The Rupert Neve Designs 543 is a mono compressor / limiter module for the popular 500 Series format, taking its sound and control from the Portico 5043. This versatile comp can switch between feed-forward and feedback compression, RMS and Peak detection, and can go from gentle dynamic control to over-the-top brickwall limiting. Engage the sidechain high-pass filter to let low frequencies go through uncompressed for huge thumping kick drum and bass guitar sounds, or link two 543s together for a workhorse stereo mix compressor.