LinPlug Spectral - Manual (Page 19)

Cross-Modulation
The Cross-Modulation is very important for Spectral's unique sound. For
each Oscillator (and as you will see later also for each Filter) you can
choose 2 cross-modulations with adjustable type, intensity and source.
On top of each Cross-Modulation dial you find the Type selector, which in
case of the Oscillators can be either
– AM (Amplitude Modulation)
– FM (true Frequency Modulation) or
– PM (Phase Modulation, sometimes in other synthesizers this is
called Frequency Modulation)
Amplitude Modulation (AM) can be used to produce rich and complex
waveforms. Frequency Modulation (FM) and Phase Modulation (PM) are
great for producing metallic, bell-like tones. In almost any case cross-
modulation raises the harmonic content, making a sound brighter.
Oscillator FM has a setting on the Spectral's Option page (described on
page 86) which has quite some influence on how it sounds.
The Dial itself sets the amount of Cross-Modulation which is also available
for modulation using the Mod Matrix (Osc / XMod Amt).
The source selector below each dial contains any of the four Oscillators
and any of the four filters. The output of the respective chosen source is
used as input for the cross-modulation.
Cross-Modulation Sources
Though it at first sounds simple to have either the Oscillator or Filter
as source there are a few things which are good to know:
When choosing the Oscillator you get the full Oscillator output, not
affected by the Oscillator Volume dial, the Oscillator Envelope, any
volume modulation via the Mod Matrix and of course no filtering.
When choosing the Filter you get the filtered signal, which is affected
by the Oscillator Volume dial, the Oscillator Envelope and any
volume modulation of the Oscillator via the Mod Matrix. However,
the Filter Volume dial and any Filter volume modulation via the Mod
Matrix does not affect this signal.