Shure PG42 Mode D'emploi page 8

Pad Switch
Low Frequency Rolloff
Proximity Effect
Unidirectional microphones such as the PG42 progressively boost bass frequencies by 6 to 10 dB
below 100 Hz when the microphone is at a distance of about 6 mm (1/4 in.) from the sound source.
This phenomenon, known as proximity effect, can be used to create a warmer, more powerful
sound.
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The pad switch helps prevent distortion from extremely loud sources,
such as when close-miking horns or drums.
The low frequency rolloff may be used for voice or medium- to high-range
instruments. It reduces floor rumble and low-frequency room noise from
heating and air conditioning systems. Also used to compensate for proximity
effect or to reduce low frequencies that make an instrument sound dull or
muddy.