Assuming a voice is used via a microphone connected to the
external input, the Vocoder superimposes a replica of the
voice’s energy pattern on to the currently selected sound.
The voice signal known as the Modulator is fed to a bank of
band pass filters. Each of these filters, 12 of them in the A-
Station covers a set band in the audio spectrum from low to
high frequencies.
A program (for example a string sound) is known as the Carrier.
It is routed to another complete set of 12 filters that have the
same frequency band settings as the bank of filters used forthe
voice. Each of the outputs from the 12 band pass filters in the
modulator (voice) bank control the volume of each of filters in
the carrier bank.
It can now be visualized that, when a low frequency (extracted
from the voice by the modulator filter bank) is received by the
carrier bank, it passes the low frequency of the selected sound.
The other frequencies from the voice are treated in the same
way. This process creates the spoken or vocoded effect.
Adding a Vocoder effect to a sound
Ensure the function switch is set to SHIFT. Repeatedly press
KEY 5 until the display shows u d (Vocoder Balance) and an
alternating value. With a microphone or other sound source
connected to the input jack (this being the modulator), play a
note or chord on the connected MIDI keyboard (this being the
carrier). At a setting of 64, a mix of the Modulator and Carrier
will be heard - the Vocoder effect. At a setting of 0 the Carrier
only will be heard and at a setting of 127 the Modulator only.
Sibilance Level
Determines the amount of sibilance there will be in the vocoded
signal. Typically these are the ‘S’ type of sounds in speech.
Adding sibilance gives the Vocoder a more defined sound.
Sibilance Type
Determines if the vocoder uses real sibilance filtered from the
modulator or artificially generates it using noise. Set to h P and
a high pass filter is used to extract the sibilance from the modu-
lator (NOTE: this will allow some of the modulator signal to be
heard). Set to n o and Noise is used to artificially generate sibi-
lance.
Stereo Width
Determines how wide the stereo output of the vocoder will be.
The 12 bands of the Vocoder are panned one by one to the left
and to the right. Increasing the value moves the bands further
away from the centre position.
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Effects - Vocoder
Advanced features
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