ALESIS QS8.1 - Manual (Page 136)

Part 8: Editing Programs
124 QS7.1/QS8.1 Reference Manual
F ILTER
The Filter function (press [70]) lets you control the tone of each Sound layer.
Filter Frequency (00 to 99) Page 1
This sets the filter's initial cutoff frequency. Lower values give a duller sound since
this removes more harmonics; higher values let through more harmonics, which
gives a brighter sound.
Note: This parameter interacts with several others. If you hear no change when you
raise the Filter Frequency amount, try lowering the Filter Envelope Depth on the
FILTER function's page 7 (push [ PAGE] once to find it).
Signals with complex harmonic structures are most affected by the filter. Examples: A
sine wave has virtually no harmonics so you will not hear any significant changes as
long as the filter cutoff is higher than the note pitch. If the filter cutoff is lower than
the note pitch, you will either not hear the note, or it will be very soft. A
harmonically-rich sample (such as brass or white noise) will be greatly affected by
the filter.
If the Filter Frequency is set to maximum, in most cases all other variables in the
Filter function will have no effect (unless you modulate them negatively). Most other
filter functions raise the filter frequency, and it can't be greater than 99. So if you
want to use filter effects, proper setting of this initial cutoff frequency is crucial. This
is the “baseline” from which all other filter parameters will raise or lower (open or
close) the filter.
If the Filter Frequency is set to 00, and no other parameters are set to raise it
dynamically, no sound will pass through the filter at all--there will be silence. If the
Amp settings are wide open and you can't hear anything, check the Filter Frequency
setting.
Since the waveforms in ROM are recorded at the brightest possible setting, in many
cases dynamic filtering is crucial to making a program sound natural.
Keyboard Track (On or Off) Page 2
When this parameter is set to OFF, the filter cutoff remains constant across the
keyboard. Higher notes will be more affected than lower notes, since the filter cutoff
is comparatively lower for higher notes than lower ones.
When this parameter is set to ON, the filter frequency will track the keyboard pitch
so that as you play different keys the filter cutoff will shift automatically. For
example, when you play a higher note the filter cutoff point will automatically be
raised somewhat.
TIP: