In
electronic music, it is the act of
modulating the level of an
audio filter (like the
cutoff filter, for example) across a
signal in a constant fashion. This has the effect of changing the '
feel' of the
sound in a fluid, almost
subconscious, manner adding more
dynamic to the music. The filter sweep is damn near the heart and soul of
electronic dance music, and can be very musically effective when done correctly. This
technique is popular since in many cases a sweep can be applied
real time, thereby adding "live" control over
dynamics.
A filter can be slowly applied to build tension toward a climax, or can be modulated back and forth to add reckless intensity.
The specific effect of a filter sweep is dependent on the type of filter used.