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THEORY & PRACTICE
With extreme age or wear, gaps can form in the foil or spiral shield of a microphone cable, allowing RFI
and EMI to leak through, or shield wiring can begin to make intermittent contact with the signal wire,
causing a parasitic effect. XLR pins can corrode, even turn colors, after many years of exposure to the
elements, or solder joints break at the stress points inside of an XLR barrel. Occasional cable testing
and maintenance is good practice, and worn XLR pins can often be given new life (if not past the
point of no return) by cleaning or spraying liberally with a contact cleaner such as DeOxit and worked
through several insertions. It is good practice to not use a cable much longer than what is needed for
the job at hand; if a 15 ft. cable will work, little good can come from using a 40 ft. cable instead.
Though condenser microphones are far better equipped to survive longer or lesser quality cable runs
than their dynamic and ribbon counterparts, audio can begin to attenuate or become contaminated
beyond a certain threshold.
MICROPHONE PLACEMENT AND SPACING
When it comes to distancing a microphone from its sound source, one may think of this
process as choosing a desired ratio of the sound source to reflections in the acoustic space.
The closer to the source, the less space and ambience will be captured. In some cases, this is
fully desirable; and ambience will be added in later via the magic of digital delay and reverb.
Natural acoustics are critical. A great illustration of this is the recording of a gunshot or cannon fire. At
very close range the sound is surprisingly thin; however, at a distance, the sound becomes more full
and explosive. This is a great reference to keep in mind because to some degree this phenomenon
holds true with anything where natural acoustics is an important part of the sound, most notably with
percussion. All processes do have boundaries, however, microphones have a maximum SPL level they
can be subjected to before distortion begins. Microphones and preamps both have a signal to noise ratio
that tends to get poor in cases where more gain is required to make up for a distant signal.
What a microphone hears will often be radically different from what a casual observer hears when
standing several feet back from the microphone. It's good practice to get down and put one's
ear close to a speaker cabinet or right in front of a bass drum's resonator head, and hear what
that microphone is hearing from its perspective. Get a sense for how different your source
sounds close up, farther back, and from different angles. Begin to move a microphone around
very slowly and listen for the changes in sound that you get. Notice how a small change in mic
position can make an under-snare microphone go from bad to good. Notice how moving a
guitar cabinet mic further to the side of the center cone, or further off axis will affect the sound.
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