CV Control of an Atari Soundchip

Front Panel Design (Preliminary)

The Frequencies of the Pokey Synth

What does this picture mean?

The Pokey chip is a very basic digital synthesizer. As such, it only produces discrete frequencies. Each gray line in the picture shows approximately where a single Pokey pitch lies relative to the layout of a piano keyboard. Middle C is the keyboard note marked in gray. Channel 1 can produce so many pitches over the range of a piano that the lines form a solid gray block. Channel 2 is much more lo-fidelity and ends up quantizing higher notes to the nearest pitch it can actually play. The audio demos make this effect a little clearer.

Audio Files

1. Two Channels playing different parts
        -Channel 1 for "melody", Channel 2 for drums
2. Channel 1 Pitch Sweep
        -A smooth sweep
3. Channel 2 Pitch Sweep
        -Listen to how the resolution falls apart with higher pitch
4. Channels 1+2 Unison
        -Tuning, detuning, and playing arpeggios together
5. Envelope Speed
        -Showing how well the volume tracks CV
6. External Input
        -Drum loop before and after going through the Pokey
7. Noise Sweeps
        -Sweeping Channel 2 through all the noise variations