Operation Manual

DR. REX LOOP PLAYER
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LFO Section
LFO stands for Low Frequency Oscillator. LFOs are oscillators in the sense that they
generate a waveform and a frequency. However, there are two significant differences
compared to normal sound generating oscillators:
• LFOs only generate waveforms with low frequencies.
• The output of the two LFOs are never actually heard. Instead they are used for
modulating various parameters.
The most typical application of an LFO is to modulate the pitch of a (sound generat-
ing) oscillator or sample, to produce vibrato. In the Dr.Rex device, you can also use
the LFO to modulate the filter frequency or panning.
Waveform
LFO 1 allows you to select different waveforms for modulating parameters. These are,
from top to bottom:
Destination
The available LFO Destinations are as follows:
Sync
By clicking this button you activate/deactivate LFO sync. The frequency of the LFO
will then be synchronized to the song tempo, in one of 16 possible time divisions.
When sync is activated, the Rate knob (see below) is used for setting the desired time
division.
Turn the knob and check the tooltip for an indication of the time division.
Rate
The Rate knob controls the LFO’s frequency. Turn clockwise for a faster modulation
rate.
Amount
This parameter determines to what degree the selected parameter destination will be
affected by the LFO 1, i.e. the amount of vibrato, filter wah or auto-panning.
|Waveform |Description
Triangle This is a smooth waveform, suitable for normal vibrato.
Inverted
Sawtooth
This produces a “ramp up” cycle. If set to control pitch (frequency),
the pitch would sweep up to a set point (governed by the Amount
setting), after which the cycle immediately starts over.
Sawtooth This produces a “ramp down” cycle, the same as above but inverted.
Square This produces cycles that abruptly changes between two values, us-
able for trills etc.
Random Produces random stepped modulation to the destination. Some vin-
tage analog synths called this feature “sample & hold”.
Soft Random The same as above, but with smooth modulation.
|Destination |Description
Osc Selecting this makes LFO control the pitch (frequency) of the REX
file.
Filter Selecting this makes the LFO control the filter frequency.
Pan Selecting this makes the LFO modulate the pan position of the REX
file, i.e. it will move the sound from left to right in the stereo field.