@danswartz:
The default location for these is in sip_general_additional.conf, but you tweak them in sip_general_custom.conf. Like this:
tos_sip=0
tos_audio=0
NB: this is for a freepbx-based system. If yours is not, you need to figure out where to set these for your setup.
Been looking for this solution for a long time. Thanks. Im on the PBXInAFlash asterisk flavor….