absorb low frequency sound
short bass reverb is crucial for rock
absorb evenly from 63 Hz to 1kHz
the fundamental frequencies of music
audiences absorb higher frequencies
high Q directs HF at audience
“When I first started conceptualising how to create variable acoustics that would work well at low frequencies I turned towards membrane absorption.
There is a paper in the research section, which explains the physics of membrane absorbers. Basically, due to a sound pressure difference on the inside and the outside, the membrane will vibrate. Think of for instance how windows rattle when there is loud music in a room or loud noise outside. Opening the window to a degree where the sound pressure is the same on both sides, one will witness that vibrations stop (given that it is not multi-layer glazing).
Many years earlier, the father of a talented drum-student of mine, a clever engineer, had mentioned, that if one wanted to adjust something mechanically one could consider compressed air.
My first concepts therefore comprised of a hard shell with a soft membrane in front. Air was to be sucked out to nullify the cavity inside and thereby any membrane absorption. Inversely, air could be supplied to create a cavity.
But as it turned out, small cavities were hard to avoid resulting simply in membrane absorbers with a higher resonance frequency rather than completely avoiding any absorption.
I realized, that completely omitting a hard shell could be one way to proceed and that this would leave me simply with inflated membranes embodied in for instance an air-mattress, which is in fact a membrane absorber!
Many prototypes were built over a number of years until getting to a product that actually worked well acoustically and at the same time complied with international safety- and fire regulations. The final result not only absorbs low frequencies, but covers the entire need for variable absorption, still leaving the high frequencies fairly undamped, which is a blessing even for amplified music. The technology is patented.
It is my sincere hope, and that of the investors behind Flex Acoustics, that my work will result in even better concerts, more joy for everyone involved, regardless the genre of music.”