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Audio Analysis

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(@holymans)
Posts: 2
New Member
Topic starter
 

Hello all,

I am new to this site and I am new to forensics. I would like to ask if any of you out there, know about forensics audio analysis software for either Mac (including UNIX) or Windows? I would also be very grateful for any hints or resources that I could use to enhance my understanding of forensic analysis of audio.

Thank you very much,

Adam

 
Posted : 25/12/2005 12:19 pm
nickfx
(@nickfx)
Posts: 131
Estimable Member
 

Hi

I use DC Live Forensic 6 (http//www.enhancedaudio.com/dc_live.htm), the interface is confusing as h*ll but is has quite a number of 'easy to use' tools but you do still need to understand audio to a fairly advanced degree.

You can also filter incoming feed live whilst recording the filtered and unfiltered sound, quite cool.

Once you know what you are doing you can achieve some pretty amazing results, its cool to be given a tape of essentially white noise and hand back a the full conversation that took place.

Any other Q's dont hesitate to get in touch.

Nick

 
Posted : 27/12/2005 1:49 pm
(@holymans)
Posts: 2
New Member
Topic starter
 

Nick,

thank you kindly for your feedback. I have heard about DC live Forensic from a friend some time ago, but never had a chance to take a look at it more carefully. Now I will take it for a spin for sure. Thanks!
I am not very knowledgeable about audio editing/altering. Could you recommend me some resouces that would be helpful in understanding the processes?

In short, I have been contacted by a friend who has some old spool recordings (from 60s) of 1 on 1 interviews, that she would like to have on a CD. Since I work for the A/V industry that did not seem a problem, but after listening to a few of them, I noticed that on almost all of them, there is a clicking noise that probably is coming from the recorder itself. I would like to be able to figure out on what frequency the human voice is normally and cut out the rest inluding that noise.

I thought of asking you folks as you probably have a lot more expertise in this area. I am a Mac addict and would love to be able to do this on a Mac, but PC will do too.
After watching some CSI series on TV, I have come to believe that there is a software that can allow you to extract voice from fairly noisy recordings. However I also realise that this could be a fabrication just for a TV show.

Much appreciated,

Adam

 
Posted : 28/12/2005 1:47 pm
nickfx
(@nickfx)
Posts: 131
Estimable Member
 

DC Live will eat that for breakfast Adam, you can isolate the frequencies that you want to reduce and essentially 'delete' them from the stream. DC Live has a number of tools for the improvement of voice sourrounded by white noise.

You can download a demo which you could try out with the recording. I think you cant export, cant remember.

As for resources, the help files with DC Live are very good but I will take a look around for you.

Unlike computer forensics which they stuff up completely on CSI, the sound stuff is about right, removing traffic noise from a comversation and things like that is all possible.

Nick

 
Posted : 28/12/2005 4:18 pm
(@jtobias)
Posts: 4
New Member
 

Hi I use DC Live Forensics 6 and Adobe Audition. DC Live has a quirky interface but loads of useful features and should certainly be able to assist you to remove the clicking and popping that you are experiencing. Likewise Audition has inbuilt filters that can help you to achieve the same thing. If all you are trying to achieve is the removal of "noise" then you might want to stick to Audition which is cheaper, easier to familiarise yourself with initially and also as far as I am aware the 30 day evaluation version has no limitations at all!!

 
Posted : 30/12/2005 1:06 am
nickfx
(@nickfx)
Posts: 131
Estimable Member
 

Hi Joel, Adobe is a good idea hadn't thought of that.

Slightly off topic but have you tried Audacity? Its a superb sound editing program and free!! You can install all the normal plugins and the current beta version is fantastic. - http//audacity.sourceforge.net/. I'm struggling to find why its worth spending the money on Soundforge or the like.

In fact Adam you might want to give it a try as the noise removal tool is pretty good. Sorry I didnt mention it before.

Nick

 
Posted : 31/12/2005 2:56 pm
(@armresl)
Posts: 1011
Noble Member
 

Dc Live is only good if you have learned the interface. Adobe Audition is more for audiophiles and leaves a lot out. The spectral features are way below the norm. You can take the class on DC Live and you will probably enjoy it greatly. www.tracertek.com will get you started.

The best audio forensic programs come from Russia.

Remember that the software is just a small part of the overall equation. Get a good set of headphones like AKG studios, a Nakamichi Dragon would work nicely with those headphones LOL, external sound card as to not reintroduce interferance from hard drives, heatsink, fans, power supply, etc.

Hope all that helps.

 
Posted : 31/12/2005 10:33 pm
(@jtobias)
Posts: 4
New Member
 

Audacity - I'll give it a go.
Thanks

 
Posted : 02/01/2006 2:50 am
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