Cleaning up Police Interview

[mrmicguy]

The local police have brought me an interview they have recorded. The interview took place in a jail cell and is not very intelligible (lots of room reflections & background noise etc).

This interview is required to be played back to a jury and needs to be cleaned up to make it easy for them to hear.

I have the interview in .wav format and I have soundforge.
I know to have a go at EQing, gateing and compressing

Any ideas on where else to go?

Is it worth asking for the dimensions of the room and working out resonant frequencies etc and attenuating them?

Any advice is welcomed.

[Fredrik]

There is a noice reduction plugin in soundforge that can give good results, it samples the noice and subtract it from the file. If the soundfile is stereo it can be rewarding to listen to left vs right channels.

[max cooper]

Check this out:

http://www.wesdooley.com/aea/forensicaudio.html

http://www.wesdooley.com/aea/FAREC.html

maybe it won't help, but at least it'll make interesting reading.

[dach]

Any ideas on where else to go?

Yes, send it to someone who does this kind of work. I can recommend people if needed.

Other than that, I can not tell you what to do without hearing anything first.

I know to have a go at EQing, gateing and compressing

If that's what you know, then try it... I will give a few pointers... Pay attention to how you get it in the box and explore the possibilities of what you can do BEFORE the audio hits the convertors...

Once ITB, there are many companies that make products developed specifically for forensic audio. I can recommend some if needed...

You can certainly do good things in Sound Forge and other programs that let you chain plugs provided you have the correct tools and know how to apply them... however I don't like SF's chainer...

Remember you are doing audio work for the LEGAL industry now... the rules change a little. Document everything you do carefully. Believe it or not, there are actually procedures one must follow in regards to working with evidence and the custody of said evidence. Your local cops may not be fully aware of them but when life, liberty or finances are at stake, you can bet there are people that look closely at everything.

What you do could have an enormous impact on multiple peoples lives, families, finances, etc.... perhaps even yours... Although it's usually not all doom and gloom, I advise you to tread carefully.

Good Luck... unless what to do with the audio is a "no brainer", I would advise you to at least consult with someone who has experience along these lines of things...

Chuck