Klarinet Archive - Posting 000999.txt from 2001/01

From: "Benjamin Maas" <benmaas@-----.com>
Subj: RE: [kl] recording
Date: Wed, 31 Jan 2001 12:59:33 -0500

> -----Original Message-----
> From: rgarrett@-----.edu]
>
> At 10:43 PM 01/30/2001 -0800, you wrote:
> >Unless you (or your engineer) is experiences with doing multi-microphone
> >recordings, I'd stick to a stereo pair only. When you start introducing
> >multiple microphones into a session, you run the risk of *many* problems.
> >These can range from basic sound problems to imaging problems to phasing
> >issues (the worst problems to have). If you stick to a stereo
> pair in front
> >of you, you'll have a much better chance of getting a good recording.
>
> Ben,
>
> I was hoping you would respond.
>
> Could you explain the imaging problems and phasing problems you mention
> above? In other words, how do you set multiple microphones to
> avoid these
> issues?
>
> Thanks for a great post.
>

This is going to be exceedingly difficult to cover in an e-mail post as it
is a subject that entire books are written on. To try to cover it (without
writing a dissertation), it comes down to this:

1. Imaging-- The most natural sound will be from a stereo pair out in
front. However, acoustics don't always let us get away with this. The
piano may sound distant and undefined, the woodwind section in an orchestra
may get lost.... Thus, sometimes a spot mic is needed. However, whenever
you start adding mics, you are manufacturing an image. You have to consider
your sonic "picture" from left to right, but also front to back. With most
people's setups, (mixing in the analog domain), you'll realize that the
sound gets to your spot microphones before it gets to your front [reference]
microphones. There went your front to back imaging... There are also
issues as to how you go about panning your microphones. Do you pan hard
(left, right, center--LCR) or do partial pannings... Depends upon the
ensemble. You will usually get better mono-compatibility (phasing-- to be
discussed in #2) with LCR, but not always a realistic picture. This is what
"mixing" is about. You need to balance out these issues. When I mix live
music, I put things according to WYSIWYG (what you see is what you get).
Works 9 times out of 10.

2. Phase-- This is the big one... When recordings are out of phase, if
you do a mono sum, things will start to disappear. How do things get out of
phase? Assuming that all of your signal path is wired correctly, leakage
and bad image placement. When you have multiple microphones out you will
have other sounds bleed into your spots. When the sound is entering more
than one microphone at the same time, you open the door for phasing issues.
It can happen with cardiod mics, but even more often with omnis, or
figure-8s (as they are picking up from behind the microphone). In a
reverberant room (as much classical music is played in), the leakage thing
becomes more of an issue. In a studio, sometimes you put up movable walls
called gobos, to help isolate sounds.

Now, phasing isn't always bad. Classical music is built on hearing sounds
blend. When they don't blend (if you have too much isolation or if you are
in a really dead room), the music doesn't sound as good. So in a recording,
you need to make sure that everything is always there, but there aren't too
many individual sounds.

--Ben

Benjamin Maas
Freelance Clarinetist and Recording Engineer
Los Angeles, CA
benmaas@-----.com
http://www.fifthcircle.com

---------------------------------------------------------------------
Unsubscribe from Klarinet, e-mail: klarinet-unsubscribe@-----.org
Subscribe to the Digest: klarinet-digest-subscribe@-----.org
Additional commands: klarinet-help@-----.org
Other problems: klarinet-owner@-----.org

   
     Copyright © Woodwind.Org, Inc. All Rights Reserved    Privacy Policy    Contact charette@woodwind.org