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 8-16Peak Magnitude vs. Q relationship.
The relationship between Peak Magnitude and filter Q is shown in Figure 8-16.
10 July 1998
