Room Acoustics Calculator

Small critical listening spaces typically target somewhere in the 0.3 to 0.5 second range, since a reverb time much longer than that starts to blur speech intelligibility and muddy recorded detail. Larger spaces like concert halls or houses of worship intentionally carry much longer RT60 values, since a lush, sustained reverb is part of what those spaces are designed to deliver.

These three figures are the first axial modes — the lowest, most audible standing-wave frequency each dimension supports on its own. A complete acoustic analysis also includes tangential modes, which involve two dimensions at once, oblique modes involving all three, and higher harmonics of every mode, all of which this simplified calculator omits in favor of the resonances most likely to be audibly problematic.

Total absorption is the surface area multiplied by the absorption coefficient, and RT60 is inversely proportional to that total absorption, so raising the coefficient — by adding acoustic panels, carpet, or curtains — shortens reverb time. Doubling the effective absorption in a room roughly halves its RT60, all else held equal.

Generally yes, if the absorption coefficient stays the same, because volume grows faster than surface area as a room gets bigger, pushing the Sabine equation's ratio of volume to absorption upward. That's why large, sparsely furnished spaces like gymnasiums and warehouses tend to sound noticeably more reverberant than a similarly finished but much smaller room.