Room acoustics guides
Fundamentals, selection help and planning knowledge on sound absorbers, reverberation time and acoustic metrics. Clearly explained, backed by real measurement data.
Sound absorption coefficient database
What the database contains, where its 4,373 measurements come from, how they are measured, plus a table of 30 materials from the PTB measurements.
Sound absorption coefficient αw: what counts as a good value?
Class A starts at αw 0.90, class E at 0.15. What separates αs, αp and αw under ISO 354 and ISO 11654, and why the single number alone is never enough.
Sound absorption classes A to E: table and meaning
The sound absorption classes to ISO 11654: table with the αw limits of classes A to E, what class A saves in practice compared with class C, and when which class is enough.
Reverberation room measurement to ISO 354: procedure, specimen, cost
How a reverberation room measurement to ISO 354 works: room, specimen, reverberation times, calculation of αs, αw and absorption class, test report. Cost: EUR 590 per measurement via Acoustic Index.
Comparing sound absorbers: what really matters
Comparing sound absorbers: why a single αw figure misleads, how the air gap and the test method shift the values, and which material class suits which job. With a comparison table and real ISO measured data.
Basotect vs stone wool: absorption, bass, fire safety
Basotect vs stone wool compared head to head: absorption coefficient per thickness, flow resistivity, fire class and the crossover frequency below which stone wool wins in the bass.
Acoustic foam or mineral wool: the acoustic comparison
Acoustic foam (melamine/PU) or mineral wool? An honest comparison by fire class, low-frequency performance, hygiene, weight and cost, with a decision matrix per use case.
Sound insulation vs. sound absorption: the difference explained
Sound insulation (R'w in dB) separates rooms, sound absorption (αw) reduces reverberation within a room. Why a wall absorber does practically nothing for insulation, with figures.
RT60 & Reverberation Time Calculator
Free RT60 calculator with Sabine and Eyring. Enter room size and surfaces, get the reverberation time and the absorber area you still need in m².