M-Audio Microphone, User Manual

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Small Capsules
Small capsules
are typically those with diaphragm diameters of less than about 1/2 . Categorically,
they are extremely accurate through the audible range of 20Hz to 20kHz. Their poor signal-to-
noise ratio, however, requires tricks with electronics and relegates small capsules to being most
useful for measurement rather than recording.
Medium Capsules
Medium capsules
have diaphragms that are approximately 1/2 inch to 3/4 inch in diameter. Given
the right design and manufacturing, they typically exhibit flat frequency response from about 20 to
18k. Their diaphragms are also large enough to deliver signal-to-noise ratios acceptable for
professional use.
Large Capsules
Large capsules
have diaphragms measuring 3/4 inch to one inch or even greater. Since larger
diaphragms yield better signal-to-noise ratios and greater sensitivity without having to induce
additional gain stages, bigger is typically considered better. Large capsules also tend to produce
greater low frequency detail a quality that can t be measured so much as heard. Large capsules
exhibit a proximity effect (most predominantly in the cardioid polar pattern), meaning that they
tend to sound more boomy as they get closer to the source. Large diaphragm M-Audio mics
include the Solaris, Luna and Nova.
The Diaphragm
The
diaphragm
is a critical component because it is
responsible for responding directly to sound waves. The
sensitivity of a mic is partially related to the thinness of its
diaphragm. (Recall that the comparatively thin diaphragm of
a condenser is largely what makes this type of mic much
more linear and sensitive to detail than a dynamic
moving-coil mic.)
Originally, condenser diaphragms were made from very thin, light metal such as nickel. As
technology evolved, it became possible to use synthetic materials such as mylar in order to create
tissue-thin membranes. Since condenser diaphragms need to conduct electricity, these synthetic
materials have a thin layer of gold applied to them the thinner, the better. Most modern
condenser diaphragms are 6 to 12 microns in thickness. (A human hair is 40 microns in diameter.)
The M-Audio large capsule mic, the Solaris, employs a special ultra-thin 3-micron, highly resilient
mylar diaphragm. This delivers a degree of sensitivity unparalleled in the industry. (Physics dictates
that we employ 6-micron diaphragms in our Luna and Nova models.)
In the old days, manufacturers would apply the gold to the diaphragm using a process known as
sputtering. They would place the diaphragm substrate in a vacuum jar, atomize the gold, and then
blow the gold onto one side of the material.Today s vacuum chambers are far superior, allowing us
to use a refined technique where we place our ultra-thin mylar film in a complete vacuum and
evaporate the gold in such a way that it adheres uniformly to the mylar. The result is a diaphragm
that is we feel is the most sensitive in the industry.
Condenser diaphragms can be extremely sensitive to humidity and temperature changes. In order
to minimize that, we temper our diaphragms by baking them for specific times at specific
temperatures in order to insure maximum stability and performance.
The Backplate
In a condenser mic, the diaphragm is suspended over a
backplate
that carries one half of the
electrical charge that results in the capacitance. The backplates of the best classic condenser
microphones were made of solid brass. In an effort to cut costs, most modern manufacturers make
the backplate out of injection-molded plastic and metalize them in some way. Critical listeners
patented Disk Resonator boosts
high frequencies for full
frequency response
backplate
sound waves
3-micron evaporated gold
diaphragm
5
Choosing & Using Microphones