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Moving The Mike
Adventures In Microphone Placement and It’s Subtle Rewards
EQ is the Devil. I’m talking pitchfork, pointy tail, little horns, cloven
hooves, the whole ensemble. Oh, I know there are a hundred “high end” EQ
processors out there and a few million users of them that might initially
disagree with that statement, but ultimately, equalization is a destructive
process that introduces subtle harmonic shifts into your signal that degrade
it each time it is utilized. Yes it’s an audio evil, but a necessary one.
You can barely get through even the simplest session without reaching for
some knob or another to twist. Whether it be to scoop out the mud at 350Hz,
introduce some “bite” at 2.3 kHz or adding some “air” up at 13kHz, it
invariably happens that some subtle tweaks are in order. The evil lies in
relying on EQ instead of your ears. You might be thinking “I rely on my ears
when I EQ”, but I’m saying that if you really listen as you set up the
mikes, you’ll need to do less to the signal after the fact. Which means less
signal degradation, and hopefully, higher fidelity…and all you have to do is
move the mike.
Take drums, for example. If EQ is Beelzebub, this the fiery pit it thrives
in. A typical drum setup includes miking the bass drum, snare, overheads
(for cymbals & the like) and possibly the toms, as well as some distant mike
placement to capture the sound of room. Any time you have more than one mic
in the same general area, you run the risk of introducing “phase
cancellation”. That is what happens when sound arrives at two microphones at
ever so slightly different times. We’re talking milliseconds here. Try to
picture a sound’s waveform: There are peaks in it that cycle up (positive)
and then down (negative). If you were to overlay a duplicate waveform over
it, but moved it slightly so that the ‘up’ peak were lined up with the
other’s ’down’ peak, you’d have a signal that is out of phase. In the worst
cases, they cancel each other out, based on simple middle school math: (+1)
+ (-1) = 0. In most instances however, there are just certain frequencies
within the signal that are being canceled, often resulting in a muddy snare
sound or a weird grinding in the mid to high frequencies. EQ, right? No!
Move the mics.
If you’re confident your snare and bass drum mics are positioned correctly
(snare mike: one inch above the rim, one inch over the edge, pointed towards
the center and slightly down, bass drum just in front and slightly off
center) it’s almost always the overheads that are giving you trouble. Pull
them outwards by a foot and note the difference. Keep doing this in one
direction or the other until you feel things are markedly improved. Tom
mikes can also wreak havoc, as they are even closer to the other mics. I’ve
recently found that miking the rack tom on the top and the floor tom from
underneath yield very consistent results. These mikes should also be pointed
towards the center of the drum but with a much more vertical angle. As
always, try not to listen to each drum mic solo’d separately, but with all
of them on. The drums are essentially one instrument and all your moves and
decisions should be made within that context.
Acoustic guitar too boomy? First off, move the mike away from the “sound
hole”. That’s actually a bass port, someplace to let air and energy escape
from the instrument. The true sound of the guitar is radiated from the face
of the guitar, or soundboard. Stick your ear where you would put a mike.
Move you head around until you hear where it’s sounding the sweetest. Now
move your head closer and farther away. When you think you’ve found the best
spot, stick a mike there.
Remember, no one listens to an instrument with their ear stuck right up next
to the instrument anyway, so if you’re going for an accurate representation
of a violin for example, you might try pulling the mike away. In this
instance, you’d get less of the sometimes irritating scrape of the bow, and
a bit more of how the fiddle sounds in the room, yielding a decidedly more
pleasing tone. Horns also benefit from this approach, especially saxophones,
whose sound emanates from the middle of the instrument, rather than the
bell. Flutes actually mic best near the player’s lips.
Vocalists often use a microphone’s proximity effect (wherein the closer one
gets to the mic, more bass frequencies are exaggerated) to impart intimacy,
but too close and it’s a muddy road you’re traveling. Move back six inches.
How’s that? Are you really rockin’ in the chorus? Step back two feet. You
get the picture.
Look at all those subtle improvements to the sound, and we haven’t even
thought about EQ yet. Now, remembering that subtracting certain frequencies
is almost always preferable to adding others (for all the reasons stated
above), you can season to taste. Yum!
Sven-Erik Seaholm is an award-winning independent producer with well over
200 recording credits, as well as a
singer and
songwriter. |
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