Royer Labs SF-2 - Manual (Page 9)

The Sweet Spot
Finding and Working with the Sweet Spot
The “sweet spot” is that perfect position where you put a microphone and the instrument you are
recording snaps into focus. There are only general rules as to where the sweet spot may be found
for any given microphone/instrument relationship, and usually experimentation reveals it.
The sweet spot can be extremely variable since it depends on the quirks of a given microphone
and a given room. Once the sweet spot is discovered, this placement can become a rule-of-thumb
starting point for future microphone placement with similar sound sources. Remember, if it
sounds good, it’s probably right. If it doesn’t sound good, move the microphone. It’s often more
effective to reposition the microphone than to start adjusting knobs. Knob twisting can affect
headroom and phase coherence and add unwanted noise.
The following is a list of variables that contribute to “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. Variation in ratio of direct to reverberant sound.
4. Tendency of a microphone to favor the nearest sound source due to a combination of the
above items, plus the influence of inverse square law. Inverse square law states that for each
halving of source-to-microphone distance, the sound pressure level quadruples.
Other Types of Microphones
For the same ratio of direct to reverberant sound, omni-directional microphones must be closer to
the sound source than cardioid or bi-directional microphones. Microphones should generally face
the sound source head-on. Otherwise reduced treble due to phase loss effect will result. The
exception here is for large condenser microphones, which often give the flattest response at an
angle of about 10-20 degrees (off axis), where phase loss and diffraction effect offset each other
somewhat.
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