AEA RPQ2 Owner's Manual page 13

microphones when moved closer on-axis to a sound source become
more sensitive to low frequencies. This proximity effect, otherwise
known as "bass tip-up," becomes more pronounced the closer the
distance. With some large transducer microphones, such as the
AEA/RCA R44, proximity effect begins at six feet and is extremely
pronounced at a distance of one inch.
AEA RPQ2 LF Filter Response
LF filters can tame proximity effect and reduce other unwanted low-
frequency noise, such as air-conditioning rumble, traffic noise, "P-pops"
and breath-noise. However, a fixed-frequency, constant slope low-cut
filter cannot handle all situations effectively. The RPQ2 offers a flexible
LF filter that can be tailored to satisfy the varying and critical demands
of both speech and music.
Pushing in the LF Filter switch (ref. #5) inserts a -20dB (maximum) low-
cut shelving filter. The Low Frequency control (ref. #6) adjusts the -3dB
break-frequency of the filter.
Setting the filter is easy: push in the LF Filter switch and adjust the
tuning control until you like the sound. Then toggle the LF Filter switch
quickly to compare the result against the original.
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