--- In Kim Cascone <> wrote:
> also, while having dinner with a film sound guy in Paris he said
that
> most location recordists in the European film industry have
abandoned
> M-S for XY and A-B
> not only because of the decoding mess but because people
complained
> about the 'faux stereo effect'
One of the problems that film and television people have with MS is
the concept of mono-compatibility and how you interpret it...
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. 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. So this
is 'mono-compatible' in terms of not causing comb filtering when
summed to mono, but not in terms of retaining all of the information
that was present in the original stereo signal!
In comparison, a properly configured coincident or XY pair (e.g. Rode
NT4, AudioTechnica AT825 et al) will collapse to mono with no comb
filtering and without losing any of the signal. This is handy in post-
production and is also good when the signal is summed to mono during
playback. The mixing engineer can check what it sounds like in mono
and create a balance that works well in 5.1, stereo and mono.
If an AB pair is used, converting to mono in post-production is
simply a matter of using only one of the mic signals (unless they're
very widely spaced apart and/or very close to the sound source, the
two mics should sound pretty much identical with only time
differences between them). That's not going to be much help if the
stereo signal is being converted to mono during playback (in which
case you have to be careful of comb filtering when placing the mics),
but it does give the post-production people something useful to work
with.
But if you're not making recordings for film, television or
documentary use, perhaps mono-compatibility is a non-issue. My
personal POV is that we're living in 2008 and mono-compatibility
ought to be something relegated to the same bin as DATs and [insert
whatever technology you think is well past its 'use by' date]. But it
bit me on the bum as recently as 18 months ago...
- Greg Simmons
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