diff --git a/gumble/gumble/integration_audio_test.go b/gumble/gumble/integration_audio_test.go
index e578e2a..bc24a55 100644
--- a/gumble/gumble/integration_audio_test.go
+++ b/gumble/gumble/integration_audio_test.go
@@ -27,7 +27,13 @@ func (l *integrationAudioListener) OnAudioStream(e *gumble.AudioStreamEvent) {
 
 // TestLocalMumbleAudioRoundTrip sends generated 440 Hz audio through a real
 // local Mumble server and requires the other client to decode non-silent PCM.
-func TestLocalMumbleAudioRoundTrip(t *testing.T) {
+func TestLocalMumbleAudioRoundTrip(t *testing.T) { testLocalMumbleAudioRoundTrip(t, false) }
+
+// Regression: TCP tunnel fallback must remain usable when UDP is deliberately
+// disabled or blocked, rather than silently dropping valid audio.
+func TestLocalMumbleTCPAudioFallback(t *testing.T) { testLocalMumbleAudioRoundTrip(t, true) }
+
+func testLocalMumbleAudioRoundTrip(t *testing.T, disableUDP bool) {
 	if os.Getenv("BARNARD_MUMBLE_INTEGRATION") != "1" {
 		t.Skip("set BARNARD_MUMBLE_INTEGRATION=1")
 	}
@@ -35,7 +41,7 @@ func TestLocalMumbleAudioRoundTrip(t *testing.T) {
 		c := gumble.NewConfig()
 		c.Address = "localhost:64738"
 		c.Username = name
-		c.DisableUDP = false
+		c.DisableUDP = disableUDP
 		return c
 	}
 	tlsConfig := &tls.Config{InsecureSkipVerify: true}
@@ -57,7 +63,11 @@ func TestLocalMumbleAudioRoundTrip(t *testing.T) {
 		t.Fatal("no negotiated audio encoder")
 	}
 	time.Sleep(1500 * time.Millisecond)
-	if !sender.UDPActive() || !receiver.UDPActive() {
+	if disableUDP {
+		if sender.UDPActive() || receiver.UDPActive() {
+			t.Fatal("UDP activated despite TCP-only configuration")
+		}
+	} else if !sender.UDPActive() || !receiver.UDPActive() {
 		t.Fatalf("native UDP did not become active: sender=%v receiver=%v", sender.UDPActive(), receiver.UDPActive())
 	}
 	frame := make([]int16, sendConfig.AudioFrameSize())