12'x10'x8' Tracking Room Plan Suggestions

I measured my room and came up with a plan for treatment. Any suggestions would be greatly appreciated. So far I have tried 8 MiniTraps in the corners ( 1 across each wall to wall intersection and wall to ceiling intersection) and have not achieved my desired sound; I want some sparkle without the problems from the mids and lows. I was thinking of using the panels on the ceiling instead. The floors are oak hardwood. The position of the door, windows, and closet make this a pain in the arse to layout nicely. I can't cover the door which is situated in a corner, and the windows take up the whole rear section. I could place a huge panel over them but that would probably deaden the room and make it dark. So I thought curtains for the windows. This will be a tracking room only but suggest anything you want. The more ideas the better. Space is kind of limited for a dual purpose room and I wanted to achieve a good tracking room for acoustic instruments and vocals foremost. I was thinking of turning the closet into a huge slat resonator for low frequencies or simply putting a big movable fibre glass panel in front of it. There are windows at the bottom section. I included a layout of what they look like when you face them.

maybe something like this? cheers john

Thanks very much John :D I'm no expert but I can kind of see what you're doing. The bottom is sort of mimicking an open space with the absorption and the top is funneling the sound into it. That's how I interpret it at least. What is the green thing in front of the hanger traps? Is that a fibre glass panel? Is this a combination of panel and hanger traps? Or is the green panel something like a plywood board that will let only low frequencies through? I've read somewhere that hanger traps have to be very exact to work properly. These are basically fibre glass panels hung to a very precise length in relation to each other right?

yeah - the green is just a cloth front - i.e take the doors off the cupboard. The slots are designed to break up the parallel walls, absorb the low mids yet keep the highs. the hangers are sheets of celotex wrapped in insulation and hung by wires. Use as many as can comfortably fit in the area. cheers john

Is using a fibre glass panel in front of the closet a bad idea? I was thinking the panel would absorb what it can, then the baffles would get the rest. Or would the panel interfere with the effectiveness of the baffles? Is there a resource out there that has more information about acoustic hangers? The "Master Handbook of Acoustics" doesn't mention them. "Building a Recording Studio" does, says they have to be precise lengths and distances from each other but then doesn't elaborate any further. Here's what it says: "When an approaching sound wave strikes the baffles, it is caused to diffract, thereby hitting other baffles in the immediate vicinity. The process repeats, eventually dissipating the sound energy of the wave. In order for the broadband absorber system to work porperly, the baffles must be hung in predetermined configurations. Each baffle must be spaced at a critical distance from the baffles surrounding it. The configuration and critical distance are determined mathematically and vary from one application to another." What is the mathematical principle I should understand before implementing this? Did some searches but didn't pull up anything except for commercial versions of them. Is there somewhere I can get the full scoop on these? There used to be a link on homerecording.com to some huge index of information. I think I lost the link after a clean OS install. Anyone know the one I'm talking about? It's not a sticky at homerecording.com anymore. It's an extensive guide to just about anything to do with recording, with links. I thought I could find the info there.

I'm ready to buy the materials and build the slats but I still had several questions that I was hoping someone could answer before I start. I’m a little uncomfortable starting the building process without fully understanding what I’m doing. I'm going to use the design you provided John, and cut off the little section extending towards the door, for simplicity: I looked at Blue Bear studio and I see they follow this pattern: largest gap(4/8''), medium gap(3/8''), small gap(2/8''). It seems this is a good way to hit a broad range of frequencies for a wide range of room types. I see also that the slat width is thicker on an adjacent section. All slat widths are the same on each section. That is, there is no variation in each individual section as shown in the original plans. http://www.johnlsayers.com/HR/index1.htm Original plans http://www.johnlsayers.com/Pages/Bluebear.htm The link for Blue Bear I was thinking of putting the lowest reaching slats up top to counterbalance the heavy absorption in the lower right. It makes more sense to put them in the large volume triangle where I have more ability to actually absorb them once I trap them. I think I've figured out how to calculate the overall depths. Since the triangle at top reaches a depth of 2', the average depth would simply be 1’, correct? If I separate the top triangle with a separator down the middle does that halve the average depth for the left section or do I continue to use the 1’ average depth for both sections of the top? How about the odd shaped middle triangle? Would I divide that into two right angled triangles and then average the middle length of 1’ to 6’’ for the average depth? 1. If I use 2’’ thick slats at top to reach 98hz will I actually achieve absorption in this range? In other words, can I realistically expect absorption under 100hz with the volumes available? 2. Does separating the cavity behind the slats affect my calculations? For example, if I put a separator halfway between the top resonator does the left most portion now have a new average depth of half the original or retain the original 1’ value? 3. If I vary the slat width from 2, 3, and 4 inches on an individual resonator, and also vary the slot width from .25, .375, and .50, will I achieve even absorption at 138, 167, 190, 215, 226, 255? I see that 190 is hit 3 times surprisingly. Do I simply alternate 4, 3, 2, 4, 3, 2 or is there a more effective method of variation? What I mean is, could I just put all the 4’s at the bottom, all the 3’s in the middle, and 2’s at the top with varying slot widths and achieve the same result as I would with going 4, 3, 2, 4 , 3, 2? To achieve this broad range on a single resonator do I sacrifice effectiveness? For example, would a resonator with all slats at 4 inches width be more effective at its target frequencies than a broader range resonator that had one spot in its surface designed for this same frequency? 4. After doing the calculations, using the average volumes of 1’ for the top and lower right triangles, and 6’’ for the middle triangle, I found that the highest range I reached with the universal values given of 2’’, 3’’, 4’’ for slat widths, and .25’’, .375’’, and .50’’ for slot widths was 360hz. Is this sufficient or should I aim for higher values on one or all of the resonators? For example, should I design the middle left resonator with custom slot widths and slat widths to reach up to 500hz? Would this one resonator be sufficient to pull off the job or should the lower left resonator help in the mids? 5. For this room would I be better off varying each resonator or specializing each resonator for a certain range? I was planning on making the top most resonator the low absorber(1.5’’ or 2.0’’ thick slats), the bottom left the mid absorber, and the middle left resonator the high mid absorber(custom values to reach 500hz). Is this a good plan of action or should I make each one more varied? For example, instead of using all 4’’ slat widths at top would it be more prudent to vary them 2’’, 3’’, and 4’’? Same for the rest?

Can anyone help please...? I still have these same questions.

is this what you wre looking for?? http://www.saecollege.de/reference_material/index.html cheers john

Thanks John. I've already been there several times and find it to be a very informative site. It's a bit brief though. There are no real explanations on why certain widths are used and certain slat dimensions used and an overall strategy to use depending on the room modes present in your room and your room dimensions. There is a lot of information on slat resonators here on this forum that I have read, but the thing is it's all scattered around. You go searching for one part, and then for another question you sift through a few hundred more. It would be easier if it was done in a sticky. If there was a sticky with the full scoop on resonators I think it would answer a lot of these questions. I'm sorry, I don't mean to sound demanding or anything, it's just my perspective of the situation. I realize you do this for free and the people here help out for free and I greatly appreciate that. I've learned a lot but I feel there are still many unanswered questions. I think if there was an example of how to go about designing the slat resonators for a specific situation that would be helpful. For example: A room like mine is a very specific situation. What slat widths and slot widths would you choose for which parts of the room? Why would you place certain widths in one spot and not another. Why does a studio like blue bear have slot resonators with no variation in slat width per wall? This kind of specific information is what I'm getting at. I came up with certain numbers to use for the different sections but I'm wondering if these are good numbers to use since I've never done this before. I just want to avoid wasted effort and materials. I'm still left with these questions. Either I'm just not getting it or there isn't enough information or knowledge about these for me to get it... perhaps a little of both. Cheers, Lex

Lex - if you look closely at Blue Bear you will see there are two sized slats - 6" and 4". The gaps don't vary because the depth off the wall varies as those slots are angled to the wall. It's not about aiming for 200hz - it's about having a broadband across the 200hz range so you have one set of slots working in the 150 - 300hz area and another in the 300 - 500hz area and the 703 does the rest in the upper range, 500hz up. If you take a look at the stickey with the 3D basement studio you'll see how to build your slots. hope this helps. cheers john

I see, so if you have an angled slat wall like in my room you have no need for varying the gaps? So the difference in depth makes introduction of differing size gaps for more of a broadband or range, overkill? That makes sense now that you told me... I didn't realize that the depth would be enough, though I knew it played a part. I suppose if you're going from 0 depth to 2 feet you must hit a wide enough range of frequencies. Thanks for clearing that up, I was experiencing cognitive dissonance. :? What did you think of my strategy? Making the top set of resonators lower than the bottom 2? Does it even matter which one's the low one? I'll take a look at that 3d Basement Studio, thanks John.