First reflection

Definition

First-arrival reflections smear imaging and dialogue. The “mirror trick” puts a helper on the sidewall: sit in the money seat, have them slide a mirror along the wall, and mark where you see the tweeter. That point is where an absorber or diffuser belongs. Geometry from speaker, seat and room width estimates the same spot. Treat left and right, then the ceiling bounce if you can. Floor reflections are often a rug.

Calculators that use this

• Speaker placement & acoustics

  First Reflection Point (Mirror Trick) Finder

  Estimate side-wall and ceiling first-reflection locations from speaker, seat and room geometry — the calculator version of the mirror trick.

• Speaker placement & acoustics

  Acoustic Panel Coverage Estimator

  Estimate how many panels you need from room size, target wall coverage and panel area. Cinema rooms often want 20–40%.

• Speaker placement & acoustics

  Stereo Speaker Equilateral Triangle Setup

  Turn listening distance into speaker separation for an equilateral stereo triangle, plus a 30° toe-in starting angle.