Sayers slat wall

Coming from the following threads viewtopic.php?f=1&t=14563 viewtopic.php?f=2&t=14610 I am now ready to place the three layers of drywall and seal them to complete isolation for my studio. One of my concerns is now sound treatment. I would like to go for the Slat Wall as I've read and been told it sound very nice, natural and is very effective. I have read on the subject but I still have a couple of doubts. After the drywall is in place I intend to place timber studs, fiberglas/rockwool, cloth and finally the slats. 1) Recommended Fiberglass is still 50mm thick 40kg/m2 like in isolation (50kg/m2 for rockwool) ? 2) How do I determine widths and gaps for the slats 3) Can the slats be made of MDF or plywood instead of timber? 4) Can I paint/varnish the slats? Thanks for your time and help. Sono

nobody?

Hey Sono! Looks like folks are busy with other stuff around here lately! Quick answers:

1) Recommended Fiberglass is still 50mm thick 40kg/m2 like in isolation (50kg/m2 for rockwool) ?

Yup. Anything in that ball-park should work. Don't go too dense if you are planning on dealing with lows, and don't go too light-weight if you need to deal with highs. The numbers you mentioned are a good compromise. (There is some in-depth info on that in IR-832, and also IR-693)

2) How do I determine widths and gaps for the slats

For a good, general-purpose broad-band slot wall, use the numbers that John gives on his diagrams and in his recording manual (SAE manual). OR if you have specific problem frequencies, then you can calculate the slot dimensions and cavity depth using the Helmholtz equation (but make sure you use the RIGHT one! There is a WRONG version of that equation floating around on the internet, and even published in some books, so take care that you don't get the wrong one...)

3) Can the slats be made of MDF or plywood instead of timber?

Yup. Anything fairly stiff and dense will do the job.

4) Can I paint/varnish the slats?

Yup. Jut don't put it on too thick, as that could change the characteristics of the slots. A couple of thin coats won't do any harm but if you really layer it up disgustingly thick, that might not be a good idea. - Stuart -

Stuart, Thanks for your reply. I apologize for taking a few days to get back but I have been working hard at my studio.... I never imagined sealing and caulk could be so exhausting and painful :) Anyway, so I have one layer of drywall left to place. I have been paranoically sealing every single square millimeter in each layer. Once that's done, hopefully tomorrow I will clean up thoroughly and place the studs for the acoustic treatment. But I think I have a couple problems in the way. Here is the room sketch as it is now. My problems: 1) I would like to place hangers as a bass trap on the corners in the rear wall BUT I have the impression that the door is too close to the wall to leave space for a hanger bass trap. Is that right? Any alternatives/suggestions (other than moving the door, please...) 2) I have calculated the sweet spot at 38% of the Length of the room (that's roughly 2.16m from the wall). From there I drawed a triangle with a 60º angle at the sweet spot facing the wall. At what distance from the sweet spot should I place the speakers following those 2 lines at 60º? 3) I intend to build a 12º inclination ceiling. From the center of the room at ceiling height the treatment will descend at 12º, and will be around 0.7 metres at 3m length. Is this correct? Does this need to be on both sides of the center of the room or only on the speakers' side? Thanks a lot for your help and support Cheers

Drywall is FINISHED :yahoo: Back to Treatment, how about something along these lines? I could do with some feedback badly :lol: Thanks for your time and patience EDIT: Sketchup file updated

Back to Treatment, how about something along these lines?

Basic idea is OK, but it needs some work still. It looks like you scaled the treatment in one direction only, so the speakers and soffits are now distorted, and things are all wonky! The slot walls are also rather deep at the front: I doubt you'd need that much depth.

3) I intend to build a 12º inclination ceiling. From the center of the room at ceiling height the treatment will descend at 12º, and will be around 0.7 metres at 3m length. Is this correct? Does this need to be on both sides of the center of the room or only on the speakers' side?

Just the front- In other words, the ceiling is lowest right at the front wall, above the speakers, then rises to its maximum height about half way back, and stays at that height from there all the way to the rear wall. Do not angle it down again!

2) I have calculated the sweet spot at 38% of the Length of the room (that's roughly 2.16m from the wall). From there I drawed a triangle with a 60º angle at the sweet spot facing the wall. At what distance from the sweet spot should I place the speakers following those 2 lines at 60º?

The speakers and your head should be at the corners of an equilateral triangle. In other words, the distance between the speakers is the same as the distance from each speaker to your head (or rather, to the point just behind your head where the acoustic axes of the speakers intersect). Once again, the 38% position and the equilateral triangle are only GUIDELINES! They are not written in stone, and nobody will arrest you for violating sacred acoustic laws if you have to adjust the geometry slightly to make it fit your room better. :) - Stuart -

Soundman2020 wrote:

Basic idea is OK, but it needs some work still. It looks like you scaled the treatment in one direction only, so the speakers and soffits are now distorted, and things are all wonky! The slot walls are also rather deep at the front: I doubt you'd need that much depth.

Stuart, thank you so much for your answer. I know you probably have many much more important things to do, but I would like to ask you if you could spare a little second to give me some more insight on the proportions, especially for the speakers soffits and the slat walls. I am reading all I can on the matter but, TBH there is so much info to digest I can barely keep up with it... I also have a couple more questions (easy ones) :mrgreen: 1) Can I (should I) place hangers inside the angled part of the ceiling? 2) Maybe I could use Superchunks at the back corners as the hangers seem to be a bit of a problem with the door in the way. I could build part of the Superchunk on the door side on the door itself in a way that the door can open/close? Thanks very much again for your help and support :) Cheers