What is the proximity effect and how can we harness it, for good; for evil?
All microphones that have a cardioid polar pattern exhibit the proximity effect to some extent. As the performer comes closer to the microphone there will be a gradual bass tip-up, or increase in low frequency response. Most stage performance mic’s like the famous Shure SM58 are designed for very close-working vocals, and the proximity effect is partially reduced by designing extra presence into the high end that compensates for the proximity effect.
Some male vocalists actually like the rich sound that the proximity effect adds to the voice. But like drugs, there can be side effects to contend with. Too much proximity effect can make the vocals sound wooly, and lacking in clarity. If extreme “mic technique” is employed by the performer, then the vocal sound will become quite thin when used at a distance, compared with the usual close-up position. The engineer can compensate via EQ to some extent, but will never be able to get optimum voice quality from both close and distant positions with an EQ setting.
So how does the proximity effect work with studio condenser microphones?
Answer; it can be much more pronounced, to the point where if you try to use a close-up (“on the mic” ) technique you will get quite severe side effects.
The classic style vocal mic is a large diaphragm condenser like the Neumann U87 switched to cardioid pattern, or a U47, Rode NT1000 and the like. There are hundreds of less expensive substitutes nowadays, some that even give away free audio recorders.
These mic’s are very sensitive and will pick up wonderful subtleties in the voice, but will over-react violently to explosive consonants such as “P” “B” “F” etc. The result is a low frequency “POP” like a kick drum beat. Not only will the POP spoil the track, but it will sometimes stop the mic from working due to moisture getting into the capsule. (see my article on “How to avoid problems with studio condenser microphones)
Care should be taken with microphone placement and judicious use of POP screens to eliminate this problem. (see part 2)
Cardiod refers to the polar pattern in which the microphone is designed to operate. It means that the mic is uni-directional, and will thus reject sound coming from the rear of the mic (within certain specifications) and allow full frequency sound to be picked up only from the front.