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Acoustic Reflector Panel Placement Calculator

Calculate the specular reflection point and incidence angle for a flat acoustic reflector panel, using the image-source method.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax
9.84 ft
Schematic, drawn to the proportions you entered — not to scale on screen.

Reflection point distance from source

21.87 ft

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This uses the geometric acoustics (specular reflection) approximation, which is only valid when the reflector panel is large relative to the sound's wavelength — at lower frequencies (long wavelengths), diffraction effects dominate and this simple geometric method becomes less accurate. A full acoustic design should be verified by an acoustics consultant, especially for critical spaces like concert halls or recording studios.

Angle of incidence/reflection from panel normal
65.77 °

For the dimensions entered, expect a reflection point distance from source of 6.67 m (from point below source). Moderate confidence — sound arithmetic, but allow for the variation any real site introduces. Set for United States against IRC 2024. The market selector changes both the units and the code cited.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Image-source (mirror) method for specular sound reflection: for a source and receiver on the same side of a flat reflecting plane, the reflection point along the plane is located at a distance from the point below the source equal to (horizontal distance × source height) ÷ (source height + receiver height) — this locates the point where the law of reflection (angle of incidence = angle of reflection) is satisfied, the standard geometric acoustics method used in architectural acoustic reflector design.

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Frequently asked questions

What is the 'image-source method' used here?
It is the standard geometric acoustics technique for locating a specular reflection point: for a source and receiver on the same side of a flat reflecting plane, the point where the angle of incidence equals the angle of reflection is found using similar triangles formed by the source height, receiver height, and horizontal distance between them.
When is this geometric method less accurate?
The geometric (specular) reflection approximation is only valid when the reflector panel is large relative to the sound's wavelength. At lower frequencies (long wavelengths), diffraction effects dominate and this simple geometric method becomes less accurate — a full acoustic design should be verified by an acoustics consultant for critical spaces.
What does the 'angle from normal' in the breakdown tell me?
It is the angle of incidence (and, by the law of reflection, the angle of reflection) measured from the panel's normal — useful for checking how steeply the panel needs to be aimed to redirect sound toward the receiver.