8-3410 July 1998
In the ISP-100 EQ filters the bandwidth is continuously variable
from 1/12 octave to 3 octaves (which translates to Q between
17.3 and 0.404).
Boost and Cut
In the ISP-100 EQ filters the boost/cut is continuously variable
from +12 dB to -12 dB.
Peaked HighPass Filters
The Peaked HighPass filter supplied with the ISP-100 is designed to
provide bass boost appropriate for low frequency extension in
vented-box loudspeakers. As the input frequency is reduced, the
filter response rises toward the selected peak magnitude at
approximately the selected cutoff frequency, and then returns to a 12
dB/octave rolloff characteristic below.
Peak Magnitude
In the ISP-100 Peaked HighPass filter the peak magnitude of the
filter response is continuously variable from 0 dB to +20 dB. The
peak occurs at approximately the selected cutoff frequency
when the selected Peak Magnitude is large; it occurs at
somewhat higher frequency when the selected Peak Magnitude
is small. (If the peak magnitude is selected to be 0 dB, then the
peak occurs at infinite frequency and the actual magnitude at the
cutoff frequency is -3 dB.)
Figure 8-16
Peak Magnitude vs. Q relationship.
The relationship between Peak Magnitude and filter Q is shown
in Figure 8-16.