Includ note about audio_backend_buffer_desired_length in TROUBLESHOOTING.md

diff --git a/TROUBLESHOOTING.md b/TROUBLESHOOTING.md
index 8a4e14e54de02b5f9d3279f0a0bd177f56fb812f..fd500e604c49d85650fefb1d760ef47d618b659b 100644 (file)
--- a/TROUBLESHOOTING.md
+++ b/TROUBLESHOOTING.md
@@ -231,3 +231,20 @@ This will then be used by default by Shairport-Sync and any other applications u
 Note that some distributions (such as Volumio 2) don't use an asound.conf file by default, they instead specify the hardware details directly in '/etc/mpd.conf' files so some more in-depth modification is needed to override this.
 
 (Note: not tested by Mike B.)
+
+### Buffer underflow to audio backend
+
+**Problem **
+
+Audio may seem to pause or drop for several seconds. iOS devices may regularly disconnect altogether and display an error message. This may be caused by a combination of factors listed above such as slow WiFi or limited resources on the device running Shairport Sync.
+
+**Possible Solution **
+
+If none of the above steps completely remove the issue, try increasing the audio backend buffer setting in the backend section of shairport-sync.conf. (This section may vary depending on the value of the "output_backend" setting.)
+
+For example:
+
+````
+audio_backend_buffer_desired_length = 19845;
+````
+Is triple the default for the ALSA backend and effectively solves the above issue with a Pi Zero on a busy network.