[IRCA] Audio Phasing?

[Rob Moore <rmoore5@xxxxxxxxxxxxx>]

Date: Fri, 21 Dec 2007 12:41:08 -0800 (PST)
From: satya@xxxxxxxxxxxx
Subject: [IRCA] The Sony SRF-59: now with Audio Phasing(!)
To: irca@xxxxxxxxxxxxxxxx
Cc: jkenny809@xxxxxxx
Message-ID: <2921.64.95.191.233.1198269668.squirrel@xxxxxxxxxxxx>
Content-Type: text/plain;charset=iso-8859-1

Satya,

It sounds like what you are doing is the same thing as is done with the phasers available from Quantum, MFJ or other places, except that you require two radios to get the effect because you do it at the audio level, where the phasers out there generally do it at the antenna level and don't require two radios.  Admittedly, the radios are inexpensive but have you tried a phaser and is your effect any different or more pronounced?

Rob

Hi all:

I recently purchased my second SRF-59, and it got me thinking about
experiments I did as a teen in the 1970's with stereo audio sources, and
how canceling the signal that is common to both channels (usually drums,
lead vocals, etc.) left only those elements that were "stereo-ized" such
as rhythm guitar, etc.  David Hafler was also doing this in the 1970's,
only he became somewhat famous for it with his surround sound circuit (see
for example http://sound.westhost.com/project18.htm) ? too bad I didn?t
have a patent attorney back then?

At any rate, the effect is essentially audio phasing, and is accomplished
by joining the negative leads of the two stereo sources (usually L and R
speakers outputs from a receiver) together without connecting this union
to the speaker.  The two positive leads are then connected to either
terminal of a single speaker (or two speakers in series).  Electrically,
the common voltage portions cancel each other out (i.e., the vocals have
the same voltage at either terminal of the speaker's voice coil, and it is
a draw, so the vocals disappear) and all you have is the audio that is NOT
common to the two (the tambourine, etc. is all you hear).  It makes for a
neat surround-sound effect.  As long as the common element (voice, etc.)
is EXACTLY the same in both channels (same frequency equalization, dynamic
range, etc.), it works like a champ.

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