Free Sabine Reverberation Time (RT60) Calculator

Q: What is a Sabin?

A Sabin is a unit of sound absorption named after acoustic pioneer Wallace Clement Sabine. One square foot of 100% sound-absorbing material (such as an open window where sound escapes completely) equals exactly 1.0 Sabin.

Q: Can NRC (Noise Reduction Coefficient) exceed 1.0?

Yes! Standard ASTM laboratory tests measure absorption per square foot of front face area. Thick acoustic panels (3" to 4") mounted with an air gap absorb sound through their sides as well as the front face, yielding measured NRC ratings between 1.05 and 1.20.

Q: What is the difference between soundproofing and acoustic treatment?

Acoustic treatment (RT60 control) controls reflections, echo, and reverberation inside the room so recordings and monitors sound clear. Soundproofing (STC isolation) blocks sound from entering or escaping the room using dense structural mass, decoupling, and airtight door seals.

Calculate room sound decay time (RT60) using Sabine’s formula and determine exact square footage of acoustic absorption panels needed.

📐 Room Dimensions & Target

Room Acoustic Target Preset

Length (ft)

Width (ft)

Height (ft)

Bare Room Surface Condition

Acoustic Treatment Panel Absorption (NRC)

📊 RT60 & Treatment Requirement

Untreated Bare Room RT60

0.93 Seconds

Target RT60: 0.30 Seconds (Needs Treatment)

Panels Needed

14 Panels (2' × 4')

112 sq ft of treatment

Surface Coverage %

13% Wall Coverage

Balanced studio acoustics

Total Room Volume: 1,632 cu ft (46.2 m³)

Total Boundary Area: 860 sq ft

Target Sabins Needed: 266 Sabins

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Understanding RT60 & Sabine Acoustics

RT60 is the international acoustic metric defining the time (in seconds) required for sound pressure level to drop by 60 decibels (dB) after the sound source abruptly stops. In an untreated room, reflections bounce between parallel walls, creating flutter echo and muddy reverb that ruins audio recordings.

The Sabine Equation

RT_{60} = \frac{0.049 \cdot V}{A} \quad \text{(Imperial: Volume in cu ft, A in Sabins)}

RT_{60} = \frac{0.161 \cdot V}{A} \quad \text{(Metric: Volume in m³, A in Metric Sabins)}

A = \sum (S_i \cdot \alpha_i) \quad \text{(Surface Area } \times \text{ Absorption Coefficient)}

Why Over-Damping a Room is Bad

Covering 100% of a room's walls in cheap 1-inch foam creates an unnaturally dead, claustrophobic acoustic space that only absorbs highs ($>2\text{ kHz}$) while leaving booming bass frequencies ($<200\text{ Hz}$) untouched. Professional acoustic design aims for 15% to 25% total surface coverage with thick (4-inch) broadband absorbers to achieve a balanced, flat frequency decay time.

Frequently Asked Questions

What is a Sabin?

A Sabin is a unit of sound absorption named after acoustic pioneer Wallace Clement Sabine. One square foot of 100% sound-absorbing material (such as an open window where sound escapes completely) equals exactly 1.0 Sabin.

Can NRC (Noise Reduction Coefficient) exceed 1.0?

Yes! Standard ASTM laboratory tests measure absorption per square foot of front face area. Thick acoustic panels (3" to 4") mounted with an air gap absorb sound through their sides as well as the front face, yielding measured NRC ratings between 1.05 and 1.20.

What is the difference between soundproofing and acoustic treatment?

Acoustic treatment (RT60 control) controls reflections, echo, and reverberation inside the room so recordings and monitors sound clear. Soundproofing (STC isolation) blocks sound from entering or escaping the room using dense structural mass, decoupling, and airtight door seals.