Acoustic Treatment Calculator — Panel Coverage, Bass Traps & Reflection Points
Room and treatment inputs
Your dimensions stay in this browser. No room or layout data is uploaded or stored.
Treatment plan
Coverage and quantities
- Wall + ceiling area
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- Available after exclusions
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- Target panel-face area
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- One panel face
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- Installed panel-face area
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- Panel overage above target
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- Bass-trap stack
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First-reflection coordinates
- Each side wall, nearer speaker
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- Each side wall, farther speaker
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- Side-wall placement band
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- Left ceiling point
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- Right ceiling point
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Side-wall distances start at the front wall. Ceiling coordinates are shown as distance from the room centreline and distance from the front wall.
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How to use the acoustic treatment calculator
- Measure finished inside dimensions. Use clear wall-to-wall and floor-to-ceiling distances. Keep length aligned with the front-to-back listening direction.
- Choose a planning coverage. The target applies to wall plus ceiling area after the entered door/window exclusion. It deliberately excludes the floor.
- Measure panel faces. Enter the visible width and height of one repeated broadband panel. Panel thickness affects performance but not this face-area count.
- Plan corner stacks. Select the vertical corners you can treat and enter one trap module's installed height. The result rounds each stack up to reach the ceiling.
- Describe the stereo triangle. The speakers and listener are assumed to be centred left-to-right. Distances are measured perpendicular from the front wall.
- Mark, verify, then measure. Transfer the coordinates with a tape measure, confirm the points using the mirror method, and measure the treated room before finalising the layout.
Panel, bass-trap, and reflection formulas
The calculator treats panel coverage as exposed panel face area divided by available wall-and-ceiling area:
Aavailable = 2(L × H) + 2(W × H) + (L × W) − Aexcluded
panels = ceil[(Aavailable × target %) ÷ (panel width × panel height)]
Bass-trap modules are a physical stacking count:
modules = selected corners × ceil(room height ÷ module height)
For each ideal flat boundary, the source is mirrored across that boundary. A straight line from the mirrored source to the listener crosses the real wall or ceiling at the calculated first-reflection point. This image-source construction models ideal specular reflection; it does not predict reflection level, diffusion, diffraction, or absorber effectiveness.
How to interpret the treatment plan
Coverage is an inventory tool, not an acoustical grade. Two rooms with the same covered face area can behave differently because porous absorber depth, density, air gaps, boundary construction, furnishings, and frequency-dependent absorption all matter. Choose the percentage as a budget or layout target, then evaluate decay time and frequency response.
Reflection coordinates are centres to investigate. A real speaker is not a point source, panels have finite size, and nearby desks or equipment create additional paths. Each side wall receives a calculated reflection from both speakers, so the result reports a band. One sufficiently wide panel may span it; otherwise use multiple panels or prioritise the points verified from the listening position.
The bass-trap result only fills vertical height. It does not decide whether a corner absorber is deep enough or effective at a problematic modal frequency. Compare the room's low-frequency measurements with the Room Mode Calculator, and treat calculated modes as frequencies to investigate rather than guaranteed peaks.
Model and installation limits
This planning estimate assumes a rigid rectangular room, flat specular boundaries, a centred symmetrical stereo layout, and point-like speaker acoustic centres. It does not model doors as open boundaries, sloped ceilings, alcoves, furniture, speaker directivity, absorption coefficients, reverberation time, structural transmission, or sound isolation.
Panels and corner traps can be heavy and may contain fibrous materials. Follow the manufacturer's mounting, fire-safety, handling, and ventilation instructions; use fixings rated for the wall or ceiling construction; avoid concealed wiring and pipes; and obtain qualified installation help when necessary.
Method references
- Aalto University Interactive Acoustics — image-source technique, explaining ideal specular reflection paths using mirrored sound sources.
- Genelec — monitor calibration and improving room acoustics, discussing early reflections, absorption, diffusion, and low-frequency treatment.
- Genelec — monitor placement, covering symmetry, reflective boundaries, acoustic-axis height, and room resonances.
Acoustic treatment calculator FAQ
What percentage of a room should acoustic panels cover?
There is no single percentage that works for every room. Use this field as a transparent planning target, not a recommendation. The right amount depends on the room, panel performance, intended decay time, existing furnishings, and measured response.
Does the coverage result predict RT60?
No. Face-area coverage does not include frequency-dependent absorption coefficients or the existing absorption in the room. Use the Reverb Time Calculator when you have suitable absorption data.
How are the first-reflection points calculated?
Each speaker is mirrored across a boundary, and the calculator finds where the line from that image source to the listening position crosses the real boundary. This is the geometric image-source method.
Why are there two points on each side wall?
The nearer and farther speakers can both reflect from each side wall. The two marks define a placement band; a wide panel may cover both, while a wider band may need more treatment.
Does the bass-trap module count predict bass absorption?
No. It only counts enough modules to stack through the room height in the selected corners. Trap depth, material, air space, boundaries, and room modes determine low-frequency performance.
Are my room dimensions sent anywhere?
No. The calculations, diagram, copy operation, and CSV file are produced locally in your browser.