Voice cards expand the functionality of the Bullfrog and make it even more versatile. Some voice cards replace patch cables - they connect the Bullfrog’s "modules" internally, while others have built-in mixers, signal generators, and advanced electrical circuits to control the synthesizer. For example, the Sequencer sends CV to control pitch and gate to start events on the synthesizer, and the Sampler/Looper emulates reel-to-reel tape recorder functionality.

The HIGHPASS VCF voice card expands the sound processing capabilities of the Bullfrog by adding a highpass filter. This allows for exploring highpass and bandpass filtering. The voice card features typical VCF controls – CUTOFF frequency, RESONANCE, and CV LEVEL. The CV source switch allows selecting between three CV sources – envelope generator 2, Sample & Hold LFO, which is a pulse wave generator in the Sample & Hold “module.” The voice card includes internal audio connections that make patching less cluttered.

The ELECTRIC ORGAN voice card makes internal connections within the Bullfrog to emulate a pipe organ when several notes with octave intervals are played together. It also demonstrates the principles of ADDITIVE SYNTHESIS. In additive synthesis, several simpler waveforms are mixed to generate more complex sounds. The voice card features internal connections that make patching less cluttered.

The WIND AND STARS (NOISE) voice card makes internal connections within the Bullfrog so that it automatically emulates randomly evolving wind sounds, and blinking stars are controlled by the divider. Toddlers fall asleep better when they hear sounds like these.

Refer to the Bullfrog User Manual for more information on the voice cards.