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Proportional-Q automatically
readjusts the amount of
boost or cut to keep the
subjectively perceived
loudness constant
Diagram 9:
Symmetrical frequency
responses at maximum boost
and cut and high Q (+/- 15dB,
Q5) for LF and HF bands.
Using low-Q values, automatically readjusts the amount of boost
or cut selected to keep the subjectively perceived loudness
constant.With constant-Q equalizers there is often only a limited
range of useable settings. Sometimes this is so narrow, you may
wonder why the Q control was not permanently fixed at the point
it sounded really good. Above that position it often starts to
sound harsh and peaky,and below with the broad bandwidth,the
sound is colored so you need to constantly re-set the boost/cut
control. Not so with proportional-Q. The Q control provides
useable settings over the entire range – giving you more versati-
lity to be creative. EQ adjustments with proportional-Q sound a
lot more musically related and offer a greater range of possible Q-
choices that really sound good and appropriate.Diagram 7 and 8
show frequency responses with varying Q and maximum B/C.
Tips on adjusting the bandwidth
Q adjustments are largely depending on the character of the
source material and whether processing single instruments or
vocals or final mixes.
Q values between 1 and 2 are useful to equalize vocals, guitars,
keyboard sounds and suchlike. When the bandwidth is broader
than half an octave it is easy to find and to manipulate the charac-
teristic elements.Very narrow Q values (Q3 to Q5) are often used
with high frequencies to eliminate disturbing frequencies within
cymbal sounds or to precisely emphasize the kick frequency of
the bass-drum or snare. Broader Qs are selected when boosting
dull source material which has lost high frequency content due to
de-noising,de-clicking and/or de-essing.To process bass frequen-
cies Q values are chosen between Q0.5 and Q0.8. Q values
between Q0,8 and Q1.2 are recommendable for frequencies
between 100Hz and ca.700Hz.
The BOOST/CUT control (B/C) of the LF and the HF frequency
band provides control ranges of +/- 15dB.
B/C (Boost/Cut)
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