First reflection points

First reflection points are the exact spots on a room's side walls, ceiling and floor where sound from the front left and right speakers bounces once before reaching the listener's ears, arriving just after the direct sound. Because these reflections are strong and closely timed to the original sound, they can blur imaging and make dialogue or effects sound less precise than the speakers are capable of.

Finding them is straightforward: sit in the main listening position, have someone slide a mirror along the side wall at speaker height, and mark the spot where you can see the speaker reflected in the mirror. That spot is a first reflection point and a strong candidate for an acoustic panel, since treating it reduces the smeared, washy quality reflections add to a mix.

A common mistake is covering a room in acoustic foam randomly rather than targeting these specific points, which wastes panels on surfaces that were not causing problems while leaving the actual reflection points untreated. Over-treating a room can also make it sound unnaturally dead, so most home theaters only need panels at the identified reflection points plus corner bass control rather than full wall coverage.