In live event production, this is the acoustic zone running straight down the middle of the audience area between two spaced subwoofer stacks. Because the sound waves from the left and right arrive at the exact same time, they combine constructively to create a massive increase in low-end sound pressure. System engineers often have to adjust timing or deploy cardioid sub configurations to prevent this zone from overpowering the rest of the mix.
We need to spread out the subs to break up that power alley before the front of house gets entirely drowned in bass.
While this is strictly an audio phenomenon, lighting and stage designers must account for it when placing front-of-house mix positions or mapping out VIP seating.
Related terms
Board op
The person who runs the lighting console during performances, executing cues on the stage manager's call.
Flash and trash
Wry crew slang for busy concert-style lighting full of strobes, chases and fast moving-light effects.
Rider
An addendum to a performance contract detailing the technical and hospitality requirements for a production.