Friday, April 30, 2010

Re: [Avid-L2] OT: Audio Question

Ben,

You are looking for EQ not Pitch Shift. The idea is that hum, buzz or
room noise can be eased out of the signal so as not to be nuisance.

http://en.wikipedia.org/wiki/Roll-off

Enough math there to keep Wilson happy.

The steepness or slope of the roll off is part of the design and can be
variable. You may also find your roll off filter is some one else's high
pass filter.

http://en.wikipedia.org/wiki/High-pass_filter

Of course some one else's high pass filter might be an unsharp mask and
have no relationship to audio whatsoever.

DD

Benjamin Hershleder wrote:
>
>
>
>
> OK... who wants to help a dumb old guy?
> Yes, that'd be me.
>
> So... I'm looking for an English translation of the definition below,
> as well as a method to demonstrate it.
>
> "Roll-Off:
> A decrease in audio gain in relation to octaves.
> For every octave decrease in frequency there is a difference of -12dB
> in audio gain."
>
> I thought I had deciphered this and did the following:
>
> 1- Created 2 pieces of tone. One was 300Hz and the other was 600Hz,
> both at -20dB.
> 2- I put a Pitch Shift plug-in on the 600Hz clip and lowered it 1
> octave (verified the shift through comparison).
> 3- Based on the definition above, my hypothesis was that the altered
> clip would now play back at -32dB. It didn't. It played back at -20dB.
>
> Any takers?
>
> TIA,
>
> B
>
> Benjamin Hershleder
> http://ContactBen.com <http://ContactBen.com>
> http://Hershleder.com <http://Hershleder.com>
>
> Wear It In Post!
> Fun T-shirts, mousepads & more
> for Post Production Professionals
> http://www.WearItInPost.com <http://www.WearItInPost.com>
>
> [Non-text portions of this message have been removed]
>
>

--
David Dawkins
780-905-9121
dawk2@shaw.ca

[Non-text portions of this message have been removed]

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