It sounds like this is dynamic filter. Which means it is a filter that kicks in as a certian threshold is reached. It's sort of a compressor that works on a specific frequency. Kurt

Kurt: You mean similiar usage as a de-esser?

Perhaps the "setup" switch is for listening to the filters only as in what's been cut and "operate" switch is everything minus filters. That's how my BSS DPR 901 works.
Roly

Originally posted by falkon2:
Kurt: You mean similiar usage as a de-esser?

Yes! Othewise known as a frequency dependent compressor...

Originally posted by shmuu102:
...a 7 band notch filter ( model sc-68). it seems like a straight forward cut-only eq, except one knob that is labled "speed" (slow to fast of course). two other sets of switches labled setup and operation are almost as baffling.

:) Tag!

SC-68
Parametric Notch Filter
circa 1982

The SC-68 Parametric Notch Filter is a cut-only equalizer which is used to insert
relatively sharp dips in the frequency spectrum. As such, it is useful for removing
spot frequencies which cause problems such as feedback, cabinet resonances, hum or
TV sync signals, and single "hot" notes on musical instruments.

Specifications:
Amplitude: 0 to -30dB
Frequency: (low) 16Hz - 800Hz
(3/low-mid) 48Hz - 2.4KHz
(3/hi-mid) 160Hz - 8KHz
(high) 480Hz - 24KHz
Bandwidth: 0.3 octave - 0.03 octave
Input Z: 10K ohm active balanced bridging
Max Input-Output Level: +20dB (+5dB at max cut, full sharp)
Frequency Response: +/-0.5dB, 20 - 20KHz
Output Z: 50 ohm, term with 600 ohm or more
Hum and Noise: -87dBV (eq in), -95dB (eq out)
THD: <0.05%, +10dBV, 20 - 20KHz
Power: 120VAC, 50 - 60HZ, 5W
Shipping Weight: 12 lbs.

:) I bet the thing fades in and out of operation at speed set by the control. There is an insertion loss involved here too, of about 8 to 10db.

Love this old gear,

--Rick

Originally posted by Kurt Foster:

Originally posted by falkon2:
Kurt: You mean similiar usage as a de-esser?

Yes! Othewise known as a frequency dependent compressor... Got it! Thanks.