Manual for Loopback is located at the help menu or with cmd-?.
In MegaSeg set output to loopback and not speakers.
In stereotool set input to loopback and output to the output you want the sound to come from.
Do you have a mixer in the chain or do you do all "in the mac" and do want to get to transmitter directly from the mac?
For some reason I can't get rid of the reverb on the audio. I've now tried this on two different Mac's and in each case, even with these settings, I still get echo in the background. I've even set the audio outputs down way low but that still doesn't solve the problem.
Is it possible that some computers just won't work with Loopback? I can get everything to work perfectly without Loopback if I use separate computers for MegaSeg and Stereo Tool. Would prefer to use a single computer for obvious reasons but unless I can get the noise issue resolved, I won't be able to use Loopback.