or "Why corner traps absorb a wider spectrum of bass than flat panels"
For the engineering-minded amongst us, something useful:
Sheet material will resonate at a particular frequency depending on the relationship between the mass of the material and the distance it is spaced from a solid wall surface. This resonant frequency can be calculated by dividing 60 by the square root of the panel mass (in Kg/m?) multiplied by the distance from the wall in metres.
f=60/(mass2*distance)
Simply put, the heavier the panel and/or the deeper the air space behind, the lower the resonant frequency of absorption will be. If mineral wool is included in the cavity space behind then the frequency band over which the absorber will work will be widened
So if you have a layer that weighs 9kg per m2 (or say 150 kg on a wall 5m by 3m) then the damping frequency will be:
at 5cm - 400Hz
at 20cm - 100Hz
If it weighed 25Kg per m2, or say 400Kg on a 5m by 3m wall, then
at 5 cm - 240Hz
at 20cm - 60Hz
I'm sure it becomes fiendishly complicated when there are multiple layers, or if some of them are perforated, or if you start exploring fractions of wavelengths.
For the engineering-minded amongst us, something useful:
Sheet material will resonate at a particular frequency depending on the relationship between the mass of the material and the distance it is spaced from a solid wall surface. This resonant frequency can be calculated by dividing 60 by the square root of the panel mass (in Kg/m?) multiplied by the distance from the wall in metres.
f=60/(mass2*distance)
Simply put, the heavier the panel and/or the deeper the air space behind, the lower the resonant frequency of absorption will be. If mineral wool is included in the cavity space behind then the frequency band over which the absorber will work will be widened
So if you have a layer that weighs 9kg per m2 (or say 150 kg on a wall 5m by 3m) then the damping frequency will be:
at 5cm - 400Hz
at 20cm - 100Hz
If it weighed 25Kg per m2, or say 400Kg on a 5m by 3m wall, then
at 5 cm - 240Hz
at 20cm - 60Hz
I'm sure it becomes fiendishly complicated when there are multiple layers, or if some of them are perforated, or if you start exploring fractions of wavelengths.
