ST-1 Speak & Tweak is an emulation of the classic SP0256-AL2 speech chip that was a popular add-on for many home computers in the early 80s.
Speak & Tweak produces sounds using a crude model of the human vocal tract with 6 cascaded digital filters, white noise generator (breath) and tone generator. It contains 59 allophones which when concatenated correctly, can create most English words.
The result is a monotonic, robotic sounding voice that can be tuned precisely to any MIDI note, and is recognisable by anyone who's heard a speech chip from the early days of computing.
Version 1.1 also adds an audio input to allow you experiment with audio sources other than the built in pulse generator.
- Emulation of SP0256-AL2 and English rules
- Speed and pitch controls
- Lock tempo control (allows multiple voices to play at same speed, different pitch)
- Bucket Brigade Device (BBD) Delay
- Polyphonic use
- Single word per key modes
- Damage control to artificially detune the filters
- Slur CV input to repeat last allophone
- Pitch bend and after-touch support
- Low DSP usage
- Plenty of CV inputs
Version 1.1 Adds:
- Audio Input for vocoder style effects
- Tempo synchronised delay
Version 1.2 Adds:
- Pitch change on punctuation characters (',' '.' '!')
- Sync 8th and Sync Quarter modes to synchronise word playback to music tempo
Manual available here