Room Reflection Analyzer

Visualize where sound reflections concentrate in your home theater room. See heatmaps of reflection density on every surface to identify treatment zones before buying a single acoustic panel.

Room Setup

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Room Plan (Top Down)

Speaker positions update as you change inputs. Heights are projected onto the floor plan (shown as purple dots).

How Room Reflections Shape Your Sound

Every speaker in your home theater radiates sound in a wide pattern. Only a fraction reaches your ears directly - the rest bounces off walls, ceiling, and floor before arriving as reflections. These reflections arrive milliseconds after the direct sound and can either enhance spatial impression or blur imaging and intelligibility, depending on their timing, direction, and intensity.

The difference between a good-sounding room and a great one often comes down to controlling where and how these reflections arrive at the listening position. This tool shows you exactly where to focus that effort.

What the Raytracer Does

The analyzer casts thousands of rays from each speaker position in a Fibonacci spiral pattern that uniformly covers the speaker’s dispersion cone. Each ray bounces off room surfaces up to twice (first and second order reflections), losing energy at each bounce based on surface absorption. The tool tracks every intersection point and maps them as a density heatmap on each surface.

Red and yellow zones on the heatmap show where reflections concentrate. These are the areas where acoustic treatment - absorptive panels, diffusers, or a combination - will have the greatest measurable impact on your room’s acoustic performance.

Reading the Results

Ceiling typically shows the highest reflection density in any immersive audio layout. Every bed-level speaker bounces off the ceiling, and height channels radiate directly from it. Ceiling treatment is usually the highest-ROI investment.

Side walls at the listening position show strong first-order reflection zones from the front L/R speakers. These reflections arrive 2-5ms after the direct sound and directly affect stereo imaging. Treating these zones is standard practice in any critical listening environment.

Front and back walls receive reflections primarily from surround and rear speakers. Treatment priority depends on your layout - 7.1 and above configurations send more energy to the back wall through the rear surround channels.

Floor reflections are naturally managed by carpet, rugs, and furniture in most rooms. If your floor is hard (tile, hardwood), the heatmap will show significant floor reflection density that a thick rug at the listening position can address.

Speaker Placement and the Room Plan

The top-down room plan shows your speaker positions calculated from standard Dolby recommended angles. The tool places bed-level speakers on walls by casting rays at the correct azimuth angles from the listening position and finding wall intersections. Height speakers are placed on the ceiling using both azimuth and elevation angles.

This automated placement gives you a quick sanity check - you can immediately see if your room proportions work with your chosen layout, or if certain speakers end up in impractical locations (too close to corners, bunched together on a short wall, etc.).

V1 Limitations

This is a bare-walls analysis using a simple rectangular room model. Real rooms have furniture, openings, and irregular surfaces that change reflection patterns. The tool uses a hard dispersion cutoff rather than measured speaker directivity data, and traces at a single representative frequency (1 kHz).

Future versions will add surface materials, treatment panel placement, measured directivity for popular speaker models, and multi-frequency analysis. Even in its current form, the tool identifies the primary treatment zones that would emerge from any more detailed analysis - geometry drives the fundamentals.

Frequently Asked Questions

What does this tool show me?
The Room Reflection Analyzer traces thousands of virtual sound rays from each speaker in your layout and tracks where they bounce off walls, ceiling, and floor. The result is a heatmap for each surface showing where reflections concentrate. Red/yellow zones are treatment priorities - these are areas where acoustic panels will have the greatest impact on sound quality at your listening position.
How accurate is a shoebox room model?
For identifying treatment zones, a shoebox (rectangular) model is surprisingly effective. The first and second order reflections that matter most for acoustic treatment follow predictable geometric paths that the rectangular model captures well. Real rooms have furniture, alcoves, and openings that scatter energy differently, but the primary reflection zones remain consistent. Professional acoustic designers start with the same rectangular analysis before accounting for room details.
Why do I see more reflections on the ceiling than the walls?
The ceiling has line-of-sight to every speaker in the system - bed-level speakers bounce off it, and height speakers are mounted directly on it. Side walls only see speakers on their side of the room, and end walls see fewer direct paths. This is why ceiling treatment is typically the highest-impact investment in an immersive audio room, particularly for Atmos and DTS:X layouts.
What speaker layouts does this support?
The tool supports standard Dolby layouts from 5.1 through 7.1.6. Speaker positions are automatically calculated from Dolby-recommended angles relative to your listening position. 5.1 places 5 bed-level speakers, while 7.1.6 adds back surrounds and 6 ceiling speakers for full immersive audio. The room plan view shows exactly where each speaker lands in your room.
How many rays should I use?
The default of 3,000 rays per speaker gives reliable heatmap patterns for treatment planning. This produces dense enough coverage to reveal reflection hotspots without excessive computation. The tool runs entirely in your browser using a Web Worker, so there's no server load - a typical trace completes in under a second.
What about bass frequencies and room modes?
This tool traces mid/high frequency reflections (1 kHz representative) where geometric ray tracing is valid. Bass frequencies behave as pressure waves governed by room modes rather than ray-like reflections - they need different analysis. A separate Room Mode Calculator for bass is planned. For a complete treatment strategy, you need both: geometric analysis for panel placement and modal analysis for bass trap placement.
Should I treat every red zone on the heatmap?
Not necessarily. Prioritize first-order reflection zones at ear height on side walls near the listening position - these have the most impact on stereo imaging and surround envelopment. Ceiling zones above and between the listening position and speakers are next. Back wall treatment matters more for rear surrounds. The heatmap helps you allocate your treatment budget where it will make the largest difference rather than covering entire surfaces.