diff --git a/README.md b/README.md
index ce54607d..181008e0 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,9 @@ Shairport Sync allows you to synchronise the audio coming from all your devices.
 
 Shairport Sync is a pretty substantial rewrite of Shairport 1.0 by James Laird and others -- please see https://github.com/abrasive/shairport/blob/master/README.md#contributors-to-version-1x for a list of the contributors to Shairport 1.x and Shairport 0.x. From a "heritage" point of view, Shairport Sync is a fork of Shairport 1.0 and the active branch is called Shairport 2.0.
 
-Shairport Sync is still experimental, and only works with Linux and ALSA. Some of the support files, e.g. PKGBUILD and shairport.service files, are out of date.
+Shairport Sync is still experimental, and only works with Linux and ALSA. The sound card you use must be capable of working with 44,100 samples per second interleaved PCM stereo (you'll get a message in the logfile if there's a problem).
+
+Some of the support files, e.g. PKGBUILD and shairport.service files, are out of date.
 
 What is Shairport?
 ----------