What makes a curtain acoustic?
A curtain is the one acoustic surface in a room that moves. It can be drawn across glass, pulled back to the light, or hung inside the space to soften a corner, and its folds add their own light and shadow to a woven relief. Getzner makes its own acoustic curtains in Accentric Crash, with its organic texture, and Optic Structure, with its three-dimensional surface and, at 702 g/m², the heaviest Optic fabric. For the quiet room at Kindergarten Bludenz-Mitte, Getzner lists an acunic curtain and an acunic frame in Optic Structure.
An acoustic curtain absorbs sound inside the room and shortens reverberation. Three things decide how much: the fabric, how much fabric is gathered into the curtain, and how far it hangs from the wall or glass. Flow resistance belongs to the fabric; absorption in use depends on it and on the construction behind it, which for a curtain means its fullness and its air gap. ASTM E795, the laboratory practice for mounting absorption test specimens, states the general rule for a material covering a surface: its absorption depends on its physical properties and on the way it is mounted.
How much fullness does an acoustic curtain need?
Getzner's curtain ratings were measured with 100 per cent additional fabric, so the fabric was twice the width the curtain covered. A curtain that covers 3 m of wall in that arrangement uses 6 m of fabric width before seams and hems.
How far from the wall or glass should it hang?
In Getzner's curtain measurement, Type G-150, the curtain hung at a median 150 mm from the wall, without a sealed frame. The distance is given as a median because the folds of a gathered curtain sit nearer to and further from the wall along its length. The track position sets this gap, so a curtain hung with its median 150 mm from the wall is the arrangement the rating describes.
Which Acunic fabrics are measured as curtains?
Getzner's datasheets of 14 March 2024 give curtain ratings for many Acunic fabrics, measured to DIN EN ISO 354 and rated to DIN EN ISO 11654. The table lists each Acunic absorption figure under the mounting it was measured in; the Type G-150 row is the curtain measurement.
Getzner datasheet absorption, by mounting
Within the curtain row, Optic Structure rates highest at αw 0.90, class A, as a gathered curtain with 100 per cent extra fabric at a median 150 mm from the wall (Type G-150, DIN EN ISO 354 and DIN EN ISO 11654, Getzner datasheet of 14 March 2024). Volumic Weave rates αw 0.85 (H), class B, and Basic αw 0.85, class B, in the same Type G-150 curtain mounting, on the same standards and datasheet date.
The Type E-150 fabrics were measured stretched across a sealed frame at 150 mm clearance, so their figures describe framed panels. Every curtain figure here is Getzner's own, from its datasheets of 14 March 2024. To read αw and its classes, see how NRC, αw and absorption class work.
Getzner's datasheets say technical specifications may differ for dyed fabric, so a dyed curtain's performance is confirmed for each order.
Do acoustic curtains block noise?
A curtain works on the sound already in the room, which it absorbs. Keeping traffic noise out at the window, and voices from passing to the next room, is the work of sound insulation. The Australian Building Codes Board's sound handbook describes sound insulation as a building element's ability to limit sound passing through it, improved by added mass, extra skins with a cavity, limp materials and damping. That is the job of the wall and the window, and the difference between absorption and insulation is set out separately.
What happens when the curtain is open?
A rating describes the curtain drawn across its full width. Drawn back, the same fabric gathers into a stack beside the opening and the glass faces the room again, so one curtain lets a room move between a calmer and a livelier sound. Where a room needs the absorption while it is in use, such as a restaurant during evening service, plan where the curtain stacks and when it will be drawn. The fabric choices for restaurants and bars show how curtains fit with sails and panels.
Which finished curtain systems does Getzner make?
Getzner makes the acunic curtain and the acunic area. The acunic curtain is made to measure and supplied with its rail, for use at the window or within the space, in 1400, 2000 and 2600 mm widths at 2500 mm high. The acunic area is a panel curtain for large surfaces, on an anodised aluminium rail fixed directly to the ceiling or suspended, intended for event spaces and public areas, 1700 mm wide in three heights and with a design angle option. The Acunic curtains page shows both systems and the fabrics Getzner makes them in.
For care, the curtain fabrics take a 40 °C delicates cycle, according to their datasheets; cleaning each Acunic fabric covers the rest.
Do acoustic curtains need to be fire rated?
In most buildings, no. NCC C2D11(3) exempts "a curtain, blind, or similar decor, other than a proscenium curtain required by Specification 32" from the fire hazard property requirements, and the exemption has the same number and the same words in NCC 2022 and NCC 2025, so it applies whichever edition your state uses.
New South Wales adds an exception. In the public parts of a Class 9b entertainment venue, the NSW version of Specification 7 sets a Flammability Index of not more than 6 for a curtain, blind or similar decor, tested to AS 1530.2. For a curtain in those spaces, ask AKA Acoustics before specifying. The exemption, its exceptions and New Zealand's rules are explained in whether curtains need to be fire rated.
