i've been developing a pedal for Devin to play his guitar through loudly on 8.8.08 when we take over a biker bar called Popeyes in Peekskill, NY.
the basic idea has been to pre-amplify the signal with an inverter chip, possibly after filtering it with an R-C circuit. the signal is then used as a clock for a divider circuit, which is capable of dividing the signal by several octaves until it becomes a series of clicks and the sensation of tone disappears completely. the octaves that are perceived as stable tones then become gated (turned on and off) by the lower-than-audio-rate octaves. these pulsing, detuned versions of the input signal can then either get summed back together and amplified (as in the pedal), or sent to different speakers around a space.
i think another possibility for this thing could be to generate synthetic tones using the NAND gates as oscillators, and having the pitch of the incomming signal affect the overal speed, but not the fundamental pitch of the resulting pattern.
i was considering submitting a more complete schematic and recording of the circuit for the DVD version of Nic Collin's book, but i'm pretty sure it's too late, and it's not been quite perfected yet.
i played King Tubby with Soul Syndicate through it. the output signal no longer sounded like dub. occasionally when the vocals crackled through, i was reminded of Jamie Saft and Merzbow's duo recording, Merzdub, or perhaps some Panasonic. I will get a recording of something up soon. however, as you might have guessed, it's very unstable. i described the rules of the system in my abstracted, idealized language because i come from a computer programming background, when in reality that's only a point of view and systems don't all behave that way. it seems to lock on easier to higher pitched material, so i thought perhaps a guitar would take to it. i tested it with solo Derek Bailey, and the output signal no longer sounded like Derek Bailey, but it at least still sounded like a guitar. at least until it would get confused by softer material. i worry that a line-level guitar might not be enough to drive the circuit reliably. if that's the case then i'll put another pre-amp hex inverter stage.
i like this path because it reminds me of some granular things in the computer music world. it's really refreshing sometimes to work in a medium that's harder to control. in my computer music compositions, i've recently been focusing on allowing the system in place to be stochastic in nature, where the form merely determines a new table of probable outcomes. while this is all just peaches and cream, i'm getting proficient enough in that environment that i can occasionally predict it too well, and i need to introduce some more indeterminacy into the system. that being said, there have been some recent moments of pure exploration with supercollider. i have happened upon two parameters of granular synthesis that i hadn't really played with yet: envelopes and phase. i did a few experiments in the past with simple phase modulations of wavelets, but it seemed like more trouble than it was worth. oh how wrong i was. ditto with the envelope thing. more to come on that later.