Full Bucket Music: FBVC Vocoder

German programmer and software engineer Björn Arlt began building VST plugins under the name Full Bucket Effects in 2010. Being a musician, and a synth enthusiast from a young age, he was drawn to analysing and building software synths. He now offers both synth emulations and effects as freeware through his website.

The Full Bucket Vocoder FBVC is a software simulation of the classic KORG VC-10 Vocoder. In 1978, KORG presented the VC-10 Vocoder. This neat little instrument was packaged in a MS-10 housing plus goose-neck microphone and keyboard that allowed for instant vocoding experience without attaching any other gear. The integrated Tone Generator was ‘fully polyphonic’, meaning that each key produced an individual Sawtooth wave, and could be mixed with an additional White Noise source. This served as the Carrier signal, while the microphone input provided the Modulator signal. Of course it was possible to replace both Carrier and Modulator with external signal sources.

The VC-10 also offered some more cool effects like Accent Bend, where the level of the Modulator signal ‘bends’ the pitch of the Tone Generator, and Vibrato for the Tone Generator — as well as Ensemble which also featured on the the PS-3100/3200, and Delta. It had some drawbacks though, like a missing voiced/unvoiced detector, and even potential design flaws. For example, the highest four filters of the vocoder section were only fed with the noise signal.

The microphone input signal (or anything fed into the first two inputs) of the FBVC plugin is used as the Modulator signal. This is analysed by 20 bandpass filters and their responses are converted into 20 control signals. The Tone Generator signal mixed with the Noise and the external signal (any signal you feed into inputs 3 and 4 of the FBVC) serves as the Carrier signal. This is then filtered by another 20 bandpass filters and their level is controlled in real-time by the control signals of the Modulator. These filtered carrier signals, summed-up and optionally send to the Ensemble effect, provide the output signal. 

Tweaked Section:

• Adjustable frequencies of all Analysis and Synthesis bands
• Adjustable levels of all Synthesis bands
• All Analysis and Synthesis bands can be switched to fixed levels
• Bias and Limit for filter output VCAs
• Attack and Release for Tone Generators
• Adjustable LFO rates for Ensemble effect

Features:

• 20 band full stereo vocoder
• 64 voice polyphonic built-in Tone Generator section
• Accent Bending and Vibrato effects
• Optional WAV file playback
• Fully tweakable Analysis/Synthesis section
• Tweakable Ensemble effect
• Supports MTS-ESP by ODDSound dynamic micro-tuning
• Resizable user interface (not N version)
• All parameters can be controlled by MIDI controllers
• Plugin supports Windows and macOS (32 bit and 64 bit)