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Studio Microphone Topics:
Treating your
signal path to the right Studio
Microphone is important to attaining
the sound your music calls for. This
Sweetwater Buying Guide includes
information that can help you choose
a Studio Microphone for your needs.
Since there's so much to consider
when purchasing a Studio Microphone,
don't hesitate to call
1-800-222-4700 for more
information.
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What's
a USB Microphone?
Probably one of the hottest
developments in recent
microphone technology has
been the USB mic. Yet it's
actually a fairly simple
item to describe. A USB mic
contains all the elements of
a traditional microphone:
capsule, diaphragm, etc.
Where it differs from other
microphones is its inclusion
of two additional circuits:
an onboard preamp and an
analog-to-digital (A/D)
converter. The preamp makes
it unnecessary for the USB
mic to be connected to a
mixer or external mic
preamp. The A/D converter
changes the mic's output
from analog (voltage) to
digital (data), so it can be
plugged directly into a
computer and read by
recording software. That
makes mobile digital
recording as easy as
plugging in the mic,
launching your DAW software,
and hitting "record!"
Click here to view USB Mics
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Condenser Microphone
The condenser microphone is
a very simple mechanical
system, with almost no
moving parts compared with
other microphone designs. It
is also one of the oldest
microphone types, dating
back to the early 1900's. It
is simply a thin stretched
conductive diaphragm held
close to a metal disk called
a backplate. This
arrangement basically
produces a capacitor, and is
given its electric charge by
an external voltage source.
This source is often phantom
power, but in many cases
condenser mics have
dedicated power supply
units. When sound pressure
acts on the diaphragm it
vibrates slightly in
response to the waveform.
This causes the capacitance
to vary in a like manner,
which causes a variance in
its output voltage. This
voltage variation is the
signal output of the
microphone. There are many
different types of condenser
microphones, but they are
all based on these basic
principles. One example of a
highly popular condenser
microphone is Neumann’s
U87, shown here.
Click here to browse Studio
Condenser Mics
Click here to browse Live
Sound Condenser Mics |
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Dynamic Microphone
A dynamic mic is one in
which audio signal is
generated by the motion of a
conductor within a magnetic
field. In most dynamic mics,
a very thin, light,
diaphragm moves in response
to sound pressure. The
diaphragm's motion causes a
voice coil that is suspended
in a magnetic field to move,
generating a small electric
current. Generally less
expensive than condenser
mics (although very high
quality dynamics can be
quite expensive), dynamics
feature quite robust
construction, can often
handle very high SPLs (Sound
Pressure Levels), and do not
require an external power
source to operate. Because
of the mechanical nature of
their operation, dynamic
mics are commonly less
sensitive to transients, and
may not reproduce quite the
high frequency "detail"
other types of mics can
produce. Dynamic mics are
very common in live
applications. In the studio,
dynamics are often used to
record electric guitars,
drums and more. One example
of a highly popular dynamic
microphone is Shure’s hand
held
SM58, shown here.
Click here to browse Studio
Dynamic Mics
Click here to browse Live
Sound Dynamic Mics |
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Ribbon
Microphone
A type of velocity
microphone. A velocity
microphone responds to the
velocity of air molecules
passing it rather than the
Sound Pressure Level, which
is what most other
microphones respond to. In
many cases this functional
difference isn't important,
but it can certainly be an
issue on a windy day. Very
old ribbon mics could be
destroyed from the air
velocity created just by
carrying them across a room;
today’s ribbon mics can
handle the rigors of daily
studio use. A ribbon mic
works by loosely suspending
a small element (usually a
corrugated strip of metal)
in a strong magnetic field.
This "ribbon" is moved by
the action of air molecules
and when it moves it cuts
across the magnetic lines of
flux causing a signal to be
generated. Naturally ribbon
mics have a figure 8 pick up
pattern. You can think of it
like a window blind; it is
easily moved by wind blowing
at it, but usually doesn't
move when wind blows across
it from left to right.
Ribbon mics were the first
commercially successful
directional microphones. One
example of a highly popular
ribbon microphone is Royer’s
R121, shown here.
Click here to browse Ribbon
Mics
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How to read a microphone frequency
chart
A microphone’s
Frequency Chart can tell you a lot
about which situations are
appropriate for a given microphone
and which situations are not. In
theory, Frequency Charts are
generated at the factory by testing
the microphones in an anechoic
chamber. An anechoic chamber is a
specially constructed room just for
audio testing. The idea here is to
create a controlled atmosphere where
each microphone can be tested
equally, so the room is completely
dead, without any form of sound
reflection. Generally, a speaker is
set up in front of the microphone
that is being tested and pink noise
is played (pink noise is all
frequencies with equal energy in
every octave). The microphone is
routed into a spectrum analyzer that
measures the output and a Frequency
Response Chart is produced. The
chart is usually over the 20 Hz to
20 kHz range, which is the range of
human hearing.
So, how do you read it? The
horizontal numbers in a Microphone
Frequency Chart represent
frequencies (again, usually over the
20 Hz to 20 kHz range) and the
vertical numbers represents relative
responses in dB (Decibels). As you
look at a Frequency Chart, you can
tell how a given microphone performs
at certain frequencies. How is this
information helpful? Well, let’s
look at the famous Shure SM57’s
frequency chart:
The frequency response of the
SM57 makes it especially good
for certain instruments such as a
snare drum because the fundamental
frequency of the snare resides in
the 150Hz to 250Hz range – right
where the SM57 Microphone Frequency
Chart shows that the SM57 response
is flat, or neutral. In other words,
at this frequency, what you hear
going into the microphone is what
you will tend to hear coming out –
nothing more, nothing less. The
presence bump to the right of the
chart is just where the frequency of
the “snap” of the snare resides. In
addition, its rolled off low end
makes it great for de-accentuating
the kick drum which is often very
close in proximity. This combination
is what most engineers are looking
for in a great snare drum mic – the
ability to capture the true sound of
the snare, accentuate its snap and
reject other instruments in close
proximity.
Cardioid
A microphone polar (pickup)
pattern. Characterized by
strong sensitivity to audio
from the front of the mic,
good sensitivity on the
sides (at 90 degrees, 6 dB
less than the front), and
good rejection of sound from
the rear, the Cardioid
pattern can almost be
visualized as a
"heart-shaped" pattern
(hence its name). The
ability to reject sound from
the rear makes Cardioid
patterns very useful in
multi-miking situations, and
where it is not desirable to
capture a large amount of
room ambience. Popular in
both studio and live use
(where rear rejection cuts
down on feedback and ambient
noise), Cardioid mics are
used for a very high
percentage of microphone
applications.Keep in mind
that like all non-omnidirectional
mics, Cardioid mics will
exhibit pronounced proximity
effect.
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Supercardioid
A polar pattern name used to
describe the pickup pattern
of some microphones. The
Supercardioid pattern is
very similar to, and often
confused with, the
Hypercardioid pattern. The
Supercardioid pattern is
slightly less directional
than the Hypercardioid
pattern, but the rear lobe
of sensitivity is also much
smaller in the Supercardioid
.
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Hypercardioid
A polar pattern name
typically used to describe
microphone pick up
characteristics.
Hypercardioid patterns are
similar to Cardioid and
Supercardioid patterns in
that the primary sensitivity
is in the front of the
microphone. They differ,
however, in that the point
of least sensitivity is at
the 150 - 160 and 200 - 210
degree positions (as opposed
to directly behind the
microphone in a Cardioid
pattern). Hypercardioid
microphones are thus
considered even more
directional than Cardioid
and Supercardioid
microphones. Hypercardioid
microphones are frequently
used in situations where
maximum isolation is desired
between sound sources.
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Omnidirectional
Literally, from all
directions. In audio,
microphones are said to be
omnidirectional if they can
detect sound equally from
all directions. An
Omnidirectional microphone
will not exhibit a
pronounced proximity effect.
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Figure-8
A microphone polar pattern
in which the mic is (nearly)
equally sensitive to sounds
picked up from front and
back, but not sensitive to
sounds on the sides. This
produces a pattern that
looks like a figure 8 on
paper, where the microphone
is at the point of crossover
on the 8. The pattern is
also known as
bi-directional.
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Large Diaphragm
Any microphone with a
diaphragm larger than (and
potentially including) 3/4"
is considered to be a Large
Diaphragm microphone. In
general, Large Diaphragm
microphones tend to have a
"big" sound that engineers
find especially pleasing
where a little more
character might be
advantageous, such as is the
case with most vocals. Large
diaphragms are generally
more sensitive than small
diaphragm or medium
diaphragm mics because of
the increased surface area.
A common myth is that large
diaphragm mics capture more
low frequencies than small
diaphragm mics. Sometimes
their coloration may make it
sound like this is the case,
but a properly designed
small diaphragm mic is more
likely to be accurate
throughout a wide range of
frequencies, whereas the
coloration of a large
diaphragm mic can tend to
enhance certain desirable
characteristics in a sound,
which sometimes amounts to
more apparent bass or low
end. While there are many
great Large Diaphragm
microphones available, AKG’s
C 414 B-XLS microphone
(shown here) is one example. |
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Medium Diaphragm
The definition of Medium
Diaphragm is a potentially
controversial subject.
Historically there have been
large diaphragm and small
diaphragm mics, but more
recently the medium size has
begun carving out its own
category, though not
everyone agrees on the
precise upper and lower
limits. Most professionals
and manufacturers agree that
any microphone with a
diaphragm near 5/8" to 3/4"
can be characterized as a
Medium Diaphragm microphone.
Generally speaking, Medium
Diaphragm microphones tend
to do a good job of
accurately catching
transients and high
frequency content (as a
small diaphragm would) while
delivering a slightly
fuller, round and
potentially warmer sound (as
a large diaphragm might).
While there are many great
Medium Diaphragm microphones
available, RODE’s
NT3 microphone (shown
here) is one example. |
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Small Diaphragm
While there are no final
standards regarding a
diaphragm size that defines
Small Diaphragm, most
professionals and
manufacturers agree that any
diaphragm smaller than 5/8"
would be considered a Small
Diaphragm. Generally
speaking, Small Diaphragm
microphones tend to do a
good job of capturing high
frequency content and
transients. They will tend
to have a bit more "air" to
their sound and often have
less coloration than medium
or large diaphragm
microphones. Most of this is
due to the reduced mass of
the smaller diaphragm, which
allows it to more closely
follow any air disturbances
it is subjected to. While
there are many great Small
Diaphragm microphones
available, Neumann’s
KM 184 microphone (shown
here) is one example. |
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