Reverberation

Room acoustic treatment for home spaces

Once sound is inside a room, the question changes from "how do I keep it out" to "how does it behave here". Hard, parallel surfaces make speech harder to follow and music harsh. Treatment addresses that without adding mass to the structure.

Acoustic absorber panels installed across an office ceiling
Ceiling-mounted acoustic panels reduce reverberation. Source: Wikimedia Commons.

Reverberation in plain terms

Reverberation is the tail of sound that continues after the source stops, as energy bounces between surfaces. A bare room with tiled floors and plaster walls has a long tail; the same room with a rug, curtains and a sofa has a shorter one. Excess reverberation is what makes a kitchen feel noisy and a video call sound hollow.

Absorption versus diffusion

Two tools shape a room, and they do opposite things:

An acoustic absorber board
A porous acoustic board used for absorption. Source: Wikimedia Commons.
Treatment stages

Acoustic projects tend to move through clear phases: assess the room, identify the strongest reflections, place absorption, then add diffusion where the room has gone too dead.

Assess Locate Measure Treat Verify

Where to place absorption first

The most useful early placements address the surfaces that reflect sound directly back at the listener:

  1. First reflection points on side walls, found with the mirror method.
  2. The ceiling above the seating or desk, often the largest bare surface.
  3. The wall behind a desk for home-office calls, which colours the microphone.

Living room vs. small studio

Different goals for different rooms
SpaceTypical aim
Living roomComfortable clarity for conversation and television
Home officeClean voice for calls; reduced echo near the desk
Small studioControlled reflections without an unnaturally dead room

A note on over-treating

It is possible to add too much absorption. A room covered in foam can feel oppressive and dull, and low-frequency problems often remain because thin absorbers do little at bass frequencies. A balance of absorption and diffusion, with thicker absorbers in corners for low frequencies, usually sounds more natural than blanket coverage.