Ideal thickness for corner traps

[Getafix]

Hi guys,

So at the moment i have 4 inch rockwool (50kg/m3) on all the corners of my room. I'm still not happy with the sound in the room as it can get a bit boomy on high levels.

The room is around 13 feet x 9 feet with a 9 foot ceiling. I just found a company that can sell me semi-rigid rockwool panels that have a density of 110kg/m3 & are 4 inch thick.

So my question is if i use this rockwool in the corners instead of the less dense panels i have up right now, will there be an improvement in the low end absorption?

If not, i was thinking of combining one 4 inch panel that is 100Kg/m3 with another 2 inch panel that is 50kg/m3 to get a 6 inch thick panel for the corners.

If a 4 inch 100kg/m3 panel on it's own is enough then i can use the remaining panels to treat other areas of the room, such as the front & backwall as well as the reflection points.

So i would like to know which setup would be the best. Thanks.

[bpape]

By the time you have enough material to do 6" thick, the same amount will make solid 17x17x24" triangular chunks that are about 12" thick in the middle.

Also, don't forget that some of the bass issues are not purely in the vertical corners of the room. You may be getting overlap in modes from 2 axial dimensions so treatment on some of the walls may be beneficial.

Lastly, don't ignore the wall/ceiling horizontal corners of the room.

Bryan

[Getafix]

Thanks for the reply Bryan. I know that superchunks will probably give me the best bang for the buck but i'm probably going to be changing rooms in another month. So i prefer to have panels as it will be easier to move around between rooms.

So if i understood your answer correctly, the corners of the room should be alright & i should concentrate on the horizontal corners of the room instead?

I was walking around the room to see where the bass was building up & the corners were mostly fine. Just the spot right in front of my mixing position behind the speakers was a bit bassy, where i currently only have 2 inch panels hanging. So i think i'm going to double the thickness of those panels & concentrate of the horizontal corners as you recommended.

[wesarvin]

I used a frame for my corner chunks. They are basically 4 ft tall triangular solids. They're freestanding (like GIK's Tri-Corners). I even hung a leftover one on the wall-ceiling corner in front of the mix position using L-brackets and butterfly bolts. Even though they're not made of 703 (just two layers of R-30), they've helped tremendously in the response of the room.

[bpape]

I didn't say concentrate in the horizontal corners, I just said don't forget them.

If your main problems were behind/beside the speakers, that's an SBIR issue. How thick to treat them properly would require you to measure the response and see where you have issues. Treat only as low frequency wise as you have to to avoid causing more issues down lower potentially.

Bryan

[wesarvin]

Umm, forgive me for butting in, but doesn't this thinking negate Ethan's "you can't have too many bass traps?"

[Getafix]

Yeah i was gonna ask the same question.

On another note, i just downloaded this file to check the response in my room & the results were quite alarming!

Room For Improvement: Audio file

The volume bumped up in a couple of spots by quite large amounts. So i guess 12 traps are just not enough for my room & i need to do a lot more treatment.

[avare]

The boom is around low B and D. This the width and height f the room being almost identical. If you don't want to do what is needed because you are moving shortly, I suggest you live with it for a month. What the room needs tuned absorbers, either panel traps or Helmholtz absorbers.

What is the wall and ceiling construction? What materials are they made from?

Andre

[Getafix]

Yeah there were two points where the volume bumped up, once around 12-13 seconds into the file & then again towards the end around 21-23 seconds.

The wall construction is just plain brick with plaster & wallpaper on top. The ceiling is concrete & there's a thick carpet on the floor.

[avare]

Thanks for the construction details. Unfortunately those surfaces reflect lows very well. You would need very large amounts of absorption to get a noticeable improvement. Incidentally, as you make filled absorbers thicker, lighter material is better.

Best to give information on your new space so you can set that up the best possible right away.


Andre

[bpape]

I didn't say don't treat broadband. I said strictly for SBIR issues, treat only as low as you need to so you avoid creating other potential problems that you didn't have before.

Bryan