Alesis QuadraSynth Plus Filter

Editing Programs: Chapter 6

QuadraSynth Plus Piano Reference Manual 85

Filter Filter (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.

Tip: 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. 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.

When 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 on, the filter frequency tracks the keyboard pitch.

Therefore, if using the filter creates a particular harmonic

structure when you play one key, playing a different key will

shift the filter frequency to maintain the same harmonic

structure.

At +00, velocity has no effect on the filter cutoff. With positive

values, playing harder increases the filter cutoff. More positive

values drive the cutoff frequency higher for a given amount of

velocity. More negative values drive the cutoff frequency lower

for a given amount of velocity.

Tip: Many acoustic instruments, such as acoustic guitars, sound

brighter when you play them more forcefully. Adding a little