Recording Acoustic Guitar

Hi Clement I hope this helps

The main difference is that the end treatment will be at a lower
frequency and you might opt for a little limiting and no compression.
Small Dia-Condensors are the way to go.
Watch out for proximity effect
The acoustic guitar is very much in style today. Crossing between folk,
pop and rock genres. While the acoustic guitar remains one of the most
simple instruments, it also remains one of the hardest to get a great
sound on in the studio. It's really not that difficult though if you
follow a few basic rules.


The sound you get has a great deal to do with the quality of the
player.
Choose an appropriate type and gauge of string for the instrument and
for the kind of sound you're after, and make sure that the guitar's
action is set up correctly so that it plays without buzzing. There are
many different types of steel-cored wound string, all of which have
subtly different properties. The most commonly used types on acoustic
guitars are bronze, phosphor bronze and nickel wound. An instrument
with lighter gauge strings (perhaps an 11 to 50 set) will generally be
easier to play, but the sound will be thinner and low in volume. On the
other hand, very heavy strings (perhaps a set beginning with a 15-guage
top E) can sometimes sound tubby and lacking in overtones on the wound
strings. The best compromise is usually the heaviest set of strings
which are still comfortable enough for the guitarist to play. Usually
starting with medium gauge strings will give you a decent sound.

The size of the acoustic guitar has a lot to do with the frequency
range that it projects. The bigger the guitar the more low end. These
guitars are most effective with strumming chords in the open position.
These "jumbo" guitars are normally strum with medium to heavy gauge
strings that are capable of producing more resonance due to the larger
amount of wood that will resonate sympathetically. A medium size guitar
will sound tighter and project the sound quickly which makes it great
for soloing.

There is also the nylon or better known as the classical guitar where
the top three strings are nylon. This type of guitar produces a mellow
and a very harmonically even sound. It obviously does not contain the
same amount of mid-range and high frequencies that steel-string guitars
have. Nylon guitars are becoming more popular in pop music due to their
capability to produce harmonic content in a frequency range that will
not affect the lead vocal. A great example of this is in the music of
Sting. In a song like Fragile the nylon guitar can be mixed tighter to
the lead vocal for it is not encroaching in the presence frequency
range of the lead vocal. If Sting were to use a steel-string instead,
he would have to lower the overall level of the guitar because of the
high frequency encroachment produced by the steel-string guitar in
comparison to the lead vocal. That would lower the musical harmonic
content of the guitar whereby it would separate the vocal melody from
the harmonic accompaniment provided by the guitar.

The 12-string guitar is the grand piano of the guitar family. Usually
played in a strumming fashion with a pick and chords in open positions.
The 12-string guitar works most effectively by itself or with little
accompaniment for it takes up a lot of the frequency and musical range.
If you already have a basic 6-string performance and you feel you need
a brighter guitar in addition try changing the 3 low strings with
lighter gauge and tune them up an octave (Nashville tuning). Try to
avoid capos', for I feel they tend to choke the sound of the guitar.
If the guitarist is using a pick, it is always worth trying one of a
different thickness. With strumming you will tend to get a more even
sound with a medium to light gauge pick. With soloing a thick or medium
gauge pick works best for incorporating dynamics.

Another thing to bear in mind is that the sound of acoustic guitar
recordings can depend a great deal on the environment in which the
instrument is played. Acoustic guitars thrive on live acoustics, and
insufficient natural reverb is a common problem when recording them in
small home studios. While artificial reverb can be used to liven up the
sound of a dead room, getting a sympathetic natural acoustic always
produces better results, even if you want to add more artificial reverb
later.
To get a more live sound out of your room, try to position the
guitarist so that the instrument is played close to some reflective
surfaces -- hard floors, doors and solid furniture can all help here.
If there is carpeting on the floor of your recording room try placing a
sheet of plywood on the floor and get the guitar player the take off
his/her shoes. Be prepared to have an additional pair of socks in case
of gross air pollution.

Most studios will have a broad range of different mics to choose from,
there are few dynamic mics capable of doing justice to the acoustic
guitar. It is best to use a small-diaphragm condenser mic for its
greater high-frequency accuracy, and one with an omni polar pattern for
a more transparent sound and removing any proximity effect. If the room
has bad acoustics you will need to use a cardioid to minimize the
influencing characteristics of the room.

Capturing a natural sonic balance from the guitar is very important.
There are different sounds coming from different places on the guitar
that are important in contributing to an overall natural sound. If a
mic is used too close to the guitar, the direct sound from that part of
the guitar the mic is nearest to will dominate the sound from other
parts of the instrument and from the room. You risk miking up only a
part of the instrument when what you're really after is the bigger
picture. Opposite if your mic is too far away from the guitar. You can
end up with a lot of room ambience, leaving the original sound distant
and unfocused. As for the specifics of mic placement, position your ear
as if it were the microphone while somebody else is playing the guitar.
Move your ear around to find the "sweet spot". A common approach is to
set up the mic around 6-8 from the guitar, with the capsule aimed
between the sound hole and where the neck joins the body. This will
usually produce a well-integrated sound -- the levels of direct and
reflected sound will be about right, and the sound hole's contribution
will be controlled because the mic doesn't point directly at it. If you
need more low-frequency content move the mic position closer to the
sound hole. If you need a brighter sound move the mic closer to the
12th fret for this is where the first series of harmonic overtones
originate that contribute more high-frequency content to he overall
guitar sound. If you have a pair of enclosed headphones that are very
accurate to a reference point that you have established, you can easily
experiment with tweaking this mic placement while listening for the
best sound. If you find a promising sound in this way, remember to
check it out on your monitors before committing yourself -- headphones
can sometimes be rather misleading. If you find a good position but
feel the sound is too dead try switching the pattern to omni and if the
opposite occurs switch the omni pattern to cardioid. Be careful to not
get too close for this will create an unnatural balance from the
guitar. If you are working with a studio musician they will most likely
have a custom-made guitar. Ask them where the "sweet-spot" is on
their guitar for the performance they are playing. If the guitar player
is soloing and moving up the neck try placing the mic closer to the
sound hole to give you a fuller sound of the guitar. This will
obviously compensate for the lack of low-end that the guitar can
produce when used in a soloing fashion.

Selecting a microphone depends on the size of the guitar, if the player
is playing open chords or soloing. If the player is strumming with open
chords use a pencil condenser. If they are soloing move to a large
diaphragm condenser. Dynamic mics simply don't cut it.




A guitar with a built-in pick up and a microphone will undoubtedly
create some phase problems. Experiment with moving the mic closer and
further away from the guitar. That will affect the phase relationship
of the two sound sources. Phase, he can be a tricky bugger.
This will work effectively if the guitar player is also singing whereby
minimizing the vocal leakage into the guitar microphone. If you are
cutting a track in a studio with drums try using the direct pickup only
and replacing it with an acoustic pickup in an overdubbing stage. Even
though direct pickups on acoustic guitars have come a long way I have
yet to discover one that sounds as good as a microphone pickup.

Stereo miking works well for solo applications. The XY technique is
good but still falls short due to its lack of direct sound access. It
will give you more of a big cardioid pickup but with less high-end than
a single mic. I have found placing a mic over the 14th fret and another
just slightly off-center from the sound hole provides a good starting
point for stereo pickup. Make sure both mics are pencil condensers, the
same model and miked with the same distance from the guitar. Also
incorporate a slight off-axis pickup.

The main challenge when using a stereo technique is to make sure that
all the different signals are in time with each other when mixed -- if
there are delays between signals, this could cause phasing problems.
Some prod/engineers get around this problem by placing all the
different mics at exactly the same distance from the guitar's sound
hole, and this can be successful.

As with any studio recording, the composition of the cue mix you feed
to the guitarist will be extremely important, so be prepared to take a
little time in preparing it -- given the sensitivity of the mics
traditionally used in acoustic guitar recording, it's easy to pick up
unwanted leakage from the headphones. Solo the recorded track to check
for this, and if there's a lot of leakage coming through (from a click
track, in particular) then consider turning down the overall headphone
mix level or using a different pair of headphones -- closed-back models
are obviously best in this application and reduce the possibility of
feedback.

Recorded acoustic guitar sounds will usually benefit from a little
processing. This should be kept to a minimum while recording, so that
you leave your options open for the mix. In recording roll-off any
problems in the low-end such as rumble by inserting a high-pass filter.
As always stated, it's always safer to leave EQ and dynamic processing
until the mixing stage.

Equalization of the acoustic guitar is very common but used very
subtly. The first thing to try is just rolling off some boominess bass,
if there is some, using a high-pass or shelving equalizer at 60-80Hz,
as this can prevent the compressor from working too hard and
maintaining an even harmonic balance. It can make a big difference, for
example, if other sounds in the mix have strong low mid-range
components, and if you listen carefully to rock or pop mixes that
include acoustic guitar, you'll notice that the low end is quite even.
Most acoustic guitars performing in a strumming or finger-picking style
have a mid-range and/or high frequency boost. With the mid-range use a
wide Q centered anywhere between 3 and 7K. If high-end is needed try a
shelving EQ from 8-12K which will produce a silky top-end sound. Be
aware of making the acoustic guitar brighter than the lead vocal, if it
is mixed at a loud level. If you need musical body boost in the
600-1.5K range with a medium Q. With acoustic solos you might need to
enhance the low end between 100-200Hz to add more body to the
performance especially if the guitarist is soloing high up on the neck.


With compression for strumming a ratio of 2:1 - 4:1 with a medium
attack and medium release should be used if required. Remember that the
transient sound of using a pick identifies the rhythmic component of
the performance. If the attack time was too quick it would create the
illusion that the guitar player is playing behind the beat. For soloing
you might need to limit the transients slightly, then EQ and then
compress. With processing on an acoustic guitar it should be done with
transparency in mind.

If the guitar performance is continuous strumming, there will most
likely be no need for reverb. Reverb may be needed if the recording was
made in a small room or studio. Mono recording can also be given a
sense of space and width by adding a little stereo reverb. Ambience
settings with pronounced early reflections are particularly effective
in adding life and realism to the acoustic guitar.
With strumming use a short pre-delay of 30-50ms and a bright reverb
with a 1-2 sec decay time. With a guitar solo use a pre-delay of
100-150ms with a warm reverb with a decay time of 2-4 seconds. De-ess
the send to the reverb if there is a lot of high frequency finger
noise.
Extra Attack To Rhythm Guitars