2. the instrument of claim 1 wherein each of said first and second bandpass amplifier comprise: two four-order-state bandpass filters; means for individually adjusting gain of sid bandpass amplifier; means for selecting said center frequency of said selected portion of said acoustic spectrum; and wherein response of said bandpass filters at said center frequencies has a slope of 12-14 dB per octave.
2. the instrument of claim 1 wherein each of said first and second bandpass amplifier comprise: two four-order-state bandpass filters; means for individually adjusting gain of sid bandpass amplifier; means for selecting said center frequency of said selected portion of said acoustic spectrum; and wherein response of said bandpass filters at said center frequencies has a slope of 12-14 dB per octave. 8. The instrument of claim 2 wherein one said selected portion of said acoustic spectrum is passed and amplified by said first bandpass amplifier and a second selected portion of said acoustic spectrum is simultaneously passed and amplified by said second bandpass amplifier.