Dave Smith Instruments Prophet 12 Bedienungsanleitung PDF herunterladen (Seite 30)

18 Low-Pass Filter

Dave Smith Instruments

Low-Pass Filter

The Prophet 12 features one analog resonant low-pass lter per voice. The lter

is switchable between 2- and 4-pole modes and has a dedicated ve-stage (delay/

attack/decay/sustain/release) envelope generator, capable of looping the delay,

attack, and decay segments. There are also controls for modulating the lter

cutoff with the keyboard and envelope amount with keyboard velocity.

4-Pole

—Selects the lter conguration. When lighted, the lter is in 4-pole

mode. A 4-pole, low-pass lter rolls off frequencies above the cutoff frequency

at a slope of 24dB per octave. When the button is off, the lter is in 2-pole mode

and has a slope of 12dB per octave and a more gradual roll-off of the higher

frequencies. Frequencies below the cutoff pass through unaffected, hence the

name “low-pass.”

Frequency: 0...164

—Sets the low-pass lter’s cutoff frequency over a range

of more than 13 octaves, stepping in semitones. The cutoff transitions smoothly

across the values when the frequency is swept.

Resonance: 0...127

—Emphasizes a narrow band of frequencies around the

cutoff frequency. In 4-pole mode, high levels of resonance can cause the lter to

self oscillate. In 2-pole mode, resonance is much more subtle and self-oscillation

does not occur.

Key Amount: 0...127

—Sets the amount of modulation from the note data

received via MIDI to Frequency (the lter’s cutoff frequency). A setting of 64

will step the lter in semitone increments for each note, 32 would be quarter-

tones, and so on.

VelocityEnvelope Amount: 0...127

—Enables keyboard velocity to modu-

late the lter enveloPe amount.

Envelope Amount: -127...127

—Sets the amount of modulation from the

low-pass lter envelope to the low-pass lter frequency. The modulation amount

can be positive or negative, allowing for inverted envelope control.

Note: The low-pass frequency setting may limit the effect of the envelope

on the lter. For example, if Frequency is all the way up, a positive enve-

lope amount will have no effect on the lter.

Delay: 0...127

—Sets a delay between the time the envelope is gated on and

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Dave Smith Instruments Prophet 12 Bedienungsanleitung Seite 30