Alesis S4 Stroller User Manual


 
Editing Programs
QuadraSynth Reference Manual 69
¥Ê Aftertouch Pressing on the keys after theyÕre down generates this control signal.
Aftertouch is also called channel pressure, and represents an average of all keys
being pressed. This affects any keys that are held down. The harder you press on
the keys, the greater the degree of modulation.
¥Ê Polyphonic Pressure This is similar to aftertouch, but each key can respond to
individual pressure messages. Although the QuadraSynth keyboard does not
generate poly pressure, the sound generators can respond to poly pressure
signals entering via the MIDI In. Example: Assign poly pressure to the soundÕs
amplitude in a string ensemble patch. You can then increase the level of selected
notes of a held chord to ÒpullÓ some notes out of the chord.
¥Ê Pitch Wheel The two wheels to the left of the keyboard are modulation sources
(see below). The leftmost wheel, Pitch, always controls the oscillator pitch but
can be tied to other parameters as well.
¥Ê Modulation Wheel The rightmost wheel, Modulation, is traditionally assigned
to LFO amount (level) so that rotating the wheel away from you introduces
vibrato. However it is also well-suited to controlling timbre, vibrato speed, and
many other parameters.
¥Ê MIDI Volume MIDI can produce a variety of controller messages (see the MIDI
supplement in the back of this manual). Of these, controller #7, which controls
channel volume, is one of the most frequently used. Example: Assign the filter
cutoff as the destination, and you can have the signal become less bright as it
becomes lower in volume.
¥Ê Sustain Pedal The sustain switch plugged into the sustain pedal jack provides
this modulation signal.
¥Ê Pedal 1 The pedal plugged into the Pedal 1 jack provides this modulation signal.
Typically, this may be mapped to AENV Amp to act as a volume pedal.
¥Ê Pedal 2 The pedal plugged into the Pedal 2 jack provides this modulation signal.
¥Ê Pitch LFO This is the same modulation signal provided by the Pitch LFO. The
Frequency LFO and Amplitude LFO can also be selected as modulation sources.
¥Ê Pitch Envelope This is the same modulation signal provided by the Pitch
Envelope. The Frequency Envelope and Amplitude Envelope can also be
selected as modulation sources.
¥Ê Random This provides a different modulation value every time you hit a key.
Example: With vintage analog synth patches, use pitch as the destination and
apply a very slight amount of random modulation. Each note will have a slightly
different pitch, which simulates the natural tuning instability of analog circuits.
¥Ê Trigrate This is a Trigger Rate Follower, which monitors how fast notes are
being played on the keyboard. For example, if routed to the Effect send of a
Program, you could automatically have more effect when playing slowly, and
less effect when playing quickly.