Vocoder

This is an implementation of a traditional analogue style vocoder. Two audio signals, referred to as a modulator and a carrier, are passed into the vocoder effect. The modulator is typically a voice and the carrier is typically a synthesizer. The modulator is analysed by being passed into a multiband filter (a bank of bandpass filters), the amplitude envelope of each band is tracked and a control function for each band generated. The carrier signal is also passed through a matching multiband filter, the set of amplitude envelopes derived from the modulator analysis is applied to the outputs of this second multiband filter.

The uppermost band of the filter bank is always a highpass filter. This is to allow high frequency sibilants in the modulator signal to be accurately represented.

The modulator signal is always the signal received at the left input channel. For best results it is recommended to use a high quality external microphone.

Carrier Source - Source used as carrier signal. Either an internal synth or an external signal. If external is chosen, audio is taken from the right input channel.

Filter Steepness – Steepness of the filters used for both analysis and carrier processing.

Synth Type – Type of oscillator used by the internal synthesizer. Choose between sawtooth, square, pulse or noise.

Base – Frequency of the lowest filter (both analysis and processing) expressed as a MIDI note number.

Num – Number of filters that constitute the multibank filters used during both the analysis of the modulator and the carrier processing.

B.width – Bandwidth of the bandpass filters expressed in octaves.

Spacing – Spacing between the bandpass filters expressed in semitones.

BPF – Gain of the bank of bandpass filters.

HPF – Gain of the single highpass filter.

Gate Input – Activating this switch will apply a noise gate to the modulator signal. This option might be useful if the microphone used in rather noisy, such as would be the case if using the built-in microphone on a laptop, or if working in a noisy environment.