Sequential PRO 3, User Manual

Page: 36 / 168

24 Filters Sequential
Filters
The Pro 3 has three different filters, each of which has its own unique
character:
•
low
-
pass
1
-
4
-
pole ota
is a 4-pole, 24 db-per-octave resonant filter
based on the Sequential Prophet-6 filter. It can self-oscillate (generate a
sine wave) when
resonance
is set to its maximum.
•
low
-
pass
2
-
4
-
pole ladder
is a classic 4-pole, 24 db-per-octave resonant
transistor ladder filter. It can self-oscillate when
resonance
is set to its
maximum
•
state
-
variable
- 2
-
pole ota
is a 2-pole, 12 db-per-octave filter based on
the Sequential OB-6 filter. It features low-pass, band-pass, high-pass,
and notch operation. The State-Variable filter cannot self-oscillate.
Another characteristic of the State-Variable filter is that increasing the
amount of
resonance
does not decrease the amount of low-frequencies
(bass). On Low-pass 1 and Low-pass 2, increasing the amount of
reso
-
nance
de-emphasizes low frequencies. The
bp
and
state
controls apply
only to the State-Variable filter.
The differences between these filters can be subtle or dramatic, depending
on their individual settings, the amount of filter resonance applied, and
other factors. The function of the filters is to subtract frequencies from
the sound produced by the oscillators, noise generator, and/or external
audio input, thereby changing the overall harmonic content of the synth’s
sound. This change is varied over time using the Filter Envelope to
produce more dynamic timbres.