Quote: Originally Posted by Mister Fox So you put 6-8cm holes into the 12cm frame, am I getting this right? I've done the holes to make the structure lighter and to improve the total exposed surface, but after some calculation i discovered that the latter is minimal ( less than 10%...) I've also found some spots in the studio with impressive bumps in the bass range, one of them in a niche behind a pillar. With some experiments I've found the right quantity of absorbent material to be put there. Voil?*! All major issues in the bass range almost resolved with a minimal effort.