Kurzweil K2000 - MUSICIANS GUIDE - Page 264

DSP Functions
Filters
14-12
PARAMETER RANGE OF VALUES
COARSE ADJUST ± 10800 cents
FINE ADJUST ± 100 cents
KEY TRACKING ± 250 cents per key
VELOCITY TRACKING ± 10800 cents
SOURCE 1 Control Source list
SOURCE 1 DEPTH ± 10800 cents
SOURCE 2 Control Source list
SOURCE 2 DEPTH CONTROL Control Source list
MINIMUM DEPTH, SOURCE 2 ± 10800 cents
MAXIMUM DEPTH, SOURCE 2 ± 10800 cents
Gated Lowpass Filter (LPGATE)
You may be familiar with gates as applied to effects like reverb, where the effect shuts off
abruptly after a speciÞed time. The gated lowpass Þlter produces a somewhat similar effect in
terms of the soundÕs amplitude. The ÞlterÕs cutoff frequency is controlled by the AMPENV.
When the AMPENV is at 100%, the cutoff frequency is high, so most of the partials are heard.
When the AMPENV decays or releases to 0%, the cutoff frequency is low, so only the lowest
partials are heard. YouÕll hear the distinct effect of the Þlter closing as the amplitude envelope
releases.
One-pole Highpass Filter (HIPASS)
High-frequency partials pass through this Þlter unaffected. At the cutoff frequency, the signal is
attenuated 3 dB. ThereÕs a roll-off of 6 dB per octave below the cutoff frequency. The resonance
is Þxed at -3dB. When the cutoff frequency is well above the the highest-frequency partials of a
sound, raising the cutoff further will not affect the timbre of the sound, but will merely
attenuate it further.
The Coarse Adjust parameter sets the cutoff frequency in terms of a key name. The remaining
parameters (except Pad) alter the cutoff frequency in increments of cents. Positive key tracking
values raise the cutoff frequency for high notes and lower it for low notes. More speciÞcally, a
value of 100 cents per key on this page, when Þltering a constant waveform like a sawtooth,
would result in waveforms of exactly the same shape for all pitches of the waveform. The cutoff
frequency moves in sync with the frequencies of the waveformÕs partials as different pitches are
generated. Negative key tracking values will steepen the rolloff of highpass Þlters below the
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
10 100 1000 10000 100000
Frequency in Hertz
Amplitude in dB
Cutoff frequency
from C 2 to C 7
C 2 C 7