Carl Martin Classic Optical EnvelopeCarl got a call from an old guitar playing friend who said he didn't want to use his wah all the time, but wanted to have some of those effects available. Enter the Classic Optical Envelope, essentially a classic envelope filter (auto wah utilizing the same opto technology as the Opto compressor) for guitar or bass, with a bunch of cool options. The first footswitch is for fx on off (buffered), and the second to select between the three modes (High