Recording - August 2013 - 38

Figure 9. This is what an XY coincident pair of mics looks like, seen
from above.

mic is pointed straight ahead, and a bidirectional (figure-8) mic
picks up ambient sound from the left and right only, rejecting direct
sound from the instrument—the resulting recording is matrixed for
variable stereo width, and if collapsed to mono, only the center mic
ends up being heard, eliminating any phase issues. For more on
this, visit the resource section at recordingmag.com.
Isolation: divide and conquer
One issue that comes up to a much greater degree when recording acoustic guitar than when recording electric is isolation. With
electric guitar, the biggest problem is often the loud guitar amp bleeding into other mics during a band tracking session, and this can often

be addressed by isolating the amp in a booth. The amp’s close mic(s)
rarely pick up too much bleed, since the signal at the mic is so loud,
even with a small amp, relative to other sounds in the room.
With acoustic guitar, the opposite is true. The guitar is not usually loud enough to cause insurmountable leakage problems for other
instruments, but other instruments and sounds are much more likely
to leak into the guitar mics—since the guitar itself is not that loud,
and the mics are not that close, the leakage can become significant.
And since the player is “attached” to the instrument, it can’t be physically isolated without separating the performer as well.
Now, this is often done—the player can be put in a booth
within the larger tracking room, or surrounded with baffles
(a.k.a. gobos (go-betweens)), to block other sounds in the room
from reaching the guitar mics, which would be directional types,
positioned to minimize leakage (see below). Since monitoring is
usually done via headphones, these kinds of isolation techniques should not cause too many problems.
However, sometimes the player rejects this solution, needing to
maintain better eye contact with the other musicians, or a suitable
booth or baffles may not be available (I’m not even going to get
into the issue of live stage recordings; see Paul Vnuk’s article in this
issue). And of course, there’s the most tricky isolation issue of all—
the singer/guitarist who needs to sing and play at the same time,
but isolation between the voice and instrument is still required. Let’s
take a look at these situations and some possible solutions.
To dub or not to dub
Of course, the ultimate solution to any isolation issue with an
acoustic guitar recording is overdubbing. Having the player
perform the parts on his/her own, alone in the room, listening
to the previously-recorded tracks on closed-ear headphones,
eliminates any leakage problems, and allows for the most flexibility in miking techniques as well.

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Recording - August 2013

Table of Contents for the Digital Edition of Recording - August 2013