diff --git a/Cocoa/Document.m b/Cocoa/Document.m
index 0418c56..03d4acd 100644
--- a/Cocoa/Document.m
+++ b/Cocoa/Document.m
@@ -309,16 +309,17 @@ static void audioCallback(GB_gameboy_t *gb, GB_sample_t *sample)
     GB_set_sample_rate(&gb, 96000);
     self.audioClient = [[GBAudioClient alloc] initWithRendererBlock:^(UInt32 sampleRate, UInt32 nFrames, GB_sample_t *buffer) {
         [audioLock lock];
-        if (stopping) {
-            memset(buffer, 0, nFrames * sizeof(*buffer));
-            [audioLock unlock];
-        }
         
         if (audioBufferPosition < nFrames) {
             audioBufferNeeded = nFrames;
             [audioLock wait];
         }
         
+        if (stopping) {
+            memset(buffer, 0, nFrames * sizeof(*buffer));
+            [audioLock unlock];
+        }
+        
         if (audioBufferPosition >= nFrames && audioBufferPosition < nFrames + 4800) {
             memcpy(buffer, audioBuffer, nFrames * sizeof(*buffer));
             memmove(audioBuffer, audioBuffer + nFrames, (audioBufferPosition - nFrames) * sizeof(*buffer));
@@ -376,6 +377,7 @@ static void audioCallback(GB_gameboy_t *gb, GB_sample_t *sample)
     }
     [audioLock lock];
     stopping = true;
+    [audioLock signal];
     [audioLock unlock];
     running = false;
     while (stopping);