Math or no math, that’s the question
Architecture that – unintentionally – form large diffusers
PRD’s are diffusers based on math, on Prime Roots to be exact. The calculated surface irregularity ensures that soundwaves are treated much the same way as stealth planes deal with radar waves.
Walking through Helsinki city with a mind (heart) focused on acoustics, on how to dampen noise, inevitably a structure will catch the eye. A structure that reminds of a sound-treating construction.
Many a construction of the street side, walls etc. form enormous pieces of art. Seemingly, constructed to dampen noise, however unintentionally functioning as large PRD’s.
Let me lift forward a few examples from my collection from within the city of Helsinki.
Pasila train station, towards the expo-center Messukeskus :
Not only outside is this true
Many a house holds within, famous or not famous, pieces of art. Art that works just fine as a PRD.
The art with the red background breaks the otherwise gray and dull concrete building of Leppävaara swimming hall. The art (with the white background) of Rut Bryk is called ‘City in sunshine’, (Kaupunki auringossa) made 1975, and lifts the atmosphere of the Helsinki city hall.
Intentionally architected diffusers
Not all diffusers are based on prime roots. However, the constructions are for sure intentionally architected towards noise-cancelling tasks. (the following are not located in Finland)
Plates with equally-spaced holes of a certain diameter size take care of certain frequencies, and the angled piece of surface doubles with the reflective quality of a PRD panel.
The second photo shows a wall named ‘Prosolve 370e’, a structure of_thermo-formed plastic tiles, powder-coated in photocatalytic titanium dioxide (TiO2), thereby also ecologically scrubbing the air from pollution.