Skip to content
blzr docs

Build: VODER Voice

A complete VODER (Voice Operation DEmonstratoR) speech synthesizer in a single module. Implements Homer Dudley’s 1939 source-filter architecture: a glottal pulse buzz (-12 dB/oct rolloff) and white noise hiss are crossfaded by MIDI CC1, fed through 10 patent-accurate bandpass filters (CC20–29 per-band amplitude), and output through a master compressor (CC7 volume). A MIDI note input controls pitch. Generate MIDI control data from English text using the text-to-midi.bb pipeline.

Step 1: Add MIDI input

Section titled “Step 1: Add MIDI input”

The MIDI node receives note events for pitch control. Note On/Off sets the oscillator frequency via the pitch output.

Nodes added: vv-midi

Step 2: Build the excitation stage

Section titled “Step 2: Build the excitation stage”

A glottal pulse oscillator (buzz) and white noise (hiss) are each routed through gain nodes. A mixer amp sums both sources. MIDI CC1 crossfades between them: 0=voiced, 127=unvoiced.

Nodes added: vv-osc, vv-noise, vv-buzz, vv-hiss, vv-mix, vv-cc1, vv-inv, vv-flip

Connections: 10 new

Step 3: Build the 10-band filter bank

Section titled “Step 3: Build the 10-band filter bank”

Ten cascaded bandpass filter pairs (24 dB/oct each) with non-uniform spacing from the 1940 VODER patent. Each band’s gain is controlled by MIDI CC20–29.

Nodes added: vv-flt-0a, vv-flt-0b, vv-amp-0, vv-cc-0, vv-flt-1a, vv-flt-1b, vv-amp-1, vv-cc-1, vv-flt-2a, vv-flt-2b, vv-amp-2, vv-cc-2, vv-flt-3a, vv-flt-3b, vv-amp-3, vv-cc-3, vv-flt-4a, vv-flt-4b, vv-amp-4, vv-cc-4, vv-flt-5a, vv-flt-5b, vv-amp-5, vv-cc-5, vv-flt-6a, vv-flt-6b, vv-amp-6, vv-cc-6, vv-flt-7a, vv-flt-7b, vv-amp-7, vv-cc-7, vv-flt-8a, vv-flt-8b, vv-amp-8, vv-cc-8, vv-flt-9a, vv-flt-9b, vv-amp-9, vv-cc-9

Connections: 40 new

Step 4: Add spectral tilt

Section titled “Step 4: Add spectral tilt”

A lowshelf filter at 3 kHz applies spectral tilt controlled by CC74 (Brightness). CC74=0 is flat, CC74=127 applies −24 dB tilt. All 10 band outputs feed through the tilt filter before the master volume.

Nodes added: vv-tilt, vv-cc-tilt, vv-tilt-mul

Connections: 12 new

Step 5: Add master output

Section titled “Step 5: Add master output”

The tilt filter feeds into a master gain controlled by CC7 (Volume), followed by a compressor as a safety limiter.

Nodes added: vv-vol, vv-cc7, vv-comp

Connections: 3 new

Step 6: Group into a module

Section titled “Step 6: Group into a module”

Select all 47 nodes and press g. Expose the compressor output as the module’s audio out.

What you just built

Section titled “What you just built”

A reusable VODER Voice module with 3 exposed parameters and 1 exposed port.

Select it in the Module Library (SPC m) to add one to any patch.

Next steps

Section titled “Next steps”