Hipper
Addicted to Fun and Learning
From the pictures it looks like the corner bass traps are closed boxes, all I see is wood. Where's the opening of the boxes pointing to, the side showing the Isobond on the other picture?
Corner bass traps should be open to all sides facing the room.
they are mostly closed, yes. I built those when i had no idea and seems like i still have no idea as i was not aware (until now) that bass traps should be open on all sides facing the room
i could move them so the open side faces the room and do a measure - do you think that makes a big difference?
I also noticed that the bass traps appeared to covered with wood of sorts. The bass traps I have, bought from GIK, are covered in a sonically transparent cloth. You can buy this cloth from GIK and I would guess other places.
https://gikacoustics.co.uk/product/gik-acoustics-soffit-bass-trap/
I have the original Soffit Bass Traps with no additional pieces. They are made of a simple wooden frame containing mineral wool and covered in fabric The fabric is not only used for being porous to sound but also to protect the user from the irritation of mineral wool. Only the top and bottom have a thin piece of plywood to cover (also covered in fabric but only for appearance's sake). I don't know how mineral wool compares to your Caruso-Iso-Bond.
If you put porous fabric all around your bass traps you might also benefit from the space between the trap and your wall.
Even when you use lots of big bass traps (I have 21 GIK Soffit Traps) there will still be bass anomalies that require DSP/EQ or subwoofers (or both) to improve. I use a Behringer DEQ2496 digital equaliser (only two channel though so no good for your home theatre purposes).