I had a flash of SMRT yesterday working on the audio for an artist's talk I taped last week. I had...

I had a flash of SMRT yesterday working on the audio for an artist's talk I taped last week. I had the artist's voice recorded on a microphone and another mic set up to get the ambient sound from the room to so I could get the audience questions and comments. Problem was that there was also an amplified speaker in the back of the room so I couldn't just use both tracks as is because the amplified speaker was an annoying echo, lagging ever so slightly behind the sound from the mic, and was a lot louder than all the other sound in the room. Cutting back and forth was a pain and sounded weird since the audio from the mic sounded dubbed (no room echo) compared to people speaking in the room. So I needed to remove the sound from the amplified speaker only. The solution was to take the sound from the podium mic, offset it ever so slightly to match the tiny lag, then invert the waveform and add it to the room ambient waveform, leaving me with the voices of the audience and the ambient echo in the room so the podium mic no longer sounded dubbed in.