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the general signal level.
It is suggested to start with the Output Gain control in the one o'clock
position for a setting near unity gain. Note, however, that if you subse-
quently apply HF boost, you may need to reduce the Output Gain control
correspondingly to avoid system overload.
Using the LF Filter
The RPQ500 was designed to complement ribbon microphones perfectly.
AEA Big Ribbon
mics deliver sub-woofer lows, which the RPQ500
TM
renders faithfully. Such strong low frequency content can mask high
frequency intelligibility, so the tunable LF filter was engineered to reduce
low frequency energy to appropriate levels.
Directional microphones when moved closer on-axis to a sound source
become more sensitive to low frequencies. This proximity effect, other-
wise known as "bass tip-up," becomes more pronounced the closer the
distance. With some large transducer microphones such as the RCA-44
BX proximity effect begins at six feet and is extremely pronounced at a
distance of one inch.
LF filters tame proximity effect and reduce other unwanted low-frequen-
cy noise, such as air-conditioning rumble, traffic noise, "P-pops" and
breath-noise noise. However, a fixed-frequency, constant slope low-
cut filter cannot handle all situations effectively. The RPQ500 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 tuning control (ref. #6) adjusts the -3 dB
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.
In Line Input Mode, the LF Filter can be utilized to reduce low-frequen-
cy rumble and "muddiness" for more clarity and transparency.
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