Dave Smith Instruments Sequential PROPHET X, Руководство пользователя, Страница: 110 / 172

98 Modulation Techniques Dave Smith Instruments
As oscillator 1 frequency-modulates oscillator 2, complex harmon-
ics known as sidebands are generated. The number, frequency, and
amplitude of the sidebands are controlled by changing the ratio of the
modulator frequency (osc 1) to the carrier frequency (osc 2), as well as
the amount of modulation. In other words, changing the pitch of either
oscillator 1 or oscillator 2 will have a dramatic effects on the sound, and
so will increasing or decreasing the
amount
in the mod matrix.
In the example above, as you increase the modulation amount, the
sideband harmonics generated are more non-linear, like those in metal-
lic instruments such as gongs and bells. This is why it’s easy to create
“metallic” sounds with FM.
To modify the FM sound even more:
1. In the
oscillators
section, slowly turn the
pitch
knob on Oscillator 1 to
raise its pitch. As you increase the pitch, the sound changes as different
sideband harmonics are generated.
2. Try setting Osc 1
pitch
to F#6 and Osc 2
pitch
to C3. The sound is now
similar to the classic FM electric piano sound.
3. To make it really sound like a classic FM electric piano, adjust the
filter, filter envelope, and amplifier envelopes appropriately:
4. Set filter
cutoff
to 0 and set filter
env amount
to 91.
5. Set filter envelope
attack
to 0,
decay
to 98,
sustain
to 32, and
release
to 90.
6. Set amplifier envelope
attack
to 0,
decay
to 84,
sustain
to 127, and
release
to 80.
7. Play some chords. Basic FM electric piano!
You can create much more aggressive sounds by using other waveshapes
(or samples), different tuning relationships between the oscillators (or
samples), and different amounts of modulation. You can also use the mod
matrix to route both oscillators and both samples to each other in differ-
ent configurations. The harmonic possibilities of FM are immense.