Worked Example: Recording Studio Control Room — EBU Standard
80 m³ control room with mineral wool ceiling, acoustic foam, QRD diffusers, and fabric panels
A 80 m³ recording studio designed to ISO-3382 requires RT60 ≤ 0.3s. With Mineral wool 50mm (wall) on the ceiling and Acoustic foam 50mm on walls, the calculated RT60 is 0.24s — PASS.
Room Setup
Total surface area: 97.6 m². Calculation method: Sabine equation (ISO 3382-2:2008 Annex A).
Surface Materials
| Surface | Material | Area (m²) | NRC |
|---|---|---|---|
| Ceiling — mineral wool | Mineral wool 50mm (wall) | 20.0 | 0.73 |
| Floor | Heavy carpet | 20.0 | 0.29 |
| Front wall — acoustic foam | Acoustic foam 50mm | 16.0 | 0.63 |
| Rear wall — QRD diffuser | QRD diffuser (wooden) | 16.0 | 0.14 |
| Side walls — fabric panels | Fabric-wrapped panel 50mm | 20.0 | 0.78 |
| Console window | Double glazing 6mm | 4.0 | 0.03 |
| Door | Solid timber door | 1.6 | 0.09 |
Absorption coefficients sourced from manufacturer datasheets and ISO 354 test reports. Browse the full acoustic materials database.
Step-by-Step Calculation
- 1
Room Volume
V = L × W × H = 5 × 4 × 4 = 80 m³
- 2
Total Surface Area
Stotal = 20.0 + 20.0 + 16.0 + 16.0 + 20.0 + 4.0 + 1.6 = 97.6 m²
- 3
Absorption per Surface at 500 Hz
Ceiling — mineral wool: 20.0 m² × 0.70 = 14.00 Sabins
Floor: 20.0 m² × 0.14 = 2.80 Sabins
Front wall — acoustic foam: 16.0 m² × 0.55 = 8.80 Sabins
Rear wall — QRD diffuser: 16.0 m² × 0.15 = 2.40 Sabins
Side walls — fabric panels: 20.0 m² × 0.78 = 15.60 Sabins
Console window: 4.0 m² × 0.04 = 0.16 Sabins
Door: 1.6 m² × 0.08 = 0.13 Sabins
- 4
Total Absorption at 500 Hz
Atotal = 14.00 + 2.80 + 8.80 + 2.40 + 15.60 + 0.16 + 0.13 = 43.89 Sabins
- 5
Sabine RT60 at 500 Hz
RT60 = 0.161 × V / A = 0.161 × 80 / 43.89 = 0.29s
- 6
Compare to Target
Mid-frequency RT60 (avg of 500, 1k, 2k Hz) = 0.24s. Target: 0.2--0.3s per ISO-3382. Verdict: PASS
Octave Band Results
| Frequency | 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz |
|---|---|---|---|---|---|---|
| Total Absorption (Sabins) | 10.9 | 29.8 | 43.9 | 56.0 | 64.2 | 65.0 |
| RT60 (s) | 1.18 | 0.43 | 0.29 | 0.23 | 0.20 | 0.20 |
| Target (s) | — | — | 0.30 | 0.30 | 0.30 | — |
| Verdict | — | — | PASS | PASS | PASS | — |
Compliance Verdict
Reference:
Open the AcousPlan calculator pre-loaded with the exact room dimensions (5m × 4m × 4m) and RT60 target (0.3s).
Open CalculatorField Story
A Grammy-winning mixing engineer is building a personal control room in a converted Nashville warehouse. The 5 m by 4 m room with generous 4 m ceiling height follows EBU Tech 3276 recommendations for critical listening. The front wall behind the monitors is covered in 50 mm acoustic foam eliminating speaker-boundary interference response (SBIR) causing comb filtering. The rear wall features QRD wooden diffusers that scatter reflections without absorbing them, maintaining liveliness while preventing flutter echo. Mineral wool ceiling panels and fabric-wrapped side wall panels provide broadband absorption. The 4 m² console window into the live room uses laminated double glazing for isolation and minimal reflection. The EBU target of 0.3 s or below ensures the engineer hears the recording, not the room.
Frequently Asked Questions
What RT60 does a Recording Studio Control Room — EBU Standard achieve?
With the specified materials and dimensions (5m x 4m x 4m, volume 80m3), the calculated mid-frequency RT60 is 0.24s using the Sabine equation. The target under ISO-3382 is 0.2--0.3s. The result is a PASS.
What materials are used in this performance acoustic example?
This example uses Mineral wool 50mm (wall) on the Ceiling — mineral wool (NRC 0.73), Heavy carpet on the Floor (NRC 0.29), Acoustic foam 50mm on the Front wall — acoustic foam (NRC 0.63), QRD diffuser (wooden) on the Rear wall — QRD diffuser (NRC 0.14), Fabric-wrapped panel 50mm on the Side walls — fabric panels (NRC 0.78), Double glazing 6mm on the Console window (NRC 0.03), Solid timber door on the Door (NRC 0.09). The total absorption at 500 Hz is 43.9 Sabins.
How much does acoustic treatment cost for this room?
Cost data is not available for this example. Use the AcousPlan calculator to estimate treatment costs for your specific room configuration.
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All calculations are advisory and based on the Sabine equation (ISO 3382-2:2008 Annex A). Results require professional verification for compliance submissions. Absorption coefficients are sourced from manufacturer datasheets and ISO 354 test reports.