redirect application for recording

[Linux for blind general discussion]

I wish to record something from firefox without recording all the system audio, such as orca. I found this thread,

https://askubuntu.com/questions/60837/record-a-programs-output-with-pulseaudio

But this looks like it redirects the entire system audio output to the sink.

Any help in trying to record with sox or something from firefox would be appreciated.