HELP: Cleaning up a digital voice recording

[lodger]

Posted September 01, 2005 11:33 Reply With QuoteEdit or Delete Message
Please Help.


I recently conducted a telephone interview for an enterainment/community website, but on the recording, I cannot hear the other side of the conversation over a persistent buzzing. So I'm trying to either reduce the buzz or enhance the voice, because little of it is audible in its present condition.

I used a standard Radio Shack Telephone-> Line In adapter, and the line in function of an Iriver 120 audio device. The call was transatlantic, conferenced through New York. When I put the resultant mp3 on my hard drive, the whole thing shows up with almost no peaks or valleys.

What can I do to hear the voice better? What software can I use (if any), where can I get it, and what do I have to do with it?

Please Help.

 

[punkin]

Noise reduction is tough...if the noise is persistent/consitent throughout you may be able to improve the over all recording but noise removal/reduction if done lightly if the noise is really noticable, attempts at removing the noise will likely result in damage or degredation to the desireable signal.

I have used Bias SoundSoap and Adobe Audition's noise reduction plug-in with good results for removing slight background noises. If you're not interested in a hi-fidelity recording result, but rather just recovering some intelligible audio, these devices may work for you.

Hope this helps.

 

[LfO]

If you're lucky, the buzz may have few overtones, and you'll be able to use EQ to filter it out, then boost the remaining signal. I don't personally know of any software that wouldn't be expensive overkill. However, IF you have a hi-fi stereo system at home (specifically one with a nice EQ - the more sliders, the better), or know someone who does, you may be able to see if this works.

1)Record to CD or tape (whatever media the stereo system will play)
2)set all the sliders on the EQ to 0 (or at least the same level) and hit play

The reason you want a lot of sliders (you can skip this if you want):
The human hearing range is from about 20 to 20,000 Hz (= vibrations per second). We percieve any doubling in frequency to be roughly equivalent - for example, the difference between 100 Hz and 200 Hz will sound the same as the difference between 200 Hz and 400 Hz. I only say this to explain why the numbers on the sliders aren't spaced evenly.
The more sliders you have, the smaller the pieces of that frequency range you'll be able to manipulate at one time. As I said, we're HOPING the sound is very focused in terms of frequency - any real-world sound includes overtones, or frequencies at various points in the spectrum above the main tone. So, you won't be able to eliminate the buzz, but you MAY be able to reduce it enough to make it usable.

3) Starting at the left (lowest Hz value), one at a time, pull a slider all the way down (this will be to a negative number, or a negative infinity symbol), and see if the sound is any clearer. If not, put the slider back up. Hopefully, reducing one frequency will reduce the buzz enough to make the recording useable. If so, you'll just have to boost the gain (volume) to hear the other speaker.


Hope this helps.

 

[punkin]

It occurred to me just now that if you're considering the Bias product, send them an email and ask if they could demo the result for you. I did this before I made the purchase. They offered to clean a short snippit of audio for me which I supplied. You could do the same and determine if this will be worth your while.

Good luck.

 

[Blue Bear Sound]

What can I do to hear the voice better? What software can I use (if any), where can I get it, and what do I have to do with it?

Please Help.

Send it to a professional studio? (One that specializes in audio restoration.)

Just a thought!

 

[gordone]

Send it to the CSI folks! If they can get an audio "recording" off of a clay pot, they can clean up your interview!

Seriously, if the recording is important, you might want to find a local studio/service that does forensic audio/audio restoration. Good luck!