where is my knight in shining armor?

terrible_buddhist · Post by **terrible_buddhist** » Sat Nov 01, 2003 12:23 am

Thanks Steve...so the plan for North South wall is ok?

if so, the for west wall (the one with the angled walls), I am trying to figure this out in my head...there is concrete...then the framing...then the framing for the angled wall. When we build this angled wall however there will be an awefully large air gap there (airgap about 2in from concrete to the framing, and then the gap from the framing of that wall to the framing over the angled wall. Should this area be filled, or is the gap ok? My thought here is:

Concrete to framing; framing to angled framing; insulation on the angled framing(is R-13 ok for this since I again don't have to worry about bleeding into another room & there will be a slot absorber on this wall?) then 1 layer of drywall, then attach the slot absorbers to that drywall. If this is all ok...my question then is...what is the best way to attach the slot absorbers, as well as the panel absorber to the walls themselves?

I noticed someone in one of the 'under construction' pages used L brakets for the panel absorbers, but it seems if you are going for a sealed box, this would be risky...now going back to re-read everything. Thank you for your help!

knightfly · Post by **knightfly** » Sat Nov 01, 2003 2:51 pm

Keith, sounds like you missed one small detail about the slot absorbers - the ENTIRE space behind the slats, varying depth and all, is figured into their performance - please re-read my description of the absorbers on the previous page of this thread, you'll see that the air cavity depth is part of my calculations. This means that you can't put drywall right behind the slats, or it changes everything. The insulation you use here isn't real critical, but I'd put more than just R-13 - maybe two layers of un-faced R-19 in the deeper ones, and one layer in the shallower ones.

Re-read the page on absorbers, here -

http://www.johnlsayers.com/HR/index1.htm

About the only difference would be the shape and depth of the box - everything else should be done like the drawing.

Here's a rough idea of the way it should look, when you're ready to build them if you'll post the actual length of the rear (parallel to wall) side I can give you exact angles and possibly even a CAD drawing (basic) -

Still not finished with "life stuff", so this will have to do for now... Steve

terrible_buddhist · Post by **terrible_buddhist** » Sat Nov 01, 2003 11:56 pm

so, then these ARE my angles walls. I thought I needed to build the angled walls and then attach these to it. This will save some room

That is what I meant by putting up the drywall...not directly behind the slots, but I was going to build a wall, then attach this to that wall.

Thanks! I look forward to your other answers...hope everything is going well in life, or at least does soon. I will take those measurements on Sunday and even post a few pics.

terrible_buddhist · Post by **terrible_buddhist** » Sun Nov 02, 2003 2:54 am

here is my north wall (the wall you face when you walk in, or the top of the drawing

)

terrible_buddhist · Post by **terrible_buddhist** » Sun Nov 02, 2003 2:55 am

south wall

terrible_buddhist · Post by **terrible_buddhist** » Sun Nov 02, 2003 2:57 am

west wall

terrible_buddhist · Post by **terrible_buddhist** » Sun Nov 02, 2003 2:59 am

and east wall (or lack there of right now)

the dimensions of this room from framing to framing is about, 145 inches wide by 270 inches long.

knightfly · Post by **knightfly** » Sun Nov 02, 2003 8:38 am

" I look forward to your other answers" - I'm not sure at this point what your remaining questions are, could you re-state whatever you're not clear on?

Also, before you post more pix you need to import them into Paint and re-size them - if you've not done that before, here's how - yours were all at 1024 x 768, which caused everyone to have to scroll left-right to read posts in the entire thread. I resized them and reposted.

1. open pic. 2. click on Image, stretch&skew, then in Stretch, type in 75 for both horizontal and vertical, click OK. 3. Click on Image, Attributes - type in 770 for width, 575 for height, click OK. Save to your pix folder, then when you post you click browse, point to that pic, and you're there.

Other than sealing everything, your slanted traps (because they ARE slanted) aren't overly critical in dimension other than the slat width, slot width, thickness of the slat wood, and SEALING - (don't forget the cloth behind slats - fairly thick, but if you put it over your face you should still be able to breath) - All the important dimensions are on page 2 of this thread - that section of "wall" could be anywhere from 6 to 8 feet long and would be fine. You could actually build each section of the trap separately as a free-standing unit if it makes things easier.

Let me know what questions you still have, and PLEASE resize your pix before posting them. Thanks... Steve

knightfly · Post by **knightfly** » Sun Nov 02, 2003 8:40 am

Got your PM (finally) over at HR, my email is in limbo from old to new so didn't get notification. Must be working for posts here again, judging from the dates?

terrible_buddhist · Post by **terrible_buddhist** » Mon Nov 03, 2003 8:27 am

sorry to keep harping on this, I just want to be absolutley sure before I go and screw something up...

The slat resonators, I will be building them right onto the studs I have now, since the SR's are already angled, there is not need to put angled walls where the slat resonators are going. Further, I don't have to insulate behind them or anything...just build them to your specs.

Thank you for your patience with me, and sorry about the pics, I just wanted to get you the pics and dimensions you asked for and was on my way out the dooe.

knightfly · Post by **knightfly** » Mon Nov 03, 2003 11:02 am

The box that is the internal part of the slat resonator DOES need to be sealed - the slat resonator works by controlling the speed that pressure changes are allowed to happen within the box - it does this by the depth and width of the slots between the boards, and the width of the boards compared to the width of the gaps (slots) between the boards is what determines the percentage of perforation. All this works together to make a Helmholz resonator. The ONLY access your sound should have to the area behind those slats is THROUGH the slots between the slats. Period.

Some quotes from the SAE site on Wall Units -

"The box created must be completely sealed to be airtight. The only access to the outer air is via the gaps between the slats."

"The rear of the unit is covered by plywood to create a sealed unit." -

I know you're still very new at this, but one of the things you MUST learn to do is read carefully. Acoustics is FULL of little details, and very few of them are insignificant. Without these details, you're just another framing carpenter - WITH them, you're an ARTIST... Steve

terrible_buddhist · Post by **terrible_buddhist** » Tue Nov 04, 2003 12:27 am

I must be phrasing my question poorly...I absolutly understand the idea that this has to be a sealed unit.

My question is what needs to be behind the unit. In other words, do I create an angled wall, and then attach this unit to that wall...or in effect does this unit take the place of the angled wall since it, itself is angled. If this unit is in fact the wall, will the dimensions be enough to create the needed 12 degrees.

knightfly · Post by **knightfly** » Tue Nov 04, 2003 4:20 pm

Sorry, I must have misread something. Yes, the unit, if built like the drawings, has plenty of angle to take care of flutter, no problem. To just handle flutter echo, all you need is about 10-12 degrees. 12 degrees is about 1 foot in 5 feet, you'd have TWO feet in only EIGHT, so the angle is more than adequate.

All you need to do is build the angled trap(s) and lean or fasten them up against your (straight) walls where they're shown on the last drawing, and you're set... Steve

terrible_buddhist · Post by **terrible_buddhist** » Wed Nov 05, 2003 1:00 am

ahhh...I can now sleep

That was bugging me big time. My next question that is keeping me awake at night is, what is the difference between the live side of the room and the dead side?

terrible_buddhist · Post by **terrible_buddhist** » Wed Nov 05, 2003 1:03 am

oh...and I don't actually have to put drywall or insulation behind these units right...because they are essentially self contained. Just making sure.