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Re: Re: Noise Cancelling (was Pollution)

Subject: Re: Re: Noise Cancelling (was Pollution)
From: Marty Michener <>
Date: Mon, 11 Feb 2002 11:14:54 -0500
Lang:

Intriguing!    If you recorded the two mics separately, as Left and Right 
channels, instead of hard-wired, you could still achieve the effect 
post-field by combining the sound channels in the editor, later, at 
adjustable phase and levels.  Or, retrieve the original at-focus sound and 
use that alone, if certain effects were later deemed undesirable.  Keep it up!

Marty

At 10:56 AM 2/11/02 -0500, Lang wrote:
>I just did a second test in which I tried to greatly reduce or eliminate
>"white noise" coming from behind the parabola (from a point source speaker).
>I immediately realized that I get a much better result if the second,
>polarity reversed mike is placed somewhere on the "inside" of the reflector,
>so that it is receiving the same sound level (from the white noise) as the
>main mike. I got good results by scrunching the head the the second mike
>down to the bottom of the parabola, along the axis, well below the focal
>point (= at the bottom of the dish).
>
>I also tested this arrangement using the on-axis playback of my bird song
>and found the same 7db reduction in signal level when using the noise
>cancelling mike.
>
>Encouraging! If this kind of setup allows for, let's conjecture, a 15-20 db
>reduction in background hiss due to wind or stream noise as well as a nearly
>complete elimination of distant rumble, while only reducing the on-axis bird
>sound (or other animal sound) around 7 db, then this has definite
>application, at least for parabolic-type recording.
>
>Lang




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