Audio
Delay Stack / Fill
01 — Definition
Loudspeakers placed further back in a venue to give level back to the distant audience without driving the main PA into the red. Each delay position is time-aligned to the mains so its sound arrives fractionally after the direct sound from the stage — the ear goes on localising the front (the Haas, or precedence, effect). The calculation: distance from the mains / 343 m/s, plus a small offset of 10–20 ms.
02 — In the field
Set the delay time to distance divided by 343, plus about 15 ms, so the front source still wins the precedence effect. Without that small offset, listeners localise the delay speaker instead of the stage.