LinPlug Spectral - Manual (Page 46)

This inversion is easiest to explain with an envelope as modulation source.
An envelope is unipolar, so when you apply it with a positive depth of for
example 1.000 the modulation will raise the destination parameter. With a
negative depth it will lower the destination parameter.
The modulation of Pitch has a special display for modulation depth: First is
the amount in semitones shown, then a colon and behind it the amount in
cents. In example a modulation depth of "2:40" means that the pitch is
modulated to a depth of 2 semitones and 40 cents. Still the mouse affects
both values simultaneously, for finer control use the Shift key on your
computers keyboard (more on this in the Controls chapter on page 12).
Modulations that have no effect are greyed out. The Tools menu of the
Matrix also contains a “Clean” entry, which allows you to clean the Matrix,
setting all modulations that have no effect to the init values.
Left of the Matrix are numbers prior to each slot, you see a grey arrow (or
rather a triangle pointing downwards) on the first page below slow 12 and
one pointing upwards on the second page above slot 13. They are to
switch between the two matrix pages and also indicate whether or not there
are any active modulations on the respective other page. If there is any
modulation, the arrow is dark, otherwise greyed out.