Editing Audio for Local Police Interegation -Sound Forge - PC

Subject:Editing Audio for Local Police Interegation Posted by: Curtsong Date:1/28/2004 11:37:13 PM I'm trying to help company make a confession tape in an interegation more audible. I seem to clean up most of the noise, and low rumble in the conversation, but, I still can't get the accusee's audio to the point of understandable. It doesn't help that he speaks softly and with an accent too. This is an audio from a video. I only have the audio and am not seeing the video. Has anyone had any experience in this area that can throw me some suggestions? Greatly appreciate it. Curtsong curtsong@comcast.net
Subject:RE: Editing Audio for Local Police Interegation Reply by: metrazol Date:1/29/2004 11:01:36 AM Uhm, well... Here's a bit of a problem. You planning on using this in court? I hope not, since the chain of evidence is, well, complex when it comes to any digital file. Apparently your generic sound engineer can make suspects say entirely new statements and remove sounds of phone books being swung automagically with no detectable artifacts or glitches, or at least we can if you believe defense attorneys... Now for getting the sound of the interrogation. First off, lean on the Noise Reduction plug-in. It's really, really good. Takes a bit of reading to use properly, but the docs are quite good. Next, EQ out anything outside of the range of human speech plus or minus a few Khz. A nice filter can also bring mids to the forefront. Then use good ol' normalization when you think you've squashed most of the noise to even out the levels. No guarantee any of this will work, but it's what I do when cleaning up recordings...though no confessions so far... ;-) Oh, and if you're looking to transcribe, try a speech recognizer. They work on a bunch of odd points in phonemes that sometimes stand out behind noise. There are a few good ones that might get you a usable transcript or at least fragments that you can use to pinpoint spots where you might need to boost certain phonemes. Heck, even just a chart of what phoneme is at what frequency range can be helpful when EQ'ing to increase audability. P.S. Yes, I work with TTS and recognizers all the time, I know, I'm a geek.
Subject:RE: Editing Audio for Local Police Interegation Reply by: Curtsong Date:1/29/2004 12:41:57 PM Hey Thank you so much. These are all helpful suggestions. I've already made a considerable difference by starting with the noise reduction then moving on to eqing. And I wasn't using the noise reduction properly either. I've found my iZotope Ozone is coming in very handy too with it's spectragraph and multiband's as well. I'm not too familiar with TTS or recognizers. That's interesting. What would you recommend?

Subject:Editing Audio for Local Police Interegation

Posted by: Curtsong

Date:1/28/2004 11:37:13 PM

I'm trying to help company make a confession tape in an interegation more audible. I seem to clean up most of the noise, and low rumble in the conversation, but, I still can't get the accusee's audio to the point of understandable. It doesn't help that he speaks softly and with an accent too. This is an audio from a video. I only have the audio and am not seeing the video. Has anyone had any experience in this area that can throw me some suggestions? Greatly appreciate it.

Curtsong
curtsong@comcast.net

Subject:RE: Editing Audio for Local Police Interegation

Reply by: metrazol

Date:1/29/2004 11:01:36 AM

Uhm, well...

Here's a bit of a problem. You planning on using this in court? I hope not, since the chain of evidence is, well, complex when it comes to any digital file. Apparently your generic sound engineer can make suspects say entirely new statements and remove sounds of phone books being swung automagically with no detectable artifacts or glitches, or at least we can if you believe defense attorneys...

Now for getting the sound of the interrogation. First off, lean on the Noise Reduction plug-in. It's really, really good. Takes a bit of reading to use properly, but the docs are quite good. Next, EQ out anything outside of the range of human speech plus or minus a few Khz. A nice filter can also bring mids to the forefront. Then use good ol' normalization when you think you've squashed most of the noise to even out the levels. No guarantee any of this will work, but it's what I do when cleaning up recordings...though no confessions so far... ;-)

Oh, and if you're looking to transcribe, try a speech recognizer. They work on a bunch of odd points in phonemes that sometimes stand out behind noise. There are a few good ones that might get you a usable transcript or at least fragments that you can use to pinpoint spots where you might need to boost certain phonemes. Heck, even just a chart of what phoneme is at what frequency range can be helpful when EQ'ing to increase audability.

P.S. Yes, I work with TTS and recognizers all the time, I know, I'm a geek.

Subject:RE: Editing Audio for Local Police Interegation

Reply by: Curtsong

Date:1/29/2004 12:41:57 PM

Hey Thank you so much. These are all helpful suggestions. I've already made a considerable difference by starting with the noise reduction then moving on to eqing. And I wasn't using the noise reduction properly either. I've found my iZotope Ozone is coming in very handy too with it's spectragraph and multiband's as well.

I'm not too familiar with TTS or recognizers. That's interesting. What would you recommend?