[klh]

To any and all...

I have the materials ready to finish my room treatments. Before I start the fabrication process, I have some concerns.

Here is what I have planned:

For the horizonatal cross corner traps I have 2" 703 equivalient rigid fiberglass with FSK that will essentially form a 1' wide ring around the room. I know it would work better if it were 2' wide but this was done for aesthetics and decreased weight.

For the vertical cross corner traps I have 2' wide unfaced 6" deep 8# mineral wool that will run floor to ceiling.

For all points of first reflection, I have unfaced 2" 703 equivalent that will be spaced 2" off the wall.

My room is 16'x20'x9', has wall to wall carpet, single layer sheetrock and the studs are 16" OC for the walls, 24" OC for the ceiling. Lastly, there is about 57 cubic feet of windows.

The points of first reflection will be easy to build. My concern is regarding building the cross corner traps.... for the traps that have the foil, does the fabric need to be applied in such a way that the fabric doesn't actually touch the foil? If so, what are your suggestions on how to do that? Also, do you think I should purchase foil and adhere it to the currently unfaced vertical traps? If so, how would you adhere it to the mineral wool?

I understand that foil skews the absorptive capability of the traps (boosts absorption in the mid 200 Hz range)... given the dimensions of the room, do you think that would be desirable?

Please post your ideas and recommendations.

[Ethan Winer]

Krister,

> For the horizonatal cross corner traps I have 2" 703 equivalient rigid fiberglass with FSK <

It would be a lot better if they were four inches thick, though that's a different issue.

> does the fabric need to be applied in such a way that the fabric doesn't actually touch the foil? <

Nope. Just glue it on (or don't) and it will be fine.

--Ethan

[klh]

Great!

Yeah, 4" thick would be nice, but the OC 703 equivalent comes in 80 sq ft batches and 10 additional panels would be overkill!

Does anyone near Sacramento want to go in on a batch?

[Ethan Winer]

> Yeah, 4" thick would be nice, but the OC 703 equivalent comes in 80 sq ft batches and 10 additional panels would be overkill! <

So make them 6 inches thick. You're worried about a relatively small outlay when the potential to make your room a lot better hangs in the balance?

--Ethan

[klh]

  OK OK 

[klh]

Ethan... I've done some math and I can make full use of the 10 panels without deadening the room too much. I keep the faced 12" wide rigid fiberglass for the wall/ceiling corners as already planned. I have already cut the framework... and it was a royal PIA... so I don't want to change that. I can, however, put 12" wide unfaced OC 703 equivalent behind it that is tapered to 8" (so a 2" taper on each side). I would then put a 3rd layer that is 8" wide and is tapered to 4" wide. Basically I would be filling the gap behind the trap. This defintely would help with absorption. My interpretation of your post was you want me to put a 12" wide unfaced peice where the current one is to go and put the faced 12" one over the unfaced one (with the foil on the exposed side). This would effectively push the trap further out from the corner and thus increase the low end absorptive capablity of the trap (both in to lower frequencies as well as increased efficiency). My idea at the beginning of this post probably wouldn't extend the lower frequency absorption too much, if at all, but would increase the amount of absorption for the frequencies already absorbed. Am I right? What do you think of my plan?

[Ethan Winer]

Krister,

> What do you think of my plan? <

As long as the faced panels are on the outside (or inside) only, and not used for the in-between layers, you'll be fine.

--Ethan

[Glenn K]

Krister,

> What do you think of my plan? <

As long as the faced panels are on the outside (or inside) only, and not used for the in-between layers, you'll be fine.

--Ethan

Ethan I have never tried that (maybe I miss understood you).. Facing on the back of the panel??

Glenn

[klh]

I think he means the panels can be stacked as thick as I want but there should only be one foil layer and it should face into the room.

[klh]

Well, I finished painting the walls so I finally put the fabric on the vertical bass traps as well as the bass trap behind the seated position. I'm very happy with how they look. Not perfect, but close enough. As of now they don't have foil over over the front. I didn't use adhesive spray and the cloth is only held on by staples so making changes will be relativel easy if I decide to do it. Now I'm on to the the first reflection points and the horizontal cross corner traps. I'm taking a bit of a break since the rest of the treatments will all use rigid fiberglass. Unfortunately most of the remaining units require cutting the fiberglass so I'm preparing myself to itch .

[Glenn K]

I think he means the panels can be stacked as thick as I want but there should only be one foil layer and it should face into the room.

I am sure that is what he meant.

Glenn

[klh]

What is the best way to cut 2" 3# rigid fiberglass?

[Glenn K]

A long knife will work fine. Wear gloves, long shirt, hat and glasses. 

Glenn

[klh]

Hopefully I'll get a chance to do it this weekend (the in-laws are in town). I'm cringing already... about cutting the fiberglass of course!

[klh]

Well, progress has been made. I cut the fiberglass, used the 3M adhesive and put 'em in place. It looks beautiful. There are 1st point absorbers on the side walls (2 panels each), the front wall (three 1 panel absorbers) and on the ceiling (4 panels). These are all in addition to the back bass trap and the vertical bass traps. I'm still waiting to do the horizontal traps... I haven't had the chance to get the fiberglass for the horizontal bass traps.