Future Retro XS - Manual (Page 29)

ANALOG CONTROLS
FILTER MODULATION
The filter modulation section of the XS provides a way to animate the cutoff frequency of the filter.
KEY FOLLOW: The key follow control allows the filter cutoff frequency to track the pitch of notes
received from a MIDI keyboard, when this control is rotated fully clockwise. With this control rotated
fully counter clockwise, no key tracking will occur.
TIP: The key follow control can also be useful when the filter is set to self-oscillate, producing a sine
wave, so then you can play the frequency that the filter is generating. Although the pitch tracking of the
filter is not nearly as precise as your typical oscillator, for the most part, it will track decently over a
three octave range.
VELOCITY: The velocity control will determine the amount of effect that Velocity messages from a
MIDI keyboard will have when attenuating the amplitude of Envelope 1 routed to sweep the filter’s
cutoff frequency. The exception here is that if an external control voltage is inserted into the VEL IN
jack, this external control voltage will override Velocity messages received from the MIDI keyboard.
When this control is rotated fully counter-clockwise, Velocity will have no effect on Envelope 1’s
overall amplitude. When this control is rotated clockwise, the amount of effect that Velocity has on
Envelope 1’s amplitude will increase. Therefore, higher Velocity values will generate larger envelope
sweeps, while lower Velocity settings will generate smaller envelope sweeps.
TIP: Using external Velocity control signals that swing both positive and negative can have interesting
results. For instance, if the Velocity input goes negative and is controlling Envelope 1’s amplitude, it
will cause the output of this envelope to become inverted. However, negative control voltages applied to
Envelope 2 (the amplifier) will not allow the amplifier to pass audio to the output during the negative
period. If you do not desire this effect on the amplifier, simply turn down the Velocity control for the
amplifier.
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