Filter Test; Filter Test Patch - Sequential Pro One Technical Manual

1-7 FILTER TEST
4 :
'
-.
z
-.
nBC L P 3 1 8
. . . . .
CUTO,,
nE,n,,mwcr r M " r L n m t Mtv.n.mm
L Y " Y * T LY"""7
# Y O U W T
mrm
I ~ L O Y F Y L *
9 n 1 1
~ T I ~ S W
m r n
=usr.nm arrx.mv
0 6 C B W" I
.
. ' E
**mu.. a.u.t
rnl '
. .
WT7.4
IIELIL.W
I F O
Figure 1-5
FBLTER TEST PATCH
1. Patch according to Figure 1-5. NOTE: Unless you play s t a c c a t o or switch to
RETRIG mode, the
envelope generator will not retrigger
2, R o t a t e FILTER CUTOFF knob 0
-
10, listening
for
sine-wave oscillation. The
superaudia range is encountered a t about 7 on t h e dial.
3.
Set
FILTER CUTOFF to 3.
Raise
FILTER KEYBOARD AMOUNT. As this knob is
advanced, t h e
notes
heard
will
approach t h e diatonic
scale
tones. W i t h KEYBOARD
A M O U N T set to 8, t h e scale should be fairly
accurate.
Leave
knob
set
to 8.
4, Hold a key and r o t a t e FILTER ENVELOPE AMOUNT 0
-
10. This should not detune
t h e pitch. If i t does detune t h e filter, look into t h e Filter Envelope Generator circuit
f a r
the
source of t h e offset. I t is normal t o hear a n
increasing
transient as
you
advance
ENVELOPE AMOUNT. This is t h e voltage peak between t h e ATTACK and DECAY
periods--which becomes audible because t h e Envelope Generator is being triggered.
Although t h e knobs
are
set
t o 0, i t still takes a finite time to cycle through t h e
ATTACK and DECAY periods.
Leave
knob set t o 2.
5 . Decrease
FILTER RESONANCE to
t h e point where oscillation stops and note dial
indication. I t should be between 5 and 6. Return knob to
10.
6 .
Increase
FILTER ATTACK knob t o
6 . This should give about 1-sec attack time, as
indicated by the pitch which gradually rises then "snaps back" to its starting pitch.
Return t o
0.
7. Increase FILTER DECAY knob t o 6. This should give abyut 1-sec decay time. Return
knob to 0.
/
8, R o t a t e FILTER SUSTAIN knob 0
- 10. I t should smoothly increase filter frequency.
Leave knob set t o 10.