Over the years, I have built a bunch of
effects using schematics from Craig Anderton's great book,
Electronic Projects For Musicians. Among my favorites were an
envelope filter, using his "Envelope Follower" to drive the "Super Tone
Control." I found this to be far more flexible than the usual commercial
"Auto-wah" products. In particular, the Super Tone Control offers a
multitude of configurations, including high-pass, low-pass, and
band-pass.
I had also built an envelope-controlled phase shifter, which I found far
more useful and subtle than the usual LFO-driven phase shift devices.
One project that I had not yet built, but which always intrigued me, was
the "Dual Filter Voicing Unit." The DFVU consists of two notch filters,
that can be set to sweep the frequency range in parallel, or in opposite
directions (creating a wah/reverse wah effect).
It occurred me that these components could be combined into a single
"Tone Shaper", sharing some components, and resulting in a synergistic
whole. This project is the result.
