How this site works out what it tells you

Every number here comes out of a model, and the model is worth knowing before you spend money on the basis of one. Nothing below is a trade secret.

Where the predicted responses come from

The bass map, the seat search and the figures in the guides are all modal summation for a rigid rectangular room: every mode up to 300 Hz is computed from the three dimensions, weighted by where the speakers and your ears sit inside each mode's shape, and summed as complex pressure. Damping comes from the decay time, because a mode that takes RT60 seconds to fall 60 dB decays at a rate that follows directly from it. When you supply no RT60 measurement, an untreated-room assumption of 0.45 s stands in.

Where the treatment quantities come from

Panel and trap counts are Sabine estimates: the absorption needed to bring your room volume and measured decay time to a target, divided by the absorption one panel provides, using published coefficients for 100 mm mineral wool. Expect them to be right to within a panel or two, which is enough to buy materials and not enough to design a studio. The placement advice is a different kind of claim: first reflection points and corner positions are mirror geometry, exact given the dimensions you enter.

Where the ratio scoring comes from

Sepmeyer, Louden and Volkmann each published room proportions that spread modes out rather than piling them up, and EBU Tech 3276 gives limits as inequalities. The score is not read off any of those charts. It counts your room's actual mode spacing, how evenly the modes fill each third-octave band, and whether any land on top of each other, so an unusual ratio that happens to work scores as well as it deserves to.

What happens to your measurement

Nothing leaves your browser. The REW text export is parsed and analysed client side, which is also why the tool is free: there is no per-report cost to recover. There is no account system anywhere in the codebase and nothing to sign in to.

Where this model stops being right

  • Rectangular rooms only. An L-shape, a sloped ceiling or a room that opens into another space breaks the mode calculation, and the predictions will be confidently wrong rather than absent.
  • Rigid walls. Real walls flex and leak, which damps low modes more than the model expects. Plasterboard on studs behaves noticeably differently from concrete.
  • Furniture is not modelled. A room full of soft furnishings decays faster than its dimensions suggest.
  • The predictions are a starting point to check against a measurement, not a substitute for taking one. Where the two disagree, the measurement is right.
  • Not affiliated with Room EQ Wizard or its author. This site reads REW's text export; it is not made by the people who make REW.