Originally Posted by Adhoc1
I came across a link on a Swedish forum from poster Grahnbarr which should be of interest: https://users.aalto.fi/~ktlokki/Publs/p62_2018.pdf
In short; lesser open area percentage will mean more reflection of mids and treble (usually = positive) while at the same time increase of low frequency absorbtion (usually = positive). Decreased open area has more significance than insulation behind slats, within "reasonable thicknesses". Note: Going on the pictures from the test measurements, these are from a closed boxed
filled with absorbtion and with slats on top. Personally, I would go for open area lower than 18%, around 5-10% or so, to avoid too much absorbtion of lower mids and above.
Very useful. After doing and continuing to do extensive acoustic treatment research while building three or four types currently. I never came across those pages. There are 1001 great looking designs out there, but dimensions for many are illusive.
For instance some of the dual purpose diffusion /absorption and 90 degree bass traps at gika are a cinch to build. If I could only get precise spec paper to work from
I'm familiar with the calculators but I don't posses mics or sound analyzing equipment for testing. Already tried and tested / proven would offer some peace of mind.