JVC SEA-20g 7 band graphic equalizer… Is this thing any good
It may be good for various spectrum control purposes: control the sound spectrum in your room resulting from loudspeakers/room acoustics reaction in the medium/high frequency ranges (not the “extreme low frequencies”! (see below)), control of any program in other frequency bands, for to correct various spectrum defects due to properties of different media or “eras” of recording, and simply spectrum imbalances in different releases, to your taste.
But except for a crucial facility for sound reproduction systems: with its “lowest” (left) slider at 60 Hz, it does not give the possibility to compensate, to a certain degree, the steep falloff of extreme bass in the system, typical for the absolute majority of loudspeaker systems on the market (usually from 70…50 Hz down to 30…20 Hz), and to attenuate, to a certain degree, probable “boosts” or “dips” in your room’s acoustics.
Such a possibility can be given by a good, even very reasonably priced, hardware graphic equalizer, meeting these minimal demands: at least 10-band (“octave”) or more bands; the “lowest” (usually the left) slider at not higher than 31 Hz; +/- 12 dB range.
The only precaution with equalizers, I think, is to not exaggerate extreme frequencies, for to prevent hearing or speakers damage, but only to compensate a lack, or to attenuate an excess, of some sound spectrum segment, to your impression.
