Update shairport-sync.conf

scripts/shairport-sync.conf

@@ -25,6 +25,7 @@ general =
 // log_verbosity = 0; // "0" means no debug verbosity, "3" is most verbose.
 // ignore_volume_control = "no"; // set this to "yes" if you want the volume to be at 100% no matter what the source's volume control is set to.
 // volume_range_db = 60 ; // use this to set the range, in dB, you want between the maximum volume and the minimum volume. Range is 30 to 150 dB. Leave it commented out to use mixer's native range.
+// volume_max_db = 0 ; // use this to set the maximum volume, in dB, you wish to use, which must be in the attenuator's range (0 – -98 for software attenuator). Leave it commented out to use mixer's maximum volume.
 // regtype = "_raop._tcp"; // Use this advanced setting to set the service type and transport to be advertised by Zeroconf/Bonjour. Default is "_raop._tcp".
 // playback_mode = "stereo"; // This can be "stereo", "mono", "reverse stereo", "both left" or "both right". Default is "stereo".
 // alac_decoder = "hammerton"; // This can be "hammerton" or "apple". This advanced setting allows you to choose