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7. Re: Decca Tree?

Subject: 7. Re: Decca Tree?
From: "John Lundsten" lundsten_john
Date: Mon Sep 1, 2008 3:38 am ((PDT))
Greg Simmons

When an MS recording is collapsed to mono (as still happens on some
television playback, for example), the side information is removed
from the sound altogether.

JL} Yes true, in mono difference information will be removed from any stere=
o
recording using any mic (or studio) technique, it is the nature of mono it=

has no width! In the case of MS what you end up with is solely the M mic
pointing at the subject IE what one would do if making a mono recording.  I=
n
the case of XY the mono will be a sum of 2 mics that inevitably are not
truly coincident, so there will inevitably be some cancellation in practice=

this may well not be a big problem unless the main sound source is in the
centre of the soundstage ( 2 mics summed not pointing at the subject will
sound inferior to 1 on axis mic).
A spaced pair recording will suffer considerably more phase cancellation, I=
E
the Mono & stereo result will be distinctly different from one another.

So if you had an MS recording made in a
forest with a narrator close up in the centre and forest ambience in
the sides, when collapsed to mono the forest ambience disappears
altogether, totally changing the sound heard by the listener.

This is just plain wrong, you would have to create a very odd recording wit=
h
the forest ambience in anti-phase for this to happen.
John L



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