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horrible background buzzing noise

Posted: Sat Feb 01, 2014 8:42 pm
by Shevach
Hi there!
I don't know if this is the place or not but here goes.
Can someone tell me how I can get rid of this horrible buzzing sound that you hear on this recording.
I tried playing around with different settings on the noise removal but it just made things worse.
Thanks a lot
Sh P

Re: horrible background buzzing noise

Posted: Sat Feb 01, 2014 9:29 pm
by kozikowski
Noise Removal isn't the miracle drug that everyone wants it to be.

First recording? It sounds like you're trying to do an interview across the room from the microphone. Even the big kids can't do that.

Describe your microphone, computer, the room, etc.

Koz

Re: horrible background buzzing noise

Posted: Sat Feb 01, 2014 9:48 pm
by Shevach
Thanks for your fast reply.
I used a MacPro with the internal mic.
It was just a regular room and we sat about foot away from the mic.
Not such a good idea? But is there any hope to save it

Re: horrible background buzzing noise

Posted: Sun Feb 02, 2014 12:47 am
by Trebor
Shevach wrote:... is there any hope to save it
Lots of notch filters required to remove the buzz-hum :
copy and paste the code below into something called Nyquist Prompt which is in Audacity's Effect menu ...

Code: Select all

    (setf s (notch2 s 90 5))   
    (setf s (notch2 s 632 50))  
    (setf s (notch2 s 899 50)) 
    (setf s (notch2 s 2898 20))  
    (setf s (notch2 s 12192 50))  
    (setq mysound s)
    (setq q 25)         ; set the base Q for the filter
    (setq iter 44)     ; set the number of iterations
    (setq freq 216.545)  ; set base frequency

    ; start the DO loop
    (dotimes (i iter mysound)   
    (setf mysound (notch2 mysound (* freq (1+ i)) (* q (1+ i))))
    )                     ;end of loop
It will look like this ...
buzz removal code (only valid for ''Yonason'' audio sample).gif
buzz removal code (only valid for ''Yonason'' audio sample).gif (13.59 KiB) Viewed 2293 times
Select the section of audio with the buzz and apply Nyquist Prompt like an effect, and voilĂ  the buzz has gone ...
Yonason, before-after code shown applied.wav
(766.27 KiB) Downloaded 74 times
(the code only removes buzz, not hiss).

Re: horrible background buzzing noise

Posted: Sun Feb 02, 2014 12:50 am
by kozikowski
The picture is of my noise removal settings and the clip is post correction. Noise Removal works in two steps. The first step is to get a "profile" by drag-selecting a portion of the show with noise and no performance or other noises. The second pass is the actual reduction.

I uses the first second or two of your clip as profile.

Koz

Re: horrible background buzzing noise

Posted: Sun Feb 02, 2014 1:07 am
by kozikowski
I didn't know MacPros came with internal mics.

On the newer laptops, there is a setting in Apple > System Preferences > Hardware > Sound > Input > Internal Microphone: [X] Use Ambient Noise Reduction.

Try that on a test interview before you get in a car for that President Obama meeting. Typically, that only works for voices. That's not going to work if you record music.

Koz

Re: horrible background buzzing noise

Posted: Sun Feb 02, 2014 9:55 pm
by Shevach
Thanks a lot. It worked perfectly!!! (like magic)
I work with children (and teens) with learning difficulties so I like to record them in the beginning and then to record again a few months later to show them how much they improved.
In the old version (before the code you sent me) it was a little hard to hear now it's great. Thanks a lot
ShP
p.s You are right I don't have a MacPro but a MacBook!