Eliminating background noise of people's voices

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fryroadrunner
Posts: 2
Joined: Thu Jan 17, 2008 7:58 pm

Eliminating background noise of people's voices

Post by fryroadrunner »

Is it possible to eliminate, or greatly reduce, people's voices in the background? I am totally new at editing sound. I have only performed the very basic functions and most subjects in the help manual are over my head! Besides, I can only find info referring to background hiss, etc. Also, I will be making more recordings in the same unfavorable setting, so are there any suggestions on setting up my Amadeous Pro recordings. I am recording on a MacBook, using the internal mic. (I do have an iMic if that would be any better.) Another person and I are conversing in a crowded, noisy store, recording directly in front of the MacBook. Handing an external mic back and forth would not be possible in this situation. Thank you for any suggestions. [/b]

CDJonah_alt
Posts: 379
Joined: Thu Mar 15, 2007 3:57 pm

Eliminating background noise of people's voices

Post by CDJonah_alt »

Any extraneous sound you don't record is sound you don't have to
remove. I would look at getting a directional mike, possibly cardiod or
hypercardiod. For the example you cite, I would try 2 cardiods, one
pointing towards each speaker. For example core sounds have some small
cardiods that might work (I have been happy with the omnis that they
sell -- never tried the cardiods).

Chuck

fryroadrunner wrote:
Is it possible to eliminate, or greatly reduce, people's voices in the background? I am totally new at editing sound. I have only performed the very basic functions and most subjects in the help manual are over my head! Besides, I can only find info referring to background hiss, etc. Also, I will be making more recordings in the same unfavorable setting, so are there any suggestions on setting up my Amadeous Pro recordings. I am recording on a MacBook, using the internal mic. (I do have an iMic if that would be any better.) Another person and I are conversing in a crowded, noisy store, recording directly in front of the MacBook. Handing an external mic back and forth would not be possible in this situation. Thank you for any suggestions. [/b]




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Charles D. Jonah CDJonah@anl.gov
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fryroadrunner
Posts: 2
Joined: Thu Jan 17, 2008 7:58 pm

Post by fryroadrunner »

Thank you, Mr. Jonah,

I will check out the directional mics. However, I looked on CoreSounds.com and they had no products to offer except recorded CD's. I'm sure I can track that information down. As someone else is needing the information, I still need to edit out that extraneous sound on my one recording. Can it be done with this software?

CDJonah_alt
Posts: 379
Joined: Thu Mar 15, 2007 3:57 pm

Eliminating background noise of people's voices

Post by CDJonah_alt »

http://www.core-sound.com/mics.html

fryroadrunner wrote:
Thank you, Mr. Jonah,

I will check out the directional mics. However, I looked on CoreSounds.com and they had no products to offer except recorded CD's. I'm sure I can track that information down. As someone else is needing the information, I still need to edit out that extraneous sound on my one recording. Can it be done with this software?




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Sonic Purity
Posts: 82
Joined: Sat Nov 10, 2007 11:58 pm
Location: Pasadena, California, U.S.A.

Re: Eliminating background noise of people's voices

Post by Sonic Purity »

fryroadrunner wrote:Is it possible to eliminate, or greatly reduce, people's voices in the background? I am totally new at editing sound. I have only performed the very basic functions and most subjects in the help manual are over my head! Besides, I can only find info referring to background hiss, etc.
(Adding to Chuck’s posts...)
This really needs to be done at the time of recording, with unidirectional microphones. Our human brains do a lot of “selective listening” that audio hardware and software is incapable of performing.
I am recording on a MacBook, using the internal mic. (I do have an iMic if that would be any better.)
The internal mic on nearly any computer, tape recorder, or similar is about the worst possible option: these were not meant for use in noisy environments, usually. Hopefully you know that the iMic is not a microphone, and is rather an analog-to-digital (and vice-versa) converter. I personally dislike iMics, especially for using with an external microphone for “mic level” work, yet apparently some folks do OK with them. (I am only familiar with the older iMics in the round gray case.)
As someone else is needing the information, I still need to edit out that extraneous sound on my one recording. Can it be done with this software?
I do not know of any software that will magically extract unwanted voices from a recording, for the simple reason that, to the software, it is all valid audio sound, and there is no basis to decide what sound is desired and what sound is not wanted. Best thing to do is make copies of the original, and experiment with different settings on the copies. Try things like filtering, compression, gating, and so forth. Experiment… if nothing else, you will learn a lot about these tools :P . Amadeus Pro should do about as well as anything else… the main thing would be the processing tools available.
))Sonic((

0db
Posts: 36
Joined: Thu Feb 01, 2007 11:26 pm
Location: San Francisco

Post by 0db »

fryroadrunner-

First thing, read everything that everyone else has said, 'cause it's all quite true.

The problem that you are inadvertently creating with your present recording method falls into the "signal to noise ratio" area of audio problems. Simply put, in all audio work you want to obtain the highest possible ratio between the sound that you want (signal) and any other sound that you don't want (noise).

Filters are not going to be a great help in your situation, because the "noise" that you want to eliminate has basically the same audio characteristics as the "signal" that you want to retain. Generally, filters are useful only when the undesired noise has some characteristic which allows it to be differentiated from the desired signal. For example, you mentioned filtering for hiss. That is possible because hiss generally is heavily weighted towards the higher audio frequencies, and it is possible to greatly reduce those frequencies and still have decent voice audio. Note, though, that this is a different situation if your desired audio is not voice, but high fidelity music, because the music will need to reproduce in the same frequency spectrum as the hiss, so there is another example of a difficult "signal to noise ratio" problem.

The suggestions regarding the directional microphones are probably your best bet, as that type of microphone, by it's design, tends to cancel sound from directions other than straight on. As the other folks have said, it's always best to make the best possible recording rather than trying to fix it later.

Another thing that was mentioned is also quite true, and I speak from personal experience: the only way to learn your way around all this stuff is to jump in, try everything that you can think of, and find out which things work and which don't. (I wonder what will happen if I try...)

NEVER do this on your original sound track; ALWAYS make a backup because things WILL go wrong. It may sound like overkill, but if you are not sure exactly what is going to happen at each step, I recommend that you make backup copies at each and every step of your process (you can always throw them away after you are finished, but if don't, and you screw up something, you may lose several steps in your processing.)

If your audio processing involves multiple steps, it also helps to keep notes as you go, of what you did and the sequence in which you did them. This is particularly useful if you anticipate having to do the same sort of processing on different files, over a period of time. (Let's see now, did I boost the high end by 3 db, or did I reduce the low end on that one?)

That's enough rambling for now, good luck and dive right in there. If you run into specific problems, or need some help, don't be afraid to ask... I know from personal experience that there are some very good people around here to help you.

0db

jimkirk
Posts: 2
Joined: Sun May 18, 2008 10:27 pm

This might help for recordings you already have...

Post by jimkirk »

If you have a stereo recording and the offending voices are mostly in one channel or the other (or both, but NOT centered), you might be able to clean things up a bit using a spatial filter. It's worth a try.

I've used Airy's Speedster (http://airy.andre.online.fr/AU/#speedster) when cleaning up mono LPs and 45s that I digitize using a stereo pickup, much better than simply combining the left and right into mono. I know this works with Amadeus II, I thought it worked with AP, but it doesn't seem to appear in my AU menu list when I just checked. (I recently upgraded to 1.3, maybe that has something to do with it.)

Anyway, besides pitch and tempo shifting, it can do a simple Left, Center, Right spatial filter.

In the main menu, set the L & R sliders to zero, set the volume around 1 (1.0027 is as close as I can get, it's a little funky.)

Click on the "TIME" button in the upper right corner of the window.

Select "Triphonia" and set all three shift sliders to zero (center position) for no pitch shifting.

Set the "L" and "R" volume sliders to zero, set the "C" slider to around one.

Set the Pan center slider to zero (center position). The left and right pans should have no effect since the volume settings are zero.

Check the results using the preview.

What this does is remove audio that's predominantly in the left or right channel, but passes audio that's spatially centered. Similarly, you can isolate audio that's spatially right or left. Play around.

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