As discussed above, in a simple 1D plucking model, the plectrum comes
up and engages the string when
, and above some
maximum force the plectrum releases the string. At this point, it is
``above'' the string. To pluck again in the same direction, the
collision-detection must be disabled until we again have
,
requiring one bit of state to keep track of that.10.16 The harpsichord jack
plucks the string only in the ``up'' direction due to its asymmetric
behavior in the two directions [144]. If only
``up picks'' are supported, then engagement can be suppressed after a
release until
comes back down below the envelope of string
vibration (e.g.,
). Note that
intermittent disengagements as a plucking cycle begins are normal;
there is often an audible ``buzzing'' or ``chattering'' when plucking
an already vibrating string.
When plucking up and down in alternation, as in the tremolo
technique (common on mandolins), the collision detection alternates
between
and
, and again a bit of state is needed to
keep track of which comparison to use.