A simple and effective compressor with classic controls auto gain compensation and preamp to overdrive it.
downloads:
MdspCompressor VST win32 (with GUI)
MdspCompressor VST macosx (with GUI)
Compressor AudioUnit macosx (no GUI)
there’s a side-chain version for vst win32 too here with 3 inlets, the third one being the side-chain. Not all host will accept to load it because of this. However any decent modular host should do the job, and I think it’s also possible in more classical hosts using routing to effect capacities.