Large path-length variation between listeners produces uneven sound pressure levels and feedback.

Evidence

The problem is that the path length variation is too large (2.2–30 m), and this results in a very high SPL variation. The arrangement would also have a very poor direct-toreverberant ratio over most of the audience and would be prone to feedback. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2523

Categorization

• DEFINE: SPL (sound pressure level) and direct-to-reverberant ratio are core psychoacoustic quantities; the passage grounds them in a concrete design consequence.