Interior · HUB · REV 2026-10-06
Hall interiors
The visible surface is an acoustic decision. Solid wood reflects in the speech range. Perforated wood with a cavity and an absorber, or PET felt at the tested thickness and mounting, absorbs in a band set by the test, not by the photograph.
What this gate is
The gate covers theatre interiors, wall cladding, and acoustic ceilings. The interior serves acoustics, sightlines, maintenance access, and light. Cladding may reflect or absorb depending on what is behind it. A cloud or a baffle leaves services open. A mineral tile in a theatre is a choice with consequences for RT60.
Hatching on a drawing is not a reverberation time. An absorption coefficient comes from an ISO 354 report for a named mounting, with its frequencies. This gate publishes no product coefficient and no fire class. Fire comes from the report of the build-up: face, adhesive, core, and substrate.
What is published now
Theatre interiors
Surfaces that serve sound, sightline, and lighting access, not a finish schedule pasted on the hall.
Wall cladding
Wood or fabric that reflects or absorbs according to the cavity and the material behind. Perforation alone is not enough. Fire and impact count.
Acoustic ceilings
Clouds, baffles, a black ceiling over the stage, and services coordination. A mineral tile is a choice with acoustic consequences.
PET felt
A common porous face. Its absorption comes from the report of mounting, thickness, and cavity, not from the material name.
When to open this gate
Before the material board is signed
While the cavity, the absorber, and the hard surface can still be named. After installation, change is demolition.
When services fight the ceiling
Ducts, sprinklers, loudspeakers, and rigging points. An acoustic ceiling is not drawn after the soffit is already full.
When fabric or wood colour changes
A substitution can keep the look and change both fire and absorption. The report has to be tied to the new build-up again.
How to read the subject
- 01
Classify every surface: early reflector, absorber, diffuser, or a visual cover with no acoustic role. An unclassified surface does not enter the calculation.
- 02
Write what is behind the face: cavity in millimetres, the porous layer, and open area if there is perforation. The photograph does not carry those data.
- 03
Coordinate the sightline: a balcony front, a rail, and a side wall can block the last row or the useful reflection.
- 04
Leave a maintenance path: how a panel comes off without destroying the absorber, and how a lamp is replaced without closing the hall for a week.
What this gate does not do
A finish schedule instead of a specification
A wood name and a fabric colour with no cavity, no absorber, and no fire report. That is decor, not a hall interior.
Perforation with no absorber
Holes on a hard surface are a texture. Absorption needs a cavity and a porous material named in the report.
A black ceiling assumed to absorb
Colour hides the fly tower visually. A hard black soffit reflects. Absorption is a property of the build-up, not of the paint.
Questions designers and owners ask
Does PET felt absorb bass?
A thin layer on a hard wall is weak at low frequency. Low frequency needs thickness or a spacing off the surface. The coefficient comes from an ISO 354 report, not from the name.
Is a mineral ceiling tile right for a theatre?
It may suit speech. For unamplified music it can kill the high frequencies and leave the room without a shaped reflector. The decision is acoustic, not an office-ceiling catalogue.
Where does the fire class come from?
From the test report of the specified build-up. This gate gives neither a class nor a certificate.
Is an early reflection a mistake?
Not in a speech or music room that wants lateral support. The mistake is putting absorber where a useful reflector belongs, or a late echo from the rear wall.
What do I read with this gate?
The treatment and RT60 pages, then the laboratory report for the build-up, then ISO 3382-1 if the verdict is a measurement.
Technical sources
- ISO 354
Reverberation-room measurement of absorption for a named mounting. The gate does not copy a coefficient from that measurement.
- ISO 3382-1
Measurement of room parameters after installation. Drawing coverage does not replace it.
- Reaction-to-fire test report
The class belongs to the tested assembly, not to the photograph. This gate does not carry the certificate.
Last editorial review: 2026-10-06. Review means the text was checked, not that a project was measured.
Turn the question into a brief
A study starts from room volume, use, and existing condition, not from a product name. Fill the brief and copy it.
Project study form