207d
instruction Manual
Aphex Systems Ltd. Model 207D
Page 16
207d
2-ch tube mic preamp with adc
Page 17
Aphex Systems Ltd. Model 207D
tronic matrix circuit processes both microphones and
provides Left and Right channel outputs. This method
vectorially extracts the left and right channels from
the sum and difference signals (the middle cardioid
and side figure 8 patterns).
Generally, M-S is practiced with specially built micro-
phones that are sold with the M-S processor. The mic
preamps are normally integral to the processor. How-
ever, certain M-S processors allow you to use external
mic preamplifiers so you could introduce a Model
207D. When doing so, just be sure to set the gains of
the two channels reasonably close and do not change
them during the recording. With M-S recording, the
stereo separation will change if either the middle or
side gain should be changed.
BINAURAL TECHNIQUE
This attempts to record sound like the ears hear it
using two closely spaced microphones either worn
on a person’s head near the ears, or located inside
of a dummy head with simulated ear canals. It
attempts to capture sound waves with the refractions
that occur naturally due to the shape of the head.
These days, binaural microphones are commercially
available that come with a matched dummy head.
However, many incredible recordings have been
made with two small identical omnidirectional mics
mounted to eyeglass frames.
For those recordists that do much of their work in
binaural, the Model 207D is perfect. Its low noise
and clear open sonic quality generate recordings that
are incredibly realistic and beautiful, catching all the
nuances and details.
FURTHER READING
There are more microphone techniques than we can
cover in this manual. Many reference books exist that
go into great detail. Here are a few: “Modern Record-
ing Techniques” by Huber and Runstein, “Sound
Reinforcement Handbook” by Gary Davis and Ralph
Jones, and “Introduction To Professional Recording
Techniques” by Bruce Bartlett. If you are one who
enjoys the challenge of recording, we believe you
will truly appreciate the outstanding performance
benefits afforded by the Model 207D.
their work. The low noise and highly detailed, open
sound of the 207D delivers breathtaking results. All
expert recordists know the techniques we’re about to
show you. However, others may find them interesting
to learn about.
SPACED-PAIR TECHNIQUE
About the most obvious technique is using two
microphones spaced apart some distance and
pointed directly at the sound source. The spacing
between mics and distance from the source depends
on the width of the sound platform you want to
include.
With spaced-pairs there will be a phase difference
between the two mic outputs. This can cause can-
cellation of certain frequencies. An accepted com-
promise is called the 3:1 Principle. According to this
principle, you should place the microphones 3 times
as far apart as their distance to the front of the sound
source. With such a wide separation of the mics,
omnidirectional types are called for. Otherwise you
might exclude the whole center of the sound stage
from adequate coverage.
X-Y TECHNIQUE
Also called a “COINCIDENTAL PAIR”, this technique
employs two cardioid pattern microphones. The
grills of each microphone should be placed as close
together as possible without touching. Each micro-
phone should be positioned at right angles to each
other. Use the intersection of this 90’ angle as a sight,
and aim toward the middle of the sound source (see
illustration on subsequent page). The microphones
should be of the same make and model.
An advantage of this technique is better rejection of
back-side room noises that include the audience and
slap-back or echo. The X-Y technique is often used to
record noisy live events.
M-S TECHNIQUE
Another popular stereo micing technique is referred
to as the “Middle-Side” technique. This method
combines two microphones of different response
patterns positioned along the same horizontal plane.
One is a cardioid mic which is aimed directly at the
front-center of the orchestra. The second microphone
has a figure-eight pattern positioned so that the axis
of the lobes are lateral, facing left and right. An elec-
Using the 207D