Tech Tools / Room Modes & RT60
Room Modes & RT60
Enter room dimensions. See axial, tangential, and oblique modes, Schroeder frequency, and Sabine / Eyring RT60 by octave band from surface materials.
Use at your own risk. Absorption coefficients vary by manufacturer, mounting, and air gap. Sabine/Eyring are statistical models that break down in very dead or oddly shaped rooms. Mode frequencies assume rigid rectangular rooms and c = 343 m/s (20 °C). This tool is a planning aid only. Always verify against manufacturer documentation and on-site measurements before deploying to a show.
- Volume
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- Surface area
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- Schroeder f
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- RT60 @500 Hz
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| Frequency | p,q,r | Hz | Type |
|---|
Sources
- Room mode formula: standard rectangular-room eigenfrequencies (Kuttruff / Everest).
- Sabine / Eyring reverberation formulas (metric constant 0.161 ≈ 55.3/c).
- Absorption coefficients: common published tables (e.g. sengpielaudio / architectural acoustics compilations of lab α values for concrete, carpet, gypsum, acoustic tile, curtains, etc.). Individual products will differ — verify with manufacturer data.
- Schroeder frequency approximation: fs ≈ 2000 √(T/V) (SI).
What this room acoustics calculator does
It lists low-frequency modes for a rectangular room and estimates RT60 by octave from material absorption coefficients.
Formulas
f = (c/2) √((p/L)²+(q/W)²+(r/H)²) with c = 343 m/s. Sabine / Eyring as above.
Worked example
10 × 8 × 3 m room: first length axial ≈ 17.2 Hz. With mixed gypsum / carpet / acoustic tile, midband RT60 often lands in the low seconds — check the chart for your finishes.
FAQ
What is an axial room mode?
A standing wave along one dimension: f = (c/2)·(n/L). Tangential uses two axes; oblique uses three.
Sabine vs Eyring?
Sabine: RT60 = 0.161 V / ΣSα (metric). Eyring uses −S ln(1−ᾱ) and is better when average absorption is higher.
What is Schroeder frequency?
Roughly fs ≈ 2000 √(T60/V) (SI), above which the sound field is more statistical than modal.
Tuning a room?
Kynetic handles speech intelligibility and PA design for live events.