diff --git a/gearslip/src/main/java/app/seb3thehacker/gearslip/audio/AudioLink.kt b/gearslip/src/main/java/app/seb3thehacker/gearslip/audio/AudioLink.kt
index 675ab79..51f73fc 100644
--- a/gearslip/src/main/java/app/seb3thehacker/gearslip/audio/AudioLink.kt
+++ b/gearslip/src/main/java/app/seb3thehacker/gearslip/audio/AudioLink.kt
@@ -233,7 +233,19 @@ class AudioLink(
         startStream()
     }
 
+    /**
+     * Guards starting and stopping. [start] starts the stream at once for head units that never
+     * answer the focus request, and the car's answer arrives on another thread and starts it
+     * too: without this both got through, so the car got Start twice and two AAC encoders, and a
+     * 2014 head unit dropped the connection on the first audio.
+     */
+    private val startLock = Any()
+
     private fun startStream() {
+        synchronized(startLock) { startStreamLocked() }
+    }
+
+    private fun startStreamLocked() {
         if (!ready || started) return
         sendOnChannel(
             MSG_START,
@@ -252,6 +264,10 @@ class AudioLink(
     }
 
     override fun stop() {
+        synchronized(startLock) { stopLocked() }
+    }
+
+    private fun stopLocked() {
         if (!started) return
         started = false
         synchronized(ackLock) { ackLock.notifyAll() }
diff --git a/gearslip/src/main/java/app/seb3thehacker/gearslip/car/DirectionsVoice.kt b/gearslip/src/main/java/app/seb3thehacker/gearslip/car/DirectionsVoice.kt
index 5e5960d..4aaeda0 100644
--- a/gearslip/src/main/java/app/seb3thehacker/gearslip/car/DirectionsVoice.kt
+++ b/gearslip/src/main/java/app/seb3thehacker/gearslip/car/DirectionsVoice.kt
@@ -87,16 +87,26 @@ object DirectionsVoice {
         running = false
     }
 
+    /** Why the last turn wasn't spoken, so the log says it once rather than every tick. */
+    private var silentBecause: String? = null
+
+    private fun quiet(reason: String) {
+        if (silentBecause == reason) return
+        silentBecause = reason
+        GearslipLog.i("guidance: not speaking - $reason")
+    }
+
     private fun tick() {
-        if (!CarSettings.speakDirections.value) return
         val turn = NavTurn.current()
         if (turn == null) {
             turnKey = null
             return
         }
-        if (turn.rerouting) return
+        if (!CarSettings.speakDirections.value) return quiet("Spoken directions is off in the car's Settings")
+        if (turn.rerouting) return quiet("the map app is rerouting")
         val step = turn.step
-        val instruction = instruction(step) ?: return
+        val instruction = instruction(step) ?: return quiet("the map app gave this turn no words")
+        silentBecause = null
         val meters = turn.distance?.let(NavTurn::toMeters)
         val close = (turn.seconds != null && turn.seconds <= NEAR_SECONDS) || (meters != null && meters <= NEAR_METERS)