Recording - July 2016 - 8

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Acoustic guitar recordings: blunt and boomy or rich and vibrant?
Here's a condensation of a recent email exchange between
Recording reader Tom Bowman (who's been in our Talkback column
before, and will be again, with interesting and highly relevant questions), and the ever-helpful Paul J. Stamler. We'll let Tom explain the
problem and touch on a few of the solutions Paul suggests.
I hear a lot of amateur recordings of acoustic guitar that sound
rather hard and blunt instead of rich and natural. Many sound
boomy, of course, because mics are too close to the body. But
there seems to be a space in between overly boomy and extremely
bright recordings where the recorded guitar lacks the rich
midrange and airiness of the actual instrument. I'm not talking
about high-frequency hash; rather, it's a bluntness and hardness
that seems objectionable. I hope I'm describing this adequately-
professional recordings rarely suffer from this unpleasant quality,
no matter whether the guitar is mostly high frequency strumming or
the featured instrument.
I know how sensitive acoustic guitars can be to microphone
placement and distance. I think I hear this quality more frequently
with small-diaphragm condensers than with large-diaphragm condensers (perhaps that's just my limited experience). I could never
get guitar recordings to sound natural with a pair of Shure SM81s,
and I'm trying to figure out how to proceed from here.
My nemesis with the SM81s was a sound that seemed to lack
nuance and life. The frequencies were all there, but the tracks
never seemed to have that appealing liveliness and character that
pro recordings have. They sounded almost like shouting, whereas
acoustic guitars, at their best, have a quality that draws you in
and opens up like a voice does. I want to get past lifeless, clunkysounding recordings so the musicality comes through better. Does
that make any sense?
My guitars are a Martin D-28 with vintage bracing, big and
sometimes boomy, and a Taylor 814c grand concert with rosewood
back and sides, very bright. Beyond the SM81s I have a Neumann
U-87ai, a modified Oktava MK-219, and a Blue Baby Bottle. I also
have a pair of Royer R-121 ribbons. My mic pres are a Peavey
VMP-2, AEA RPQ, A-Designs Pacifica, and a Rupert Neve Design
Portico 5032 (2 channels), and I run Pro Tools with an Avid Omni
interface.
I followed your First Steps advice and worked with an engineer
at GIK Acoustics to treat my spare bedroom studio. The dimensions
are terrible (roughly 11 X 12 X 8.7) but with a cloud, corner traps,
and bass traps on the walls the room sounds good-not big, but
professionally treated. I monitor through Truth Audio monitors with
a Hafler amp.
So my question is this: What are the primary causes of this unpleasant lack of tone... or, better yet, what are the best ways to avoid it?
Simply reducing a cardioid mic's proximity effect by moving the
mic farther from the guitar (and aiming away from the body and
sound hole)? Changing to an LDC? Switching to an omni mic to
avoid proximity effect altogether, while capturing more resonance
and reflections? (I use a little Sony PCM-D50 digital recorder as a

songwriting sketchpad. It has a pair of omni SDCs built
in in an XY configuration. I am always impressed by the
natural and open quality of the recordings it makes.)
Obviously, engineers make great recordings with
SDCs, so the type of mic can't be the problem. Any
input would be very helpful. Best,
Tom Bowman

Hi Tom: If the acoustics of the recording room are
decent (and it sounds like they're better than just
decent!), you should be able to get good recordings
with an SM81, by placing it about a foot from the guitar, over the 14th fret, pointing at the neck-or, if you
don't get enough bass, angled slightly toward the
soundhole. The guitar shouldn't have brand-new
strings; I find that changing strings one or two days
before a recording session gets the best results, and
keeping the guitar well-humidified helps a lot too.
(Guitar stores sell a variety of humidifiers.) Even pick
material can affect tone; try a thicker Delrin pick for a
more mellow sound, a thinner pick will be brighter.
After the guitar itself is sounding its best in a good
room, get the electronics right. The SM81 is probably
not the limiting factor; that's the mic I recommend to
people starting out recording guitars; properly used, it
provides remarkably good sound for the money.
For other readers' reference, I'll note that "thin, hard
and bright" usually makes me suspect a cheap preamp
and/or audio interface. Once that hard sound is in a
recording, no EQ or other treatment will get it out. Your
preamps won't have that issue.
You might want to stick with the U87ai for recording
your guitar; U87s and D-28s make a really nice synergy. Again, I'd point it at the 14th fret from about 10"
or a foot away; on the U87 I'd use the bass rolloff as
needed to keep it from getting boomy.
For stereo you might give the SM81s a try as a
crossed XY pair, on about the 16th fret from the same
10-12" distance, running them into the Peavey preamp to help take the edge off. (In my experience the
Peavey sounds best using the unbalanced outputs, not
the balanced ones.) Again you'll probably need the
bass rolloff on the SM81s, probably the gentle one
rather than the sharp one.
Oh, one trick that I've found makes the SM81s
sound better is this: at the beginning of the session,
exercise both the pad switch and the bass rolloff switch
by turning them back and forth 3-4 times. Then
unscrew the capsule about halfway and screw it back
in again. All those maneuvers scrape oxide off the various contacts, which can rectify the signal and make it
harsh. Peace-PJS

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RECORDING JULY 2016

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