[tptman]

You actually can record a processed signal into PTfree. First add an aux track (CTRL-Shift N). Set the input on that track to Input L or R, depending on what input on your sound card you're recording from. Set you output to Bus 1. Now insert the compressor plug-in on the Aux track. Go to you vocal track (the actual audio track). Set your input to bus 1 and your output to Output L or R. Now everything you record will go throught the Aux track with plugs before going to the audio track and being laid down on your hard drive.

This can work well to use as a bit of a limiter, but be judicious, don't overdo it as it can't be fixed later. It is also wise not to do much else to the signal, especially reverb, etc. for the same reason.