What acoustic treatment really is

Acoustic treatment is the set of measures that modify how sound behaves inside a room. It has nothing to do with preventing sound from coming in or going out — that's soundproofing, a different problem solved with mass, decoupling and airtightness.

Treating a room means controlling:

The distinction matters because many people buy panels expecting to isolate themselves from neighbours — and panels don't isolate anything. If your problem is external noise, this article isn't for you. If your problem is how your room sounds inside, keep reading.

Why any domestic room sounds bad

A rectangular room with drywall walls, wooden floor and a flat ceiling is acoustically about as bad as it gets:

  1. Hard parallel surfaces → constant reflections and standing waves
  2. Small dimensions (20-40 m³) → very audible bass modes between 30 and 200 Hz
  3. Regular geometry → metallic flutter echo between opposing walls
  4. Scattered furniture → insufficient and uneven absorption across frequency

The result is an RT60 of 0.8-1.2 s (four times the home studio ideal), bass that changes by 15 dB depending where you sit, and a diffuse stereo image. Mixing there is like painting with dirty glasses.

The three treatment families (and when to use each)

1. Porous absorbers (acoustic panels)

They convert sound energy into heat through friction with a porous, medium-to-high density material (28-70 kg/m³). Their effectiveness depends on thickness: the thicker they are, the lower in frequency they reach.

When to use them: first reflection points (side walls, ceiling, front wall), rear of the room, and generally wherever you need to control mids and highs.

2. Bass traps (resonators and thick absorbers)

Bass cannot be absorbed with thin panels: it needs thickness or tuned resonance. The two options are:

When to use them: in the 4 vertical corners (minimum) and, if possible, in the 8 trihedral corners. Without bass traps, the bass will remain uncontrolled no matter how many panels you put up.

3. Diffusers

They scatter sound in multiple directions without absorbing it. They preserve a sense of space and stop the room from sounding dead. The most common are QRD (Quadratic Residue Diffusers) with variable-depth wells.

When to use them: on the rear wall (behind the listener) in medium and large rooms, once you have early reflections and bass under control.

The four key frequency bands you have to treat

| Band | Frequencies | Typical problem | Treatment | |---|---|---|---| | Sub-bass | < 80 Hz | Fundamental axial modes | Thick corner bass traps | | Bass | 80-300 Hz | Build-up, cancellations | Bass traps + 100 mm panels | | Mids | 300 Hz - 2 kHz | First reflection, colouration | 50-100 mm panels at mirror points | | Highs | > 2 kHz | Excessive brightness, fatigue | 25-50 mm panels or any absorber |

Most cheap "solutions" treat only highs. This makes the room worse: it becomes dull on top but just as uncontrolled in the bass. Spectral balance matters more than absolute absorption amount.

How to calculate how much treatment your room needs

The standard procedure uses the Sabine formula:

RT60 = 0.161 · V / A

Where V is the volume in m³ and A is the total absorption in sabins (equivalent m²).

Step-by-step procedure

  1. Measure your room: length, width, height in metres
  2. Calculate the volume: V = L × W × H
  3. Estimate current absorption: total surface × average coefficient (≈ 0.08 for an untreated domestic room)
  4. Set your target: 0.3-0.4 s for a music home studio
  5. Solve for the absorption you need: A_target = 0.161 · V / RT60_target
  6. Subtract the current value: ΔA = A_target - A_current
  7. Divide by the average absorption per panel: a well-placed 60×60 cm panel contributes ≈ 0.3-0.5 sabins at 1 kHz

Example: 4×3×2.5 m room (30 m³). Current RT60 ≈ 1 s. Target 0.35 s.

Practical case studies by room type

Music home studio (10-15 m²)

Podcast / voice room (5-8 m²)

Professional mixing room (20+ m²)

Living room with hi-fi system (25-40 m²)

Common mistakes that ruin treatment

  1. Treating only highs (thin pyramid foam) → spectral imbalance
  2. Saturating the room with panels → sounds dead and oppressive
  3. Forgetting the ceiling → vertical reflections matter as much as side ones
  4. Placing panels "wherever they look good" → ignoring first reflection points wastes absorption
  5. Buying before measuring → always measure RT60 with REW and a UMIK mic before investing

How to know exactly what your room needs

Doing this by hand is possible but tedious. Our acoustic configurator automates the entire process: enter dimensions, materials and listening position, and it returns the exact list of panels, bass traps and diffusers you need, with 3D placement. Free, no signup, in 2 minutes.

Acoustic treatment isn't magic or a matter of taste: it's applied physics with measurable numbers. Once you have the calculation, all that's left is buying the right thing and putting it where it belongs.