The E-Series EQ Module for 500 Series racks reproduces the legendary sonic signature of an early 80's classic, the Solid State Logic SL 4000 E console channel strip, which has featured on countless classic recordings from the 1980's to the present. The E-Series EQ Module features two different EQ's found on editions of the console produced between 1981 and 1989. Each EQ has unique response curves and tonal character. Historically the type of EQ fitted in an individual console was distinguished by the colors used on the LF knob caps so the two flavors have become known as the 'Brown' and 'Black' EQ's. On the E Series EQ Module you can switch between these two different flavors of EQ that have been loved by generations of professional producers.