This condition is called the sweet spot because the microphone
and the sound source are in a harmony of sorts; the acoustic infor-
mation is exciting the microphone in such a fashion that the re-
sulting reproduction is very desirable, usually without the need
for additional equalization or electronic manipulation.
There are only general rules as to where the sweet spot may be
found for any given microphone, and usually experimentation re-
veals it. The sweet spot can be extremely variable since it de-
pends on the quirks of a given microphone and acoustics of a
given room. Once the sweet spot is discovered, this placement
can become a “rule of thumb” starting point for future micro-
phone placement with similar sound sources. Remember this: If it
sounds good, it’s probably right. If it doesn’t, move the micro-
phone. It’s often more effective to reposition the microphone than
to start fiddling with knobs. Knob twisting can affect headroom
and phase coherency and add unwanted noise.
The following is a list of variables that also account for “sweet
spot” effect.
1. Frequency response variations due to proximity effect.
2. Frequency response variation due to treble losses as a result of
absorption and “narrowing” of the pattern at high frequencies,
causing weakening of highs as the microphone is moved away
from the sound source.
3. Rise in treble response on-axis due to diffraction.
4. Loss of treble response off-axis due to phase-loss effect.
5. Variation in ratio of direct/reverberant sound.
6. Tendency of a microphone to favor the nearest sound source
due to a combination of these items, plus the influence of inverse
square law.
12
Summary of Contents for R-122
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