diff --git a/Makefile.mk b/Makefile.mk
index db6c10fb..b0428a53 100644
--- a/Makefile.mk
+++ b/Makefile.mk
@@ -279,10 +279,10 @@ x11test x11test-v: $(x11test/files.json) $(lib/AnklangSynthEngine)
 	$Q mkdir -p $>/x11test/
 	$Q $(CP) $(x11test/files.json) $>/x11test/
 	$Q cd $>/x11test/ \
-	&& { test "$@" == x11test-v && H=-v || H= ; } \
+	&& { test "$@" == x11test-v && OPT=-v || OPT=-p ; } \
 	&& for json in *.json ; do \
 		echo "$$json" \
-		&& $(abspath x11test/replay.sh) $$H $$json || exit $$? \
+		&& $(abspath x11test/replay.sh) $$OPT $$json || exit $$? \
 	 ; done
 CLEANDIRS += $>/x11test/
 .PHONY: x11test x11test-v
diff --git a/x11test/replay.sh b/x11test/replay.sh
index 4301fbb3..fea3f6db 100755
--- a/x11test/replay.sh
+++ b/x11test/replay.sh
@@ -8,10 +8,12 @@ X11TEST="${SCRIPTNAME%/*}"
 
 # parse CLI
 OPTS=-w
+NODEVS="-P null -M null"
 while [[ "${1:-}" = -* ]] ; do
   case "$1" in
     -v)		OPTS=-v ;;
     -w)		OPTS=-w ;;
+    -p)		NODEVS= ;;
     -h)		cat <<-_EOF
 	Usage: replay.sh [OPTIONS] <play.json>
 	Replay a DevTools recording in Electron via Puppetteer
@@ -19,6 +21,7 @@ while [[ "${1:-}" = -* ]] ; do
 	  -h		Display brief usage
 	  -v		Use virtual X11 server for headless recording
 	  -w		Use nested X11 window as server
+	  -p		Use realy PCM/MIDI devices
 _EOF
 		exit 0 ;;
     *)		die "unknown option: $1"
@@ -39,7 +42,7 @@ cp $X11TEST/epuppeteer.mjs .
 
 # Start Anklang engine
 test -x $X11TEST/../out/lib/AnklangSynthEngine || die "missing executable:" AnklangSynthEngine
-$X11TEST/../out/lib/AnklangSynthEngine &
+$X11TEST/../out/lib/AnklangSynthEngine $NODEVS &
 
 # Replay in ELectron and record X11 session
 EXITSTATUS=0