Why the air gap behind an acoustic curtain matters

01 / THE DETAIL

Keep the comparison like for like

The space between a curtain and the surface behind it changes the acoustic assembly. The table holds the fabric constant and compares the two cavity dimensions published by the manufacturer. Read across a row to keep fullness constant too.

The 100 mm and 350 mm figures are test conditions, not universal fitting instructions. They help you ask whether the proposed curtain position resembles the evidence used to select Wool Serge 800.

02 / THE DETAIL

A deeper position uses real floor space

Moving a track away from the wall affects more than a drawing. Check door swings, furniture, radiators, window handles and the route people use past the closed curtain. Confirm the projection of ceiling or wall brackets and allow for the depth of the folds.

Our mounting guide explains the options. On a plan, mark the wall, the curtain position and the usable room area after installation. This makes a proposed cavity easier to review with the installer.

03 / THE DETAIL

Do not interpolate a new acoustic promise

A 225 mm gap is not automatically halfway between two published ratings. Nor can you combine the best rating from one fullness with a different hanging condition. If the available space does not match a documented configuration, describe the difference and request suitable evidence.

For an estimate using frequency data, the same discipline applies: use the coefficient for the actual reported arrangement. See our explanation of frequency response.

04 / THE DETAIL

Record the final arrangement

Include the intended wall spacing in your project notes, together with fabric, fullness, lining and operating position. A curtain that is usually stacked to one side does not cover the same area as the closed curtain. If an acoustic target is important, review the proposed assembly and room with an acoustic specialist before treating the published table as a design solution.