Dear Ethan,
Thank You for reading this mail.
I plan to make a moovable apsorber h: 80 x w: 80 x d:40 cm - in a wood frame.

Open cell foam front panel, with rockwool sandwiched inside - between, and a foam panel at the back again.

There willl be 80x80x10 cm foam panel at the front.
I will make a narrow foam frame on the sides of the front panel (and glue them on the edges of the base foam panel)
Then add high density rockwool - 60x60x20cm - inside the frame.
Since they only make rockwool 5 cm thick, I will add 4 layers.

Foam panel will then be added at the back. 80x80x10cm.

All will be framed in 40 cm deep and 1 cm thick wood frame - surrounding the sides only (front and back free.)

Small guitar combo wheels added at the bottom, so it can be mooved - from studio to control room.

My question is:
How low can it go?
Will it be effective down to 100Hz or.... less/more.
I plan to make two.

All the best.
Marc.

40 cm is about 16 inches thick, and that will definitely absorb to below 100 Hz. What is your intent with this absorber? In corners as bass traps they'll work very well, though you'll need more than two of them to treat a room. But if you plan to use them as gobos, this may be overkill because you can get adequate blocking with 1/4 that thickness.

--Ethan

Thanks Ethan
Control room is w: 350 x l:405cm.
Sloped ceiling - 350cm front height and 250cm rear.
I have 2 of them already - similar depth - at the front wall.
( h: 120 w: 80 d:30. Foam 20 cm and 10 cm rockwool sandwiched )
Diagonal to the corners of the front and side walls.
Plan is to add those 2 as addition, to the rear wall, and experiment mooving them arround.
Also moove them outm, and use in studio - while recording drums and double bass..
What do You think ?
Best

Sounds like a plan. More bass traps can only help.

--Ethan

Thanks Ethan