfSyncMs = 2000
+	decayLevel     = 128
 )
 
 type sdlSpeaker struct {
@@ -28,6 +29,7 @@ type sdlSpeaker struct {
 	pendingClicks []uint64
 	lastCycle     uint64
 	lastState     bool
+	lastLevel     C.Uint8
 }
 
 /*
@@ -40,6 +42,7 @@ func newSDLSpeaker() *sdlSpeaker {
 	var s sdlSpeaker
 	s.clickChannel = make(chan uint64, bufferSize)
 	s.pendingClicks = make([]uint64, 0, bufferSize)
+	s.lastLevel = decayLevel // Mid position to avoid starting clicks.
 	return &s
 }
 
@@ -55,6 +58,7 @@ func stateToLevel(state bool) C.Uint8 {
 	return 0
 }
 
+// SpeakerCallback is called to get more sound buffer data
 //export SpeakerCallback
 func SpeakerCallback(userdata unsafe.Pointer, stream *C.Uint8, length C.int) {
 	s := theSDLSpeaker
@@ -90,7 +94,7 @@ func SpeakerCallback(userdata unsafe.Pointer, stream *C.Uint8, length C.int) {
 
 	// Build wave
 	var i, p int
-	level := stateToLevel(s.lastState)
+	level := s.lastLevel
 	for p = 0; p < len(s.pendingClicks); p++ {
 		cycle := s.pendingClicks[p]
 		if cycle < s.lastCycle {
@@ -119,10 +123,26 @@ func SpeakerCallback(userdata unsafe.Pointer, stream *C.Uint8, length C.int) {
 		}
 	}
 
+	// If the buffer is empty lets decay the signal
+	if i == 0 {
+		for level != decayLevel && i < bufferSize {
+			if i%100 == 0 {
+				if level > decayLevel {
+					level--
+				} else {
+					level++
+				}
+			}
+			buf[i] = level
+			i++
+		}
+	}
+
 	// Complete the buffer if needed
 	for b := i; b < bufferSize; b++ {
 		buf[b] = level
 	}
+	s.lastLevel = level
 
 	// Remove processed clicks, store the rest for later
 	remainingClicks := len(s.pendingClicks) - p
diff --git a/memoryManager.go b/memoryManager.go
index 56360f3..32f02bd 100644
--- a/memoryManager.go
+++ b/memoryManager.go
@@ -33,7 +33,7 @@ const (
 	ioC8Off uint16 = 0xCFFF
 )
 
-func (mmu *memoryManager) access(address uint16, activeMemory [256]memoryHandler) memoryHandler {
+func (mmu *memoryManager) access(address uint16, activeMemory *[256]memoryHandler) memoryHandler {
 	if address == ioC8Off {
 		mmu.resetSlotExpansionRoms()
 	}
@@ -54,7 +54,7 @@ func (mmu *memoryManager) access(address uint16, activeMemory [256]memoryHandler
 
 // Peek returns the data on the given address
 func (mmu *memoryManager) Peek(address uint16) uint8 {
-	mh := mmu.access(address, mmu.activeMemoryRead)
+	mh := mmu.access(address, &mmu.activeMemoryRead)
 	if mh == nil {
 		return 0xf4 // Or some random number
 	}
@@ -63,7 +63,7 @@ func (mmu *memoryManager) Peek(address uint16) uint8 {
 
 // Poke sets the data at the given address
 func (mmu *memoryManager) Poke(address uint16, value uint8) {
-	mh := mmu.access(address, mmu.activeMemoryWrite)
+	mh := mmu.access(address, &mmu.activeMemoryWrite)
 	if mh == nil {
 		return
 	}