8

378 Chapter 24 Ultrabeat
The LFO section display shows the LFO waveform, the shape of which is governed by
the Shape slider located underneath it. Dragging the slider from left to right causes the
waveform to fluidly morph from a sine to a triangle, and then finally to a square wave
(with variable pulse width), including all variations in-between. At the far right hand
position of the Shape slider, the LFO produces random waveforms.
The LFO speed (Rate) can be set independently (Free) or synchronized (Sync) to the
Logic Express tempo. Clicking either button once activates the corresponding mode.
The Rate knob determines the speed of the LFO. Depending on the Free/Sync setting,
Rate is displayed in either Hz or musical (measure) units.
The Ramp knob determines whether the output signal of the LFO is faded in or out.
Ramp works in a bipolar fashion: turning it to the right increases the Attack time of the
LFO, turning it to the left decreases the Decay time. In its middle position, Ramp has no
effect on the LFO. The Ramp value is displayed in milliseconds in its parameter field.
An LFO normally oscillates constantly. On percussive signals it can, however, be
interesting to limit the LFO cycles to a defined number. Ultrabeat allows you to set the
number of LFO cycles with the Cycles parameter. After completing the defined number
of cycles, the LFO stops oscillating. Try small Cycles values, and route the LFO to Osc
Volume to create typical drum flams or hand claps.
The range of Cycle values extends from 1 to 100. Turning the knob to its maximum
value (all the way to the right) results in a permanent oscillation (an infinite number of
cycles). A Cycle value of 1 allows the LFO to function as an additional (albeit simple)
envelope generator.
The Cycle parameter can also determine whether the LFO (waveform) is started from
the beginning (at a zero-crossing point) with each note trigger, or whether it simply
continues oscillating. A Cycle value of Inf (Infinity) forces the LFO to run freely. It is not
reset by incoming MIDI note on messages. When Cycle is set to values under 100, the
LFO will be reset by each new MIDI note on message (Note On Reset).
It’s really a question of taste as to whether or not you choose to trigger an LFO cycle
from the same spot or just allow it to oscillate freely, regardless of phase. The random
element of free-running LFOs can make many sounds fatter. This, however, can come at
the expense of a percussive attack—an often undesirable quality in a drum synthesizer.
Note: You can, of course, use minor shifting of the LFO phase—with the Cycle value set
to Infinity—to your advantage, adding an analog character to a drum sound, for
example.