I am NOT an audio professional! So I came to the place where they live to get answers to my question. I am editing a multicamera shoot in which the wireless mics failed (don't get me started!!!). The on camera mic were picking up audio on channels 3/4. I have this audio that I can use to finish the video.
It was in a large room so the audio has this soft, high, tin like sound. I have tried to use an EQ to add some low and mids but I get more of a mud sound than clean. It is introducing alot of noise.
"soft high thin" Hmm, I'm guessing it's real "roomy." You could post ca lip somewhere and let us know where it is so we can hear it, but my guess is you're pretty hosed. There really is no filter or processsor that can take away room sound from a camera mic.
You can try to roll of the top a bit 'cause a lot of room sound has reflections. Try notching the 1kHz to 3 kHz up a bit. A lot of voice energy is in that area.
I've gotten several calls from a local studio to fix audio in post that got screwed up in production. There's a lot of tricks an audio pro with the right set of tools could try, but it's not going to be pretty. It'll be better than awful, but still bad.
Just a hint with EQ. You'll get the best results by attenuating (cutting) trouble frequencies rather than by trying to boost missing frequencies. You can try to boost the low to mid freqs to beef up the voices, but you'll just make a muddy mess with the room. Now if you could get a good sample of room tone, you might be able to use a noise filter to help cut down on the mud, but again there's NO miracle plug-in/filter for this.
Are absolutely ALL the wirelesses useless? I recently fixed a scene (by the fore mentioned studio) where I was given two speaking actors on screen and only one wireless mic (the other was not recorded!!) and was able to make the two actors audio match very well.