INSTRUMENT design – simple ‘tracking’ one-pole filter object
The OonepoleTrack object is a subclass of the Oonepole object that ‘tracks’ changes to the cutoff frequency or the lag time and performs computations to update them only when they change. This only works if the caller sticks to updating either the cutoff frequency (using the setfreq method) or the lag time (using the setlag method), not mixing calls to both.
See the Oonepole documentation for a more complete description of this filter.