Room Acoustics

What is room acoustics?

Room acoustics is the design discipline that controls the reflection, absorption and diffusion of sound waves inside a space. Speech intelligibility, music quality, privacy and focus are calculated together. In an unaddressed conference room, reverberation can exceed 2 seconds, causing speech to overlap.

Where is it applied?

• Recording studios and karaoke rooms
• Cinemas and home theatres
• Conference, meeting and seminar rooms
• Telepresence / podcast studios
• Office acoustic treatment
• Theatres, opera houses and concert halls
• Discos, bars and clubs
• Restaurants, cafés and hotel lobbies
• Call centres
• Schools and lecture halls
• Sports / fitness facilities

Which parameters are measured?

• RT60 (reverberation time): time for sound to decay by 60 dB. Studio 0.3-0.4 s, office 0.5-0.7 s, church/concert 1.5-2.0 s.
• STI (speech transmission index): 0-1 scale. Above 0.60 = "good", above 0.75 = "excellent".
• NC (noise criterion): background noise level. Studio NC 20, office NC 35, restaurant NC 40 ideal.

Which materials and systems do we use?

• Acoustic panels: fabric-wrapped, wood, felt, melamine (Basotect) — for broadband absorption
• Baffles and cloud panels: high NRC with air gap in tall spaces
• Diffuser panels: scatter sound waves to break echo (critical in studios)
• Bass traps: low-frequency absorption (50-200 Hz)
• Sound masking: controlled pink noise for open-office privacy

How is design carried out?

1. Geometry, volume and surface areas are calculated.
2. Existing RT60 is measured or computed.
3. Required absorption coefficient is calculated to reach target RT60 (Sabine formula).
4. Simulation is run with ODEON, EASE or INSUL.
5. Panel types, quantities and locations are specified.
6. Final measurement verifies the target parameter.

The ABC method for office acoustics

For open-plan offices the internationally accepted ABC method applies: Absorb (add absorptive panels to surfaces), Block (partitions/booths between workstations), Cover (mask with sound masking).

Time and cost

A single room takes 2-5 days, a mid-sized office or conference hall 1-2 weeks, a professional recording studio 3-6 weeks. Investment is per square metre but is typically recovered in the first year through productivity, sound quality and satisfaction.