[Richard Crowley]

Im_Beta_00 wrote:
David Nebenzahl wrote:
On 10/10/2009 2:33 PM Im_Beta_00 spake thus:

snip

Since you're using 2 completely unsyncrhonized recorders, there's no
way in hell you're ever going to get that second recorder's sound to
cancel ambient noise picked up by the first recorder.

It wouldn't matter if you were recording on the SAME multi track
recorder. The laws of acoustics and physics deny any known solution
at this time.

Firstly, whenever you are dealing with a recorder that has no time
codes, and I assume that none of the recorders listed have time
codes, you are going to find yourself doing some "hand-synchronizing"
in post. I am not so nuts that I would even *think* of mixing any
of this stuff live. I need an ambient background that serves as a
"reference" level against which to mix the foreground.

Secondly, this is an area roughly 3 acres in area. Just about every
direction from the shooting site is thick with trees (good for
damping out the really obnoxious stuff) except for that 80 foot
driveway that comes from the sporadically trafficked street road,
where we expect the noise to be coming from. That short little road
is where the noise-cancelling recorder is going to be. The cast is
much farther away from the road.

The ambient noise of the wind, whatever it is, is going to be that
much worse, and potentially unsolvable, as we are going to be more or
less at the top of a mountain, even with windscreens on *all* of the
mikes. It's not like we are looking to record the sound of a
proverbial pin dropping on the floor. (And we are going to be mixing
in some light background music to prevent people from hearing the pin
dropping on the floor, anyways.) So, what we are actually concerned
with, is the dialog of the cast, minus the occasional car (50 or 60
feet away from the cast, maybe even 80 feet away) zooming by.

Well, some of this depends on how "loud" the noise is. We won't be
able
to cancel all of it, but some of it is bound to be useful.

Think about it a second
or three and I'm sure you'll agree. Being even a millisecond or so
within synch isn't close enough.

If I am within a millisecond, I am going to be doing a whole lot
better than if I were doing it a quarter second off.

It doesn't matter if you are time locked absolutely perfect to a
femtosecond. That isn't the issue. The issue is that the sound at
any two different points is guaranteed to be different, NOT JUST
IN TIME, and therefore cannot be cancelled by simple subtraction.
You are tilting at windmills. Once you have tried it and done a bit
more serious study of the underlying issues, you will realize that you
are playing a fools game.

I expect to
reduce the street noise to a manageable sound level, maybe one fourth
the sound level of the cast. That means that not all of the noise can
be subtracted out, but some of it ought to be subtractable.

Inpossible. You will never get there. People with budgets 10000000
times more than you have been unable to do this. And not for lack
of ideas or motivation. Actors who get paid millions and millions
of dollars for a single film still spend tedious hours and hours shut
up in ADR studios reproducing and re-recording their dialog in a
quiet studio environment. If there were some way of eliminating
this, do you REALLY think that someone wouldn't have discovered
this method by now?

Sorry to rain on your parade, but there are much more profitable
things that you could be spending your time and resources on.