Recording - June 2015 - 60

By Paul J. Stamler

Part 6: The Example Session-Mic Placement
At long last, we arrive at what I did on the day of the session with Ottoman
Underground. Before I start talking, you might want to listen to the clip again
(and if you haven't downloaded the clip, it's at http://is.gd/RECFirstStepsClip1).
Having talked for two articles about microphone theory, it's time to get down to
brass tacks.
Take a look at Figure 1, a rough outline of who was where in the studio. The
circles with a line attached represent microphones (it's a standard representation);
the line side represents the front of the mic. This is a bird's-eye view of the session;
you'll have to rely on my verbal descriptions to understand mic placement heights.
Oh, and left-to-right in the studio is equivalent to left-to-right in the clip.
Dana and her clarinet
For Dana, I chose a Neumann KM 84 small-diaphragm condenser mic.
Neumann hasn't, to my knowledge, published a full response curve for the KM 84;
Figure 2 is as close as they've come. The graph depicts a mic that's essentially flat
(on axis) between 40 Hz and 18 kHz, with a tolerance for deviations of ± 2dB
(those are the dashed lines). That's a tolerance big enough to drive a truck
through-deviations of 2 dB could result in a mic that is bright, or dull, or anything
in between. However, I relied on 30 years of experience with this microphone,
which told me that though this drawing is a "Louie In Marketing" curve (see Part 5,
May 2015), it actually describes the mic's performance fairly well. The KM 84 is
essentially flat on axis; more important, it stays that way off axis.

Why did that matter? The on-axis response
predicted that the KM 84 would give an honest
account of Dana's rich-sounding instrument; however, it was the off-axis response that clinched
my choice. You'll notice that Dana was fairly
close to Will in the studio, and I can tell you that
the tenor banjo Will plays is loud. I anticipated
that Will's banjo would bleed into Dana's mic,
and welcomed the leakage as a useful tool to
help create a sense of space in the recording; for
a much fuller discussion of this technique of "controlled leakage"-and its possible pitfalls-see
my article "Outwitting the Phase Monster, Part
1" (Recording, November 2014).
So I was looking forward to some useful leakage, but I didn't want that leakage to be colored
by a clarinet mic with less-than-flat off-axis
response. My experience with the KM 84 told me
that its off-axis response could deliver the flat leakage I wanted. In a preliminary check as the band
warmed up, I determined that Will's leakage into
Dana's mic was more than 10 dB below his level
in his own mic, which meant we wouldn't have
phase problems (again, see "Outwitting the
Phase Monster, Part 1").
I placed Dana's mic above her instrument,
pointing down at the body. Some wind players
I've met believe that their sound comes from the
bell of the instrument, but research by physicist
Arthur Benade of Case Western University
showed that most of the sound comes from the
highest open hole. (Benade's classic Horns,
Strings and Harmony is good-if sometimes baffling-reading for people who record woodwinds.) Since encountering Benade's work I've
miked clarinets, flutes and saxes from "over the
holes", with good results.
Will's voice and banjo
I approached recording Will's voice and
banjo with a bit of trepidation. I've mentioned
that his tenor banjo is loud, and I was afraid of
getting too much leakage into his vocal mic, with
attendant phase problems (once again see
"Outwitting the Phase Monster"-both parts,
Recording November and December 2014).
I chose a Microtech Gefell M930 for Will's
voice; see Figure 3 for its frequency response. As
you can see, the on-axis response follows the
curve toward which large diaphragm condenser
mics have converged over the years (see Part 5
again), with a smooth boost in the upper
midrange/low treble frequencies. That boost
added a sense of immediacy to Will's voice, as
well as sharpening the consonants of his words,
which improved their intelligibility.

RECORDING June 2015

http://www.is.gd/RECFirstStepsClip1

Recording - June 2015

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