Cinema / Theatre Acoustic Design Guide
Cinemas and theatres require short reverberation times (0.8–1.2 seconds) to preserve dialogue clarity and allow the soundtrack’s engineered reverberation to be heard accurately. Background noise must ...
Requirements by Standard
The table below shows acoustic requirements for cinema / theatre spaces across 4 applicable standards. Values are sourced from published standards documents.
| Standard | RT60 | Noise | STI | Notes |
|---|---|---|---|---|
| UnitedBS 8233:2014 | — | — | — | — |
| InternationalWELL v2 Feature S01 (Sound) | — | — | — | — |
| InternationalISO 3382-1:2009 | 0.8–1.2s | — | — | Informative, for speech-dominant theatres |
| AustraliaNCC 2022 / AS/NZS 2107:2016 | ≤0.8s | LAeq 30 | — | Unoccupied |
Recommended Acoustic Treatment
Material specifications for achieving compliance in a typical cinema / theatre. All NRC values reference ISO 354:2003 test data.
| Surface | Material Category | Min NRC | Coverage % |
|---|---|---|---|
| Side walls | Fabric-wrapped panels | 0.85 | 60% |
| Rear wall | Deep absorptive treatment | 0.90 | 80% |
| Ceiling (rear) | Acoustic ceiling tiles | 0.80 | 50% |
| Seating | Upholstered tip-up seats | 0.75 | 100% |
Browse the acoustic materials database for specific product absorption coefficients.
Common Design Mistakes
HVAC noise from projection room and plant
Cinema HVAC systems must remove significant heat loads from projectors and amplifiers while maintaining NC-25 in the auditorium. Transfer paths through the projection window, ductwork, and shared structural elements frequently compromise the noise floor. Dedicated AHUs with acoustic lagging and oversized ductwork are required.
Excessive reverberation masking dialogue
Theatres with RT60 above 1.5 seconds suffer from poor dialogue clarity, as room reflections overlap with the next spoken word. Unlike concert halls where reverb enhances music, cinema and theatre rely on the acoustic designer and sound engineer to create the desired ambience. The room itself should be acoustically neutral.
Bass frequency cross-talk between auditoriums
Low frequencies (below 125 Hz) in modern cinema soundtracks can reach 115 dB SPL. Standard STC 50 partitions provide only 20–25 dB attenuation at 63 Hz, meaning bass from an adjacent screening is clearly audible. STC 65+ with specific low-frequency performance (double-leaf masonry with 100 mm air gap minimum) is required.
Flutter echo from parallel rear wall and proscenium
The parallel relationship between the rear auditorium wall and the proscenium/screen wall creates flutter echo that colours dialogue and music. The rear wall must be heavily absorptive (NRC ≥0.80) or angled to redirect reflections away from the audience.
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Frequently Asked Questions
What RT60 should a cinema or theatre achieve?
Per ISO 3382-1:2009 and THX/Dolby design standards, cinema auditoriums should achieve RT60 of 0.3–0.5 seconds for immersive surround-sound presentations, while drama theatres should target 0.8–1.2 seconds for natural speech projection. Musical theatres with combined speech and music target 1.0–1.2 seconds. The shorter cinema RT60 ensures the electronically produced soundtrack reverberation is not masked by room reflections.
What background noise level should a cinema achieve?
Per THX certification requirements, cinema auditoriums must achieve NC-25 (approximately 30 dBA) with all mechanical systems operating. No individual octave band may exceed the NC curve by more than 3 dB. Dolby Atmos certification has similar requirements. This demands dedicated AHUs with acoustic lagging, oversized ductwork at 3–4 m/s face velocity, and spring-isolated plant on floating slabs.
What STC is required between cinema auditoriums?
Per THX certification, adjacent auditoriums require STC 65+ with additional low-frequency performance criteria below 125 Hz. Standard STC ratings do not adequately characterise low-frequency performance, so cinema designers specify additional transmission loss requirements at 63 Hz and 125 Hz octave bands. This typically requires double-leaf masonry or concrete construction with 100–200 mm air gaps and independent structural frames.
How does cinema acoustic design differ from concert halls?
Per ISO 3382-1:2009, concert halls aim for long RT60 (1.8–2.2s) because natural room reverberation enhances live music. Cinemas aim for short RT60 (0.3–0.5s) because the soundtrack already contains engineered reverberation. Concert halls use reflective, diffusive surfaces; cinemas use absorptive surfaces. Concert halls value lateral reflections; cinemas must suppress them to preserve surround-sound spatial cues from the speaker system.