Materials for slot resonator??

Ok i want one with the varing slat size and gap size. I was thinking sheets of 8x4 1/4" (or is 1/2" better)ply cut on a table saw to say -1" -2" -3" -4"? Also does the rockwool have to have a gap infront AND behind. I want it to look like this But cant figure out there sizes? thnks

Bryan, I deleted your cross-post from the construction forum - first, cross-posting takes up more of our time by duplication of effort - second, John and Barefoot have different ideas on the value of variable slot/slat width resonators - third, I've not build one yet but Barefoot's comments made sense to me - check out this link - http://www.homer.com.au/phpBB2/viewtopic.php?t=176 4th, do you have the hemholz calculator from the SAE site? If you plug in 4" slats 1/4" thick over 2x4's, you end up with a resonant frequency of around 330 hZ - changing to 1/2" thickness lowers it to 300 hZ - one point being, without knowing what frequencies you're interested in absorbing it's not possible to answer your questions... Steve

Thanks for the reply. well im really going for a wideband absorbation thats why im making a triangle shaped one. im actually going for the 300-400hz anu up range as im also putting eathans design low bass traps in the corners(2 7' ones in each) I think this makes sense please correct me if im wrong. whats the real world performance of slots and bass traps? how low high? I have also planned to but a 4'x8' 3" rock wool panel covered in cloth about 6" deep each side of my listing position, how do i work out its absorbtion frequency?? above me im putting 2" acoustic tiles as seen here http://www.studiospares.com/productdeta ... gid=1&cid= as i have a wooden floor. am i missing anything obvious. thanx again

Bryan, I think the thread Steve meant to link what this one. http://www.homer.com.au/phpBB2/viewtopic.php?t=132 It more directly addresses the issue of bandwidth versus slot/slat variations. And like I mention is this thread http://www.homer.com.au/phpBB2/viewtopic.php?t=167 the major concern about absorbers isn't their frequency range. You can come up with whatever you like in that regard. The question is how much energy will the resonator actually absorb. If you want a resonator that is simultaneously low and efficient, it must be very large. There's no getting around it, whatever the design. Thomas

thanks thomas that was helpfull, Just one more thing does the whole thing have to be air tight?? because im building it on to a pre-existing frame thats already out from the house wall so looking down at just the studs including the ones for the resonator would give thisd should i seal where the stars are air tight???? thanks

should i seal where the stars are air tight????

yes - the only air access should be through the slots cheers john

Hey, nice picture! Looks kinda farmilair! Say, from my drum room! Geez, I never thought people would be using my stuff as an example to go by!

Hey, nice picture! Looks kinda farmiliar! Say, from my drum room! Geez, I never thought people would be using my stuff as an example to go by!

Wow, gratification in STEREO... :=) See, now you're nearly famous. Now, if we can just control that spasm in your mouse finger... (in my case, I actually have a glitch in my mouse/driver that does things like that FOR me - that's my story, and I'm stickin' to it...)

Hey, nice picture!

hey - nice slots - hope you don't mind us using it as an example :):) cheers john

John Sayers wrote:

Hey, nice picture!

hey - nice slots - hope you don't mind us using it as an example :):)

No problem, considering it's your design I stole! 8)

I've got a couple of different materials questions about slot resonators: 1) I know the designs talk about using MDF. Nice thick strong MDF. Problem is that my son has chemical sensitivities and getting MDF that doesn't outgas formaldehyde is $$$. Would I lose a ton of effectiveness if I built the box out of pine? 2) How do you attach the cloth behind the slots? Do you glue it to the slats, or to the sides, or does it not matter much? 3) I saw in a different thread that I can't find right now that you could use foam inside instead of rigid fiberglass. Can you also use the fluffy fiberglass insulation or would that degrade the effectiveness? Thanks much! -lee-

laptoppop wrote:

I've got a couple of different materials questions about slot resonators: 1) I know the designs talk about using MDF. Nice thick strong MDF. Problem is that my son has chemical sensitivities and getting MDF that doesn't outgas formaldehyde is $$$. Would I lose a ton of effectiveness if I built the box out of pine?

Lee - you can use pine to make the box - not a problem.

laptoppop wrote:

2) How do you attach the cloth behind the slots? Do you glue it to the slats, or to the sides, or does it not matter much?

YOu staple it to the studs that form the front of the box. NOTE: If you are building a studio a hand operated or preferably air driven staple gun is a must!! Take a look at Luis construction. The first pics show his triangular box shape that will become his slot cavity. Note it's sealed all the way around.

laptoppop wrote:

3) I saw in a different thread that I can't find right now that you could use foam inside instead of rigid fiberglass. Can you also use the fluffy fiberglass insulation or would that degrade the effectiveness? Thanks much! -lee-

Yes you can use foam etc. Cheers John

Thanks John! Yes, I *do* have a staplegun ;) I'm building free standing resonator boxes that I will attach to the wall. I need to make my construction removable/reusable. So when you say "studs" I'm interpreting that as "sides". Where can I find Luis's pictures? I would expect somewhere in the studios under construction area, but I don't know the name of his studio. Thanks again, -lee-

Luis is S.Productions lee. cheers john