MOTM

A tape head doesn't do anything special for you over a pickup. Here's one
way a P/V converter can work:

1. Filter out as many harmonics as possible so you can look at just the
fundamental frequency.
2. Use a zero crossing detector to analyze 1 or two complete cycles (here's
where the lag comes from).
3. Decide from the zero crossings your best guess as to what 1 cycle is
(here's where multiple chords and finger muffs freak it out). Use a high
speed clock for a time base to count how long it lasts.
4. Convert to either a midi note number or analog voltage through a software
or firmware lookup table.
5. Lather, rinse, repeat.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

> From: hodad1@...
>
> On a similar note:
>
> In an old Roland Users Group mag, there's an interview with Skunk Baxter
> talking about guitar synths.  He mentions experimenting with using tape
> heads as pickups for the strings.
> I'm not knowledgeable enough to know if a tape head can function as a
> pitch-cv converter or
> exactly what they were doing, but it sounded interesting--particularly if
> you've got a bunch of old dictaphones lying around.
>
> tomr