diff --git a/audio/cava/Makefile b/audio/cava/Makefile
--- a/audio/cava/Makefile
+++ b/audio/cava/Makefile
@@ -1,5 +1,6 @@
 PORTNAME=	cava
 DISTVERSION=	0.10.1
+PORTREVISION=	1
 CATEGORIES=	audio
 
 MAINTAINER=	vendion@gmail.com
@@ -23,6 +24,7 @@
 PLIST_FILES=	bin/cava
 PORTDOCS=	README.md
 PORTEXAMPLES=	config
+SUB_FILES=	pkg-message
 
 OPTIONS_DEFINE=		DOCS EXAMPLES VT
 OPTIONS_DEFAULT=	GLSL JACK NCURSES OSS PORTAUDIO PULSEAUDIO SDL SNDIO VT
diff --git a/audio/cava/files/pkg-message.in b/audio/cava/files/pkg-message.in
new file mode 100644
--- /dev/null
+++ b/audio/cava/files/pkg-message.in
@@ -0,0 +1,16 @@
+[
+{ type: install
+  message: <<EOM
+If you want to visualize your currently played back audio then be aware that the
+audio backends OSS and sndio can't feed the outgoing audio directly into CAVA
+without further setup:
+
+* For OSS you need to use audio/virtual_oss in order to create a loopback
+  audio device.
+* For sndio you need to start a sndio server and create a monitoring
+  sub-device.
+
+Please see %%DOCSDIR%%/README.md for additional help and instructions.
+EOM
+}
+]