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Post by rock on Dec 5, 2020 19:54:28 GMT
Number 2 is the only M-A-M (remember the number 3? 3 layers- no more, no less) I can tell you this: Using more than 3 layers can be wasteful of space and resources and may also be less effective. The others are plain wrong for any room! #3 is OK if you want the outside (bottom layer of insulation) to work as acoustic treatment. BUT do you need isolation on the concrete walls? Isn't your ceiling where the sound comes from? If so you only need a single stud wall DW on the inside (room side)(the first of 3 layers is the concrete wall, the second is the air/insulation and the 3rd is the DW, if you laminate a double layer DW, it still counts as 1 layer because it's all stuck together. Either float the inside ceiling (better) or use RC (Resilient Channel, NOT top hat type). I believe Rod suggests filling the floor cavity full of fluffy better than using less mineral wool. How much/big should the air/insulation be? I don't know but more will give you more isolation. I mentioned this site generally is not the best resource when it comes to isolation but I do know a little and what I do know is mostly from Rods book. This is why I recommended Rods book. www.amazon.com/Home-Recording-Studio-Build-Like/dp/143545717X I believe this is not something that should be rushed if you want to do it as good as you can.
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Post by trombosaurus on Dec 5, 2020 21:49:28 GMT
You are awesome, and I really appreciate your time. Best Lars
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Post by trombosaurus on Dec 6, 2020 4:35:15 GMT
Hiyo. soooo, just so I understand, when you suggest that I make the room totally dead, what will that mean for me in terms of wall treatments? I played around with the AMROC tools and to me it seems like the dimensions you plugged in is the only option for getting the red x in the BOLT area, it also displays the four corners as the only problem area in the 3-d model. I'm just taking a stab at it, dunno if im doing the right thing
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Post by trombosaurus on Dec 6, 2020 4:47:22 GMT
never mind about the 3-D I realized that I didn't scroll through the schroeder bar and that changes it. do you think I am better off with a bigger room even that we can't make it wider that 9' something what would the best length be?
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Post by Hexspa on Dec 6, 2020 7:26:51 GMT
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Post by trombosaurus on Dec 6, 2020 13:22:32 GMT
Yup 7’ ceiling. And im stuck with 9’2 ish width max thno matter what. So i can only adjust the length. Any suggestions as for the best length?
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Post by rock on Dec 6, 2020 20:07:24 GMT
Regarding "totally dead": It's probably not practically possible but in small rooms, the reflections are generally undesirable so killing reflections sends you in direction of "dead". Since you're not going to make it totally dead, one goal will be to balance the absorption over the audible spectrum so that all frequency bands have the same decay time. Broadband absorbers are good for this. RT60 is the measurement for the time it takes to decay down 60dB; this is available with the REW SW.
Hexspa's video on Golden Ratios gives a good explanation for room ratios but you'll notice, it's often not possible to achieve perfection. The bolt area is for getting a good ratio too but it lowers the bar on perfection and it's an easier target to hit.
It may be obvious to you by now that the room modes are determined by the dimensions of the inside rigid boundaries and not the surfaces of the room treatment. Since you're installing a ceiling, you need to use the measurement from the floor to where the ceiling will be so you'll need to know if you're using 1 or 2 sheets of DW and if you're going to need RC channels.
Rod's book also shows how you can increase the isolation of the floor above by adding DW to the bottom of the floor from the inside. You need to consider the structural capacity of course but if you do this you also need to use acoustic caulk to sealant fill cracks between the floor and your new DW. In fact, you need to use lots of caulk everywhere to make your room air tight.
Speaking of AIR, you'll need to consider ventilation. You will probably not need heat much at all but likely need AC...even in winter so then, you might want to just mix outside air with inside for that. A home run directly to the air handler with insulated flexible duct is pretty quiet and easy to use if it's code. If not, a length of about 5 feet of flexible at the room end will attenuate much on the metal duct noise.
Electricity also need to have all entries into and out of the room acoustically isolated. Lighting should be surface mount to retain acoustic integrity.
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Post by trombosaurus on Dec 6, 2020 21:59:02 GMT
Wow there is so much to learn and so much money to spend. Speaking of,,, acoustical caulk appears to be pricey, any sources on an economical solution? Also.,,,, if this was your studio project , how long would you make the room?
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Post by trombosaurus on Dec 7, 2020 3:11:38 GMT
Oh a d. Would you coat the drywall side that goes against the subfloor with a notch trowel or just do the typical s pattern?
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Post by rock on Dec 7, 2020 4:56:57 GMT
Wow there is so much to learn and so much money to spend. Speaking of,,, acoustical caulk appears to be pricey, any sources on an economical solution? Also.,,,, if this was your studio project , how long would you make the room? Sorry, no advice on caulk prices. I'm just not in the market these days. I'd go with the Bolt area chart as it's very difficult to hit the golden ratios with 2 given dimensions. But on second thought, why don't you see if any of the golden ratios do give you an acceptable length that you can fit into your design.
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Post by rock on Dec 7, 2020 5:07:22 GMT
Oh a d. Would you coat the drywall side that goes against the subfloor with a notch trowel or just do the typical s pattern? IIRC, the method Rod Gervais gives to attach DW to the underside of subfloor is to use cleats and fasten into place and to caulk the edges. It sounds like you're suggesting using "tile mastic" to fasten the DW to the subfloor. Maybe your idea is better but maybe more material cost and labor for the expected outcome? This is where you need to ask the real expert. I suggest you contact Rod Gervais or at least get his book.
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Post by trombosaurus on Dec 11, 2020 2:02:22 GMT
hey im wondering if you think I should go with fiberglass in the ceiling, like one layer up against the subfloor with drywall strips , then an air gap and then more fiberglass against the new ceiling... I am concerned with the distance from the bottom of the existing joists to the new ceiling, even that the two ceilings are decoupled,, What kind of insulation would be best for that 1" gap to absorb the impact noise from the existing floor joists?
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Post by rock on Dec 11, 2020 5:03:42 GMT
From the concepts that I understand and NOT so much from practical experience, I would say the 1" gap is not a big deal. You just don't want to conduct vibrations from the top floor structure to the bottom ceiling structure. Acoustic vibrations produced by the joist edge 1" from the DW are probably much less than the floor/subfloor system because of less area of the joist VS the floor as well as less deflection...but this is just my guess.
I also understand that the space is best filled as completely as practical so you have some choices and I don't know what's best...BUT, if I were to guess, I say fill all the space but don't overly compress any insulation. That means cutting the insulation to fit snuggly around the beams but not to compact it.
This floating ceiling approach is apparently the "Room in a room" where the ceiling is isolated from the floor above by an inner wall system. My caution is to make sure your ceiling joists are adequately isolated from your floor joist system.
The illustration shows 1 layer of DW. I guess this is one instance where you could add a second layer if needed after testing.
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Post by Hexspa on Dec 11, 2020 14:15:39 GMT
As far as length goes, I'd say make it as far back as possible without being a 1:1 or 2:1 multiple of any other direction. For example, your ceiling is 7' so don't make it 7 or 14'. Same goes for the width. You want it at least 10' from your listening position, if possible, to delay reflections from the rear.
Not sure what a 3:1 ratio would do. Probably nothing good.
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Post by trombosaurus on Dec 11, 2020 15:26:46 GMT
Hexspa and Rock if I were to somehow find the money to do a floating ceiling in the entire room the dimensions would be 21'9x9'2" with a 7' ceilinged you think that this would be much different in terms of recording/modes etc vs 11'3"x 9'2 w 7' ceiling??? could I make moveable traps ,,, how would you record vocals in a space like that..for tracking I would have to have my computer in another room to avoid any gear sound........ thoughts? also do you believe in green glue??? will it be worth it to use GG between 2 layers of drywall ( for between the joists, against the subfloor) how much does it do for impact noise, and how much does it do for the overall performance? When using cleats to hold the drywall in place, don't you think that a cleat every so often would be sufficient vs running a cleat full length ? The more I learn, the more questions I have,,, Best Lars
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