Specifications

DR. REX LOOP PLAYER
191
Filter Frequency
The Filter Frequency parameter (often referred to as “cutoff”) determines which
area of the frequency spectrum the filter will operate in. For a lowpass filter, the
frequency parameter could be described as governing the “opening” and “clos-
ing” of the filter. If the Filter Freq is set to zero, none or only the very lowest fre-
quencies are heard, if set to maximum, all frequencies in the waveform are heard.
Gradually changing the Filter Frequency produces the classic synthesizer filter
“sweep” sound.
! Note that the Filter Frequency parameter is usually controlled by
the Filter Envelope (see page 191) as well. Changing the Filter Fre-
quency with the Freq slider may therefore not produce the expected
result.
Resonance
The filter resonance parameter affects the character of the filter sound. For low-
pass filters, raising the resonance will emphasize the frequencies around the set
filter frequency. This produces a generally thinner sound, but with a sharper,
more pronounced filter frequency “sweep”. The higher the resonance value, the
more resonant the sound becomes until it produces a whistling or ringing sound.
If you set a high value for the resonance parameter and then vary the filter fre-
quency, this will produce a very distinct sweep, with the ringing sound being
very evident at certain frequencies.
• For the highpass filter, the resonance parameter operates just like for the
lowpass filters.
• When you use the Bandpass or Notch filter, the resonance setting adjusts
the width of the band.
When you raise the resonance, the band where frequencies are let through
(Bandpass), or cut (Notch) will become narrower. Generally, the Notch filter
produces more musical results using low resonance settings.
Envelope Section
Envelope generators are used to control several important sound parameters in
analog synthesizers, such as pitch, volume, filter frequency etc. In a conventional
synthesizer, envelopes govern how these parameters should respond over time
- from the moment a note is struck to the moment it is released. In the Dr.Rex de-
vice however, the envelopes are triggered each time a slice is played back.
There are two envelope generators in the Dr.Rex, one for volume, and one for the
filter frequency (and/or pitch). Both have the standard four parameters; Attack,
Decay, Sustain and Release
! Please refer to the Subtractor chapter for a description of the basic
envelope parameters.
Amplitude Envelope
The Amp Envelope governs how the volume of a slice should change over time,
from the time it is triggered (the slice note starts) until the slice note ends. This
can be used to make a loop more distinct (by having a snappy attack and a short
decay time) or more spaced-out (by raising the attack time).
The Level parameter acts as a general volume control for the loop.
Filter Envelope
The Filter Envelope can be used to control two parameters; filter frequency and
overall loop pitch. By setting up a filter envelope you control how the filter fre-
quency and/or the pitch should change over time for each slice.
The Amount parameter determines to what degree the filter frequency will be af-
fected by the Filter Envelope. The higher the Amount setting, the more pro-
nounced the effect of the envelope on the filter.
✪ Try lowering the Frequency slider and raising Resonance and Enve-
lope Amount to get the most effect of the filter envelope!