New add-on voice: SPO vox
29/05/2022
My first speech synth that got me hooked about them: the SPO256-AL2!
Back in the day, in the mid-’80s there was only one place to get electronics components: the Tandy Radio Shack store.
They would sell chips in individual packages accompanied by a printed datasheet (I still have mine).
They were selling the SPO256 Narrator which became quite popular and was used in many commercial speech synthesizers that were interfaced with microcomputers.
Soon I found a schematic to build a talking printer! It was entertaining to hear it speak for the first time!
Today I decided to create a new add-on board for Emy.
The chip has a great potential for making sounds: it sounds metallic, it can hold a phoneme until the next one and the pitch can be driven by an external oscillator.
(in fact, the most difficult part is finding these chips!)
After a few iterations on the breadboard and ad few revisions of the board itself, I came up with a design that add 2 new functions to the chip:
- pitch control via the external oscillator
- volume control via a digital potentiometer driving an OP amplifier
