Bedroom Design

Hi all! It's great to be back here. Unfortuniately I was never able to build the desigh John helped me out with in my basement, I was forced to keep it in 2 spare bedrooms. :roll: So, Currently my control room is 11' x 11'. I am running out of room and decided that I will move my bed in there and use the larger bedroom that is 11 x 13. So I have 1 or 2 questions. My current room is a flip of this one (the front of the house) The desk has an angled top. I have 703 panels to each side of the listening position and above the couch behind the mix desk and everything seemed to work OK, even metering with a RTA. In the new room, the front walls will be built like it looks as slots, or I may build slot panels and mount them to the walls. The rear wall will be absorption (cloth over 703) I am really looking to set up a nice room for some new speakers and to take my mixing to the next level. Question: My new studio monitors are event asp8 (they'll arrive in 6 days) and I know they have a bit more low end then my 20/20bas. The couch I have is very fluffy and worked pretty well absorbing bass freqs before, but do you feel I need more bass absorption? Thanks so much for still being here! :D Tom P.S. Here's a plan and a picture of my doggie. Hey John, she's part dingo :wink: an australian cattle dog!

Shouldn't make that much difference other than maybe a couple of lower frequency modes getting rattled a bit; you may want to consider (if there's a window like that in your new location) building a thick rockwool gobo for behind the speakers, next to the window (but closer to the speakers) - to counteract SBIR and smooth out the bottom end somewhat... Steve

Thanks for the reply Steve. When you say rattled do you mean rattled by the window or the modes? There is a window the exact same size in the new room.

Cute doggie... :-) ...And nice desk -- is that custom-made? 8)

Thanks. She loves to hang out under the desk when I'm mixing and tracking. I designed and built the desk from scratch to hold my DM-24. :) It took about 4 days to build. I've been thinking about cutting a couple racks in the top to either side of the mixer to lose my rolling rack and it would keep my ears in front of the speakers while I fiddle with the sound.

The board is recessed, isn't it? 8) Very cool!

The board is recessed, isn't it? Very cool!

Sure is and it's on casters too! :wink:

Hey Sharward, If you have some free time to read http://forum.studiotips.com/viewtopic.php?t=107 He kept a diary similar to yours of his studio build. You remind me of him (I've read some of your adventure after you responded here) and I figured I'de share the link. 8)

Oh, indeed, I'm quite familiar with Paul's thread -- I'm a regular subscriber and he inspired me in a lot of ways! ;-) I'm honored and yet humbled to be considered to be a member of the same club as Sir Woodlock. :-)

When you say rattled do you mean rattled by the window or the modes? Sorry, I just meant that the increased low end output might excite the lower freq room modes a bit more, so you might need a bit more corner absorption - Although, have you done any swept sine waves in the room yet to check for actual rattles? Most rooms will have a few at least... Steve

Happy new year! I am getting ready to order materials tomorrow for the room and I wanted to get your blessings before ordering. My ceilings are 8' tall. The 703 I will be getting in 4 x 8 sheets and I am thinking due to the large size it will help out the lower frequencies. Basically, I was going to screw track to the floor and ceiling, slide in the 703 and support it vertically with two studs calked and screwed back to back. The 703 would be stood up on end. Look all right?

Don't think you're gonna like having that large of 703 sheets only supported on 4' centers, especially 8' tall - the stuff just isn't stiff enough not to sag. Are you planning on a complete coverage of all walls, or what? Steve

That would be the rear wall in the picture and the front 2 walls would be splayed slot resonators on both sides of the listening position.

I guess I could cut them in half. and do 4x4. I have some 2x4 703 panels and they seem sturdy when I try to bend them long ways. I was trying to do something that was not perminent because I may be selling my house in the spring and relocate to North Carolina.

Maybe something like this? Steve

You are an intuitive man, Steve. After my last post I went out to dinner and was thinking of the same thing, except for the impaling clips.

There ya go; must be the right answer then... :wink:

Last couple questions i couldn't find an answer to: Question 1: I have seen two different ways slots are made: A- The 703 is directly behind the slat and B- The 703 is on the wall behind the slats. I'm not sure which way to build them as of seeing these two ways this morning. I suppose if the 703 is directly behind the slats, it would have to be recessed somewhat to allow the slats to resonate. Question 2: Knowing the problem modes of my room, should I tune the resonator to help out those frequencies. Should I even worry about them. I've attached a picture of my mode results. I know slot resonators only go down to a low mid octave and wouldn't be able to attack the very low problems. I could calculate using the .xls file, but I think it is only for a fixed depth, right? Question 3: I am considering using sanded plywood for the slats on the resonator because the wood would match my mix desk. I know what you're thinking, but no, Martha Stewart has not been advising me :wink: Are there considerations to be made on using plywood vs pine? The vertical studs will be 18" on center. I start today the framing and will post pictures! Thank you for all the help :) ciao, Tom

Question 1: I have seen two different ways slots are made: A- The 703 is directly behind the slat and B- The 703 is on the wall behind the slats. I'm not sure which way to build them as of seeing these two ways this morning. I suppose if the 703 is directly behind the slats, it would have to be recessed somewhat to allow the slats to resonate. (A) is the correct way; although these are called slat or slot resonators, what's actually doing the "resonating" is the AIR column behind the slot, not the slat itself (although the slats CAN resonate, it's not a desired thing) - in fact, if the slats are ALLOWED to resonate instead of being somewhat damped, IMO it will usually allow the trap to contribute ringing artifacts to the room and cause more problems than it solves. Question 2: Knowing the problem modes of my room, should I tune the resonator to help out those frequencies. Should I even worry about them. I've attached a picture of my mode results. I know slot resonators only go down to a low mid octave and wouldn't be able to attack the very low problems. I could calculate using the .xls file, but I think it is only for a fixed depth, right? The .xls file is only set up for fixed depth - from what little I actually know about helmholtz, the varying depth of a corner slat resonator won't "widen" the response by as much as might be expected, because the trap will tend to "average" across the varying depth to some extent. Not sure just how MUCH of this occurs, but learned acousticians claim that in order to get the full benefit of a variable depth resonator you would need to construct some sort of "eggcrate" separator behind the slats so each becomes its own "mini-slot" with a finite depth of air column behind the slot. So far, in a corner-mounted slat resonator, what seems to work best is to use the AVERAGE depth behind the slats as a value for the spreadsheet - any "broadening of the trap response due to differing depth would tend to just make the trap seem less "peaky", and therefore less noticeable while still working to pull out the intended range of frequencies (but without losing all the highs). Question 3: I am considering using sanded plywood for the slats on the resonator because the wood would match my mix desk. I know what you're thinking, but no, Martha Stewart has not been advising me Are there considerations to be made on using plywood vs pine? The vertical studs will be 18" on center. Very little. If poured concrete "boards" match your decor, they will still work the same provided they have the same thickness, width, and spacing. Again, it's the AIR column and the measurements asked for in the spreadsheet that make the most difference. That formula, BTW, was (as near as I can tell) derived for use with 703 fiberglass from owens corning - at the time it was written, F. Alton Everest was only using that particular material. Changing the material by any appreciable amount would change its gas flow resistance, thereby changing the resonance of the trap and consequently the center frequency. Please don't ask me how MUCH, I'm still learning about this stuff myself (and will til they "pat me in the face with a shovel" - however, one of our members uses a different formula which (IIRC) requires this parameter to be entered - he claims to match calculated and actual center frequencies very closely, and has test results to back it up. Here's a thread where this is discussed - http://www.johnlsayers.com/phpBB2/viewt ... sc&start=0 HTH... Steve

Thanks, Steve :D I'm still unsure about the slat dimensions I should use to effectively tune the resonators to the room. What i've read is slats 2, 3, and 4" with varying slot gaps would be broad band absorption. The problems I see the room will have are 210hz 256hz 308hz 350hz. I know adding a 3 1/8" slat with a gap of 1/4" with an average wall depth of 8 3/4"would absorb 209hz, but I don't know how much to add into the wall to flatten down the crossing of the two modes. Would it be better to just build it to spec and add a trap on the ceiling somewhere? ciao, Tom

Anyway, before I totally fry my brain Here are some pictures of my progress from yesterday in between having beers! :mrgreen: You'll see in one picture that the slots on one side are elevated to allow the heaters room to breath. Ciao, Tom 8) One other thing, If I had a ceiling fan with concrete blades spinning at 62 rpm, would it add a flutter to the room sound. That's a bad joke eh? :P

Lookie here what I found

how many slats do i need to adjust to one frequency that it starts to work? As a rough guide (this isn't a very EXACT science) a typically designed helmholtz will absorb around 60-75% at resonance, sometimes slightly more - this is partly a function of the percent of depth of the absorbent inside, 50% fill tends to return around 70% (again, ROUGH estimate) - so, if you use 70% then each square foot of absorber face would result in approximately 0.7 Sabins of absorption AT RESONANCE. There is usually about a 2 octave range, again this is dependent largely on insulation fill. More insulation, wider range of absorption, but LOWER "Q" (less than 70% absorption) Random slats usually won't widen the band as much as expected, because the wavelength vs. absorber size causes the absorber to "average", more or less. Same with depth from wall; you can get a rough idea by using the AVERAGE depth, so if yours goes from 6" deep to 12" deep, use 9" -

What this means I have no clue, but I think I may be on to something :)

Here's A picture of the rear wall. Note: Installing 703 this way you have to slightly bent the track open to easily install it into the track. Btw, this is so easy doing it this way! 8) More later ciao, Tom

Here is a picture of the rear wall, now ready for cloth. :D Tom For the record, insulation doesn't taste like cotton candy. :mrgreen:

Just ran your room dimensions (13x11x8, right?) through a COMPLETE modal calculator, and it looks FINE. There are a lot of tangential and oblique modes your calculator doesn't show, and they fill in the gaps enough to smooth out the room's response. I'd recommend holding off on the slat resonator til you listen to your room... Steve