Working on an audio processor for driving an 807-based modulator. The modulator's frequency response is pretty Hi-Fi, so I'll need to filter pretty heavy to keep from eventually sending out a very wide signal. (-3dB points are 38hz to 29Khz at 45W out of 65W design output!) Currently, I have a four-pole version of the all-pass phase rotation filter, of the type suggested by W3AM Here: http://www.w3am.com/8poleapf.gif From there, I need to do some high-pass filtering and ditch everything under 80hz, and some low-pass filtering to cut everything off over 4.5Khz. This should be my "brick wall" filter, to make sure I'm never much wider than 10kHz on the air. To do this, I've got a 4th order sallen-key filter for both the low and high pass filters-that's 24dB/octave slope. But, the limiter/compressor is what is eluding me. Is a simple diode clipper followed by the high-pass filter going to be OK? Or do I need to dive deeper into variable gain amps and the like?