Dual VCA (2VCA)
The DUAL VCA (2VCA) employs two high-quality VCA's. This module is an excellent inter-patch VCA, featuring very low noise and exponential response. It was designed as a small VCA function for use at various places within a system for internal VCA functions (as opposed to the VCA's for output mixing). Like the new Universal Audio Processor and the Cross-Fader this VCA has an audio taper that is an exponential curve with a 12 db per volt sensitivity throughout the range except below about .5 volts. Below this threshold, the output of the VCA will decrease rapidly to completely attenuate the signal. This response is perfect for our envelope voltage range and is responsible for exceptionally quiet operation. Control voltage rejection is very high, and the unit cannot be overdriven beyond a gain factor of two.
The UNIVERSAL AUDIO PROCESSOR (UAP) is the ideal VCA module for small Serge systems because it can function in the following ways:
- As two independent VCA's with separate signal and control inputs.
- As one equal-power stereo panner. This panner has one input routed to two outputs, in a proportion which is voltage controlled. The panner can be used for signal routing within a system or for the positioning of sound in a stereo field. A VCA controls the overall amplitude of the output signal.
- As a voltage controlled cross-fader. As one input signal increases in amplitude at the output, the other decreases.
The CROSS-FADER (XFAD) is an equal-power cross fade unit. The module has two signal inputs. As one signal increases in level at the output under manual or voltage control, the other signal decreases in level at the output. This effect is used to accurately fade one sound in while fading another out. Cross-fading with voltage control permits a smooth transformation between two different timbres. If a sound and its reverberated image (available with the Wilson Analog Delay) are sent through the cross-fader, the reverb mix can be voltage controlled. This effect can be used to modify the spatial characteristics of a sound event, from immediate presence to distant ambience. In addition to the cross-fade function, a VCA controls the output amplitude.