Parametric EQ is described in the GSP-2101 Artist
Owner's Manual, pages 20, 21 and Figure 3-4. If you don't have a copy of
this manual, it's available for download in the files section of this
forum.
For each of the bands in a 1-band, 3-band, or 5-band parametric equalizer, there are 3 parameters; frequency (Hz), bandwidth (Q) and gain (dB).
The bandwidth (Q) parameter adjusts the narrowness of the bandwidth at the band frequency. High Q settings yield narrow bandwidths where the EQ has a minimal effect on frequencies either side of the band frequency. Low Q settings affect a broader bandwidth of frequencies.
If you refer to Figure 3-4 on page 21, remember that the curves are for a positive gain. For a negative gain, the curves are downwards and a mirror image of those in figure 3-4.
Parametric EQs are used in various factory
algorithms. See the Appendix at the end of the manual for block diagrams
of each of these algorithms. Algorithms #5, #6, #14, #15, #16, and #32
have Parametric EQs in them.
Hope this helps,
Graham