Software to reduce noise from an overdriven mic?

bino · #1 05-12-2006, 09:13 PM

I'm working on a wedding video project for a friend and I've discovered that 2 of the songs that were sung at the wedding were too loud for the camera mic (I didn't have time to adjust the gain) and the end result is some pretty nasty overdriving in spots. Is there any software or techniques available to reduce the sound of the overdriven mic? Any advice would be greatly appreciated. I know there are lots of people around here that know lots more about this kind of stuff than I do. Thanks again!

tbondo · #2 05-13-2006, 04:27 AM

Adobe Audition 2.0 (use to be CoolEdit) has some post-recording capability to get stuff out, but I'm not the guy to help engineer this recovery (I'm a rank amateur on the application)....DickensDad knows way more that I do.....and I'd guess that most recording suites (ProTools, etc) would have similar capability

bino · #3 05-13-2006, 07:55 AM

Hmm... ok. So nothing I could do without buying these apps then? Crummy deal. I'd use Audition or ProTools if: 1. I had them 2. I knew how.

Bob Womack · #4 05-13-2006, 10:05 AM

I'm very sorry to report that there is very little you can do to remove overmodulation (distortion) from a recorded signal. A big percentage of my work as an audio post-production design engineer is to "fix" audio from the field. I have some of the best tools anyone could have, both automated and manually-operated. We can clear up all kinds of audio anomalies including the sounds of generators, hum and hiss. However, when we are handed distorted material and asked to remove the distortion, we find ourselves up against one of the worst problems we face, and there is little we can do to make it any better that doesn't involved heavy compromises. This is especially true if the distortion is digital distortion, where all kinds of unrelated noise is generated.

However, if the distortion is typical analog preamp distortion, here is a hint, though it is a little distructive: When the electronics of a recording system are overdriven, the gain system is max'd out and squares-off the envelope of whatever waves were put through it at the point where the system was unable to reproduce any higher signal amplitude. The result is very much like the sound you get when you put an electric guitar through a fuzz box. Square waves generate lots of non-harmonic overtones, and that's what gives them their raspy sound. What do you do when you are trying to mellow out a fuzzed-up guitar? You roll off the high end to try to tame those non-harmonic overtones. You can try the same on your songs, if the loss of high end isn't too intrusive.

Good luck!

Bob

deltoid · #5 05-13-2006, 10:08 AM

It will be difficult if not impossible to remove anomalies from an overdriven mic (or preamp).... even with the most expesive software processing tools. What software are you currently using to edit the sound file? You can use something like Goldwave to lower the sound level of the waveform. You can also use it to compress the sound. This may help a little. Get the fully functional trial version here >> http://www.goldwave.com/release.php

There are also several plugins available (some free trials) that do an excellent job of noise removal if you current software supports VST, or other plugin formats. These are mostly only useful for removing background noise and hiss though. But "pop" and "static" removal may smooth out your recording somewhat, in certain spots.

http://www.algorithmix.com/en/denoiser_pro.htm

bino · #6 05-13-2006, 05:35 PM

Thanks everyone for the input, although it looks like there isn't too much I can do... I'll try Bob's suggestion and see how that goes. As far as software I'm currently using, I don't have much by way of audio, considering I've been focusing mostly on the video end of it. I'm using a mac, playing with some pretty basic stuff (iMovie, Garage Band, Sound Studio, etc.). I'll give it a go and see how I make out. Thanks again!

Highway_61 · #7 05-13-2006, 06:19 PM

Audacity is free and cross-platform. Audacity for Mac
You'll need to download Lame, as well, if you want to export as mp3.

I'm a Mac guy, but I got used to Audacity and now I can't "get into" GarageBand."

bino · #8 05-14-2006, 10:15 AM

Quote:

Originally Posted by Highway_61

Audacity is free and cross-platform. Audacity for Mac
You'll need to download Lame, as well, if you want to export as mp3.

I'm a Mac guy, but I got used to Audacity and now I can't "get into" GarageBand."

I'll check audacity out. I have it installed, but I've never really looked at it much. For simple audio editing and adding a little reverb/delay from time to time I've been using Sound Studio.