for the life of me, I can't get audio. reading through the mailing list and manual, it looks like it should just work with RDP. I'm running guacd and guac client on the same server (centos 7). fyi.. I'm a Linux newbie..so its possible I made a mistake in configuration or building somewhere. Any thoughts?
What O/S are you connecting to? Have you verified that audio works correctly to a desktop RDP client? No policies that would be preventing it?
There are some things you have to verify to make sure audio redirection is properly configured for Guacamole - you need to make sure the plugin libraries (/path/to/guac/lib/freerdp/guac*.so) are linked into the FreeRDP directory (/usr/lib64/freerdp on CentOS 7).