LinPlug Spectral - Manual (Page 53)

However you can also simply “play” a chord with a different velocity for
each note.
So it should also be possible to arpeggiate the notes with the velocity at
which they are actually played. This is achieved by setting the Velocity
parameter to its full right position (P means Played), in which case the
velocity of each step in the arpeggiator has no meaning or is overridden.
On the other hand, the full left setting means that the velocity at which the
chord is played is meaningless and the velocity of the notes is determined
only by the arpeggiator (A means Automatic).
Adjusting this parameter somewhere between these extremes gives you
the rhythmic variations of the steps combined with the expression of the
actually played chord.
Note: “Velocity” values of Off and Tie keep their meaning, no matter the
actual value of the Velocity dial.
Swing
This adds a swing effect to the notes being played, so within a given clock
the odd step numbers (notes) are lengthened while the even ones are
shortened or vice versa; this is much more easy to explore than to explain,
please use a pattern of 4 1/8th notes and play with the swing parameter to
hear the obvious effect.
The Arpeggiator will always adjust the first note (when its not exactly in
timing) so that the successive notes are exactly in sync with the song
position. This can be switched Off if desired in the Spectral's Options (see
the Lock Arpeggiator to Song Position option described on page 87).