correcting audio

tdsilk wrote on 8/9/2005, 10:03 AM
Hello,

I recently recorded a event with two different camcorders (canon gl2 and sony vx2000). The vx2000 was directly linked to an audio feed which filtered crowd noise and the gl2 had a shotgun mic. The problem is matching the GL2's audio which sounds more like a theatre hall and the VX2000 which is very clean with no extra room noise. Is there a specific filter that will help me clean up the GL2's audio to match the vx2000's? Btw, I using Vegas 6b and not very good at using the audio filters.

Thanks,
Troy

Comments

bgc wrote on 8/9/2005, 10:12 AM
Unfortunately not. It's really hard to remove reverberation and room noise. It's actually easier to add it. Maybe try adding reverb to the dry signal and make it sound like the GL2?
tdsilk wrote on 8/9/2005, 10:33 AM
ok. that makes sense. Any tips for avoiding this in the future?
musicvid10 wrote on 8/9/2005, 5:17 PM
Actually, what you are trying to avoid is exactly what I use to create a natural sounding audio mix that replicates the warmth of the hall.

To explain: Camera A is tied to the stereo feed from the audio board. It is a completely dry mix, no processing and little audience noise since it is only the stage, actors', and pit mics, hopefully well mixed. Usually I feed the stage and body mics to the left channel and the orchestra to the right so I have SOME control over the overall balance in post. Eventually, of course, these get mixed to center channel (L=R). Ii'll generally give this track a modest 2:1 compression.

Camera B uses its onboard stereo mic, or ideally a pair of condensors spaced about 20 feet apart in the back row of the main floor of the auditorium. The sound captured on this camera is stereo, containing hall reflections and ambience, audience response (you can always dip out the coughs or guffaws), and just enough of the delayed direct audio to create a sense of depth, that elusive third dimension in live audio. When adding this track, ideally your cameras were synched, but if not, find "tap-in" and "tap-out" points (snare drum hits for me) at the beginning and end of each act, and use Vegas' time stretch to line them up exactly, then delay the whole track 10-20 ms depending on the length of your hall. (Take the distance from the proscenium to the mic in feet, and divide by 2.3 to get a trial delay time in ms.)

When setting the levels, add just enough ambience to bring the mix "alive," don't overdo it. No need to normalize the ambience track, it should mix in fine without.

Sorry if this is "too much information," these techniques were developed over time and with tweaking can deliver some really nice natural-sounding location audio.

P.S. I'd be happy to email you a short mp3 clip of my last production mixed this way if you're interested.