How Room Studio works

Room Studio builds a 3D model of your room from the dimensions you enter, with furniture and TVs at their real sizes. It then finds the main seat (the one facing the screen most directly) and runs a set of checks. Scores are summaries for comparing layouts; every detail behind them is one click away in the studio.

The furniture and TVs

The catalog has 409 pieces. Real products, marked “✓ REAL” in the studio, use the dimensions printed on the manufacturer’s specification page, with the source and the date we checked it; generic pieces use typical sizes you can edit. Models are simplified shapes at the correct size, not exact replicas.

Viewing angle

The horizontal angle the picture fills from each seat: twice the arctangent of half the picture width over the eye-to-screen distance. Room Studio rates 30–40° as recommended (SMPTE ST 2080-3’s reference distance gives about 31–33°; THX recommends 40°), under 27° as small (Samsung’s relaxed rule), and over 61° as too close (the maximum for 4K cited in CEDIA/CTA RP22). Picture width for a 16:9 screen is 0.872 times the diagonal.

Mounting height and neck angle

The vertical angle from the seated eye to the screen’s center, compared with THX’s 15° guideline. Seated eye height defaults to 42 inches (Samsung’s figure), which we label as an assumption: it varies with the seat and the person. Cinema guidance (UNIC: 25° to the center and 45° to the top of the picture for a front row) is shown for context, not as a target.

Sightlines

For each seat, rays from the eyes to points across the picture are tested against the heads, seats and furniture in between. Head sizes and seated eye heights come from the ANSUR II anthropometric survey. Clearance over the row in front is reported as a C-value, the cinema measure in the UNIC handbook (200 mm good, 150 mm acceptable, 120 mm poor). Off-axis seats are rated against UNIC’s cinema classes, adjusted for display technology using RTINGS’ viewing-angle measurements.

Glare

Windows and lamps are reflected in the screen’s plane using the plane-mirror rule (angle in equals angle out); if the reflection of a light source lands inside the picture from a seat, it’s flagged for that seat. This shows where a reflection can appear, not how distracting it will be: that depends on the screen finish, the brightness outside and the content.

Speaker placement

Speaker angles from the main seat are compared with Dolby’s home-theater installation guidelines (front left and right 22–30°; 5.1 surrounds 90–120°, aiming for 110°; 7.1 side surrounds 90–110°; rears 135–150°; overheads by elevation) and ITU-R BS.775. Heights are compared with Dolby’s 1.2 m seated ear height. Soundbar gaps follow each maker’s manual.

Bass

Below about 200 Hz, Room Studio uses the standard modal model for a rectangular room: it sums the room’s modes, with damping from the room’s estimated low-frequency decay, between each subwoofer and every point on the floor at seated ear height. The bass map shows how even the bass would be at each spot. The same model powers our subwoofer simulator and the rules-of-thumb study.

Reflections and decay

Above the bass, first reflections are traced with the image-source method (Allen and Berkley): each speaker is mirrored in each wall, floor and ceiling to find where its sound first bounces on the way to each seat, with the delay and level. Decay time is estimated from the room’s volume and the absorption of its surfaces and furnishings (Sabine’s formula, with Eyring’s as a check), using published absorption data where it exists, and compared with CEDIA/CTA RP22’s target for the room’s size.

Suggestions

The improvement guide tries small changes (moving a seat, the subwoofer or a speaker, adding a panel or a rug) and re-runs the relevant check for each, then shows the ones that help most, one at a time, in the room.

What Room Studio doesn’t do

• It doesn’t replace measurement. Real walls flex, doors leak, furniture absorbs and scatters. The bass model assumes a rectangular room with rigid walls; L-shaped and open rooms are approximations.
• It doesn’t certify safety. Wall mounting, fireplace heat and electrical work need the product manuals and, where needed, a qualified installer. Room Studio flags fireplace heat but can’t measure it.
• Scores are estimates. No published standard combines all these factors into one quality score. Ours are built from the separate checks so you can see what drives them.

Sources

1. SMPTE (2017). ST 2080-3:2017 Reference Viewing Environment for Evaluation of HDTV Images.Standard
2. THX. Viewing Guide FAQ.Professional guide
3. CEDIA / CTA (2023). CEDIA/CTA-RP22 Immersive Audio Design Recommended Practice, v1.2.Standard
4. Samsung US Support. Where to mount the TV.Manufacturer
5. International Union of Cinemas (UNIC) (2021). UNIC Cinema Technology Handbook (v2).Professional guide
6. US Army Natick / Penn State Open Lab (2012). ANSUR II Anthropometric Survey of US Army Personnel (public data).Measurement
7. RTINGS.com. TV viewing angle test.Measurement
8. OpenStax. University Physics Volume 3, §2.1 Images formed by plane mirrors.Research
9. Dolby Laboratories (2018). Dolby Atmos Home Theater Installation Guidelines, r3.1.Manufacturer
10. ITU-R (2012). Recommendation ITU-R BS.775-3: Multichannel stereophonic sound system with and without accompanying picture.Standard
11. Room EQ Wizard. Room Simulation (modal simulator) help.Professional guide
12. Journal of the Acoustical Society of America (1979). Image method for efficiently simulating small-room acoustics (Allen & Berkley).Research
13. Journal of the Audio Engineering Society / Harman (2006). Loudspeakers and Rooms for Sound Reproduction — A Scientific Review (Toole).Research
14. Journal of the Audio Engineering Society / Harman (2006). Low-Frequency Optimization Using Multiple Subwoofers (Welti & Devantier).Research