M-Audio Microphone, User Manual

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Choosing & Using Microphones
Chapter 3
Basic Miking Concepts
Microphone placement is an area in which art meets science. Microphone choice and placement is
somewhat subjective, much in the same way that choosing a guitar and amp is a matter of personal
preference. Furthermore, each situation brings a difference confluence of performer, sound space,
recording equipment and creative forces. The question is not one of using the right or wrong mic
or technique, but simply one of what works best in each unique situation. Nonetheless, it s good to
know the rules in order to break them with the greatest success. Here, then, are some
generalizations to consider. Note that since condenser mics are used in the vast majority of studio
situations, all of the following application tips apply to condenser mics.
All recording spaces have a unique ambient quality that determines how sound from the source
will be reflected. Those reflections are candidates for being picked up in the microphone(s) along
with the direct sound from the source.The choice of microphone, pattern and placement depends
in part on the balance you wish to strike between the sound source and the ambient characteristic
of the recording space. Another critical consideration is isolation from other sound sources. In
many ways, it all comes down to envisioning the sonic focus you want the mic to have.
Close-Miking vs. Distance-Miking Techniques
In general,
close-miking
techniques (where the microphone is very close to the sound source) are
used in conjunction with a cardioid or super-cardioid to focus the pickup pattern on the source
while simultaneously avoiding any significant influence from the surrounding space. Close-miking
with cardioids (or super-cardioids for extreme situations) is also very useful in isolating the sound
source from other performers. Note also that the closer the mic is to the source, the more
prevalent with be the performance by-products such as breath, fret noise, snare rattles and piano
hammers. With close-miking, the illusion of space is likely to
be added electronically in post-production via reverb and/or
other forms of time-delay devices.
Placing any mic at a greater distance from the source will add
more of the room reflections.
Distance-miking
refers to
microphone placement intended to incorporate at least some
room reflections. An omni pattern really opens up the
recording to incorporate the full ambience of a room.
Regardless of the pattern, a proper balance must be found in
order to maintain the presence of the source while
incorporating surrounding ambience. When enough mics are
available,
engineers often employ both close- and
distance-miking techniques simultaneously in order to control
the balance of direct and room sound.
The farther the microphone is placed from the source, the
less sensitive it is to the sound emanating from that source.
This falloff is not linear. Microphone sensitivity exhibits the
law of inverse squares
i . e. sound power reaching the
microphone varies inversely as the square of the distance
from the source. For example, the typical mic is exposed to
only one-quarter the sound power at twice the distance from
the source. (You can think of this as the aural equivalent of
the exponential falloff in light as you get further away from a
light bulb.)
Recall also that large-diaphragm cardioid microphones exhibit
Choosing & Using Microphones
Microphones potentially receive
reflections from the room and other
objects as well as sounds emanating
directly from the source
full
sensivitiy
4'
2'
1/4
sensivitiy
1/16
sensivitiy
Sound power falls off exponentially with distance
according to the law of inverse squares
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