Diffusing sound to create the dense, natural decay found in large rooms [3].

1st-order digital all-pass with (a = 0.5):

Most people reach for Kilohearts Disperser, but if you're on a budget, you to check out AllPassPhase by EnumMusic. What it does: Punchier Drums:

—that utilize all-pass filters to manipulate the phase relationship of a signal without altering its overall frequency balance.

An is a specialized signal processing tool that allows all frequencies to pass through at an equal level (unity gain) while shifting their phase relationship. Unlike standard filters that cut out bass or treble, an all-pass filter leaves the tonal balance of a sound untouched but changes how its different frequencies align in time. How All-Pass Filters Work Focusing on Phase: The All-Pass Filter - Technical Articles