I would classify this as an advanced project. This is not for beginners. There are 479 components on the PC board (at the current count).
This filter was designed to simulate the vocal tract of a human. To do this, there are three resonant filters that will be tuned to different frequencies. To make it so that the phonems can be selected via voltage control, there are three CV shapers on the board. These will allow you to make a more or less arbitrary function to control the filter frequencies. Now, I will be the first to admit that setting the function generators up is going to be a big pain in the ass!, and to do so will require the use of a scope with X-Y display capability.
Now, as of today (7-3-2001), I have not really tried this circuit out. Now, I did another breadboard of a simpler circuit a while back (you will find it elsewhere on this website), and the results were encouraging, but, not very spetacular. And, with 479 components, I am not sure if I want to build up a bread board, and due to layoffs at the place I am working, I have imposed a spending freeze, so PC boards are out of the question. So, for right now, this project is on hold due to lack of funds. As soon as I get the PC Board layout done, I will post the gerber files, and maybe some other brave sole will give it a try.
Building the Vocal Filter
Here are the most important file for building the vocal filter:
Board Schematic, BOM
Manual (updated 2-1-04)
Front Panel Schematic
Assembly Drawing (Reference Designators
Bill of Materials (Text)
MP3 Sample of Filter
Another MP3 Sample of Fileter (added 11-11-02)
And yet another MP3 Sample of the Filter (added 11-13-02)
And yet still another MP3 sample of the Vocal Filter (added 5-18-03)
And yet another MP3 Sample of the Filter, with some help from the Mikado Sequencer (added 4-14-03)
It should be noted that the above two MP3 file uses two oscilators tuned about 1 octave apart, an 8x2 sequencer, a 4 in 1 out mixer, 1 ADSR, 1 Multisegment Envelope Gnerator, and a VCA. These samples sounded so funny, I just had to post it.
And another MP3 Sample of the Vocal Filter (added 11-13-02)
Vocal Filter Board Picture