by Ken Navarro

I love the sound of an acoustic guitar. Whether it’s the crisp strum of Freddie
Green on a 1943 Gibson archtop, a bright jangly steel string vintage Martin or
my warm, round, Rick Turner nylon-string, a great acoustic guitar sound is the
epitome of natural, pure sound, especially as it occurs in modern jazz. However,
capturing a natural acoustic guitar sound on a recording can be tricky,
especially for players taking advantage of the affordable gear that’s currently
available and doing the recording themselves.

Keeping in mind that the overall sound of any audio signal is no better than
the weakest link in its signal path, the first and foremost issue when recording
an acoustic guitar is the quality of the instrument itself. While it is
certainly possible to make a mediocre acoustic guitar sound acceptable, a great
sound won’t be captured without a great-sounding instrument. Once you have a
quality acoustic guitar you wish to record, the next step is to select the right
microphone to record it. A high-quality condenser microphone is the best way to
go. If you can only afford one great mic, I recommend the AKG C414. For the
money ($750-$900), it’s a spectacular mic. When using a condenser mic, remember
that you’ll need phantom power, and many mixing consoles supply at least a
couple of channels with phantom power.

The next issue to address is the acoustic environment. Without diminishing the
role of the room, the close miking nature of most acoustic guitar recording
reduces the importance of the room acoustics compared to recording a drum set or
a string section. If you do not have the luxury of a large, balanced-sounding
room, your best bet is to work in a small room with fairly dead acoustics. This
will minimize the reflected sound present in the recording and allow for more
control of the instrument’s sound based on miking techniques and mixing. In
rooms that have a good deal of reflected sound, try to minimize it by putting
sound-absorbing material on the walls. Hang heavy blankets or old quilts on the
walls to greatly reduce the reflected sound; this will allow you to control the
instrument’s natural sound.

Mic placement is critical to the success of a session. A good place to start is
by placing the mic slightly off-axis below the soundhole at a distance of 5 to
10 inches. Placing the mic too close to the soundhole tends to capture a boomy,
unnatural sound. Just the slightest change in the axis of a good condenser mic
can cause large differences in the frequency response. When recording, keep your
EQ as flat as possible and experiment with the position of the mic, particularly
the angle of the axis. Only use the EQ when absolutely necessary. For example,
if a particular guitar has too much energy in the bottom end, and mic placement
variations don’t reduce it enough, try rolling off some of the low end, say 3-6
dB around 100Hz. You shouldn’t have to reduce or increase high end; both the
guitar and the mic should be able to easily capture a full, natural-sounding
high end. Later, during the mixing process, adjustments to the EQ of the guitar
may be necessary depending on the other instruments involved in the mix and the
blend and balance you desire.

I recorded and mixed my last three CDs using one of the many digital recording
programs available for computers. I am a Mac guy and I currently use version
2.72 of Digital Performer. Headroom is a primary consideration in digital
recording of acoustic guitars. It’s critical that you do not overload the
digital input. The transient nature of acoustic guitars means that you can be
well below the 0dB threshold and then suddenly jump many dBs over with one note.
While some engineers might advise the use of limiting or compression to deal
with these transients, I am wholeheartedly against the use of these devices in
the recording process. Instead, take advantage of the virtually noiseless
digital environment and err on the side of recording the guitar a bit softer
than you might with analog recording gear. If you have ever heard the sound of
digital clipping, you will understand the importance of a great performance not
being ruined by stray transients. Regarding punching in/punching out in the
digital recording format, the nondestructive nature of digital recording proves
to be superior to analog recording. While it still pays to automate your punch
ins and outs, it is certainly not critical. As long as you are in the ballpark
you can adjust the punch points after the fact and apply custom crossfading as
necessary.

Once guitar tracks are recorded, they’ll need to be mixed with the other
instruments in the song. The primary issue here is the equalizing of the guitar.
If it’s a solo acoustic guitar piece or a sparse arrangement, the sound obtained
when recording the guitar is probably close to the desired sound in the mix.
However, if the guitar is part of an elaborate arrangement and mix, its EQ may
need to be altered to make it sit in the mix properly. For example, if the
guitar is the lead voice in the context of drums, loops, percussion, bass,
acoustic piano and keyboards, changes in the EQ will almost certainly be needed.
The guitar may have sounded round and rich in the low and mid ranges when it was
recorded but in the context of the other instruments it may be clouding up the
mix and its own clarity may be suffering as well. Rolling off frequencies below
60-100HZ will help. The area of 240HZ is also a hot spot for most acoustic
guitars; adjustments with parametric EQ may be necessary. On steel-string
guitars the area of 400-600Hz can be boosted to bring the guitar out in the mix.
I prefer digital mixing because it lets me automate many small changes to the EQ
of the guitar during a mix. For example, there may be a single phrase or even a
single note that needs to be brighter or darker. An EQ adjustment may be
programmed to automatically kick in at the precise moment.
Though I avoid the use of compression or gating during the recording of a
guitar track, I often employ small amounts of compression to acoustic guitar
tracks during the mixing process. Typically, I’m careful to only allow the
compression to kick in on the louder notes and passages, so the compression is
not being used or is subtle. I also employ digital reverb on virtually any
acoustic guitar that has a melodic role in the music. Depending on the song, I
may use anything from a short small room reverb to a long, rich concert hall
reverb. My personal choice is the Lexicon PCM91. Occasionally I will add digital
delay within the reverb to create a thicker, more pronounced large room/chamber
quality. I try to create a combination of the delay and reverb that works
together in such a way that the digital delay is integrated smoothly within the
reverb.

Another useful effect in the digital mixing domain is pitch correction. These
plug-ins do wonders to seamlessly correct small and large intonation problems
inherent in even the best acoustic instruments. Be advised that any type of
polyphony, even octaves or unisons, will render some of these pitch correction
plug-ins useless. For consistent success, try to limit the use of digital pitch
correction to single note passages. Many digital recording applications include
software that will do pitch correction on polyphonic material but even so, some
experimentation and trial and error time is usually necessary to obtain a
seamless, transparent pitch correction on chords and octaves.