You’re welcome
No so I mean 1 box on the outer leaf going through to another box on the inner leaf for your inlet fresh air
Then another box on your inner leaf going through to another box on your outer leaf for your outlet exhaust air.
2 per inlet and 2 per outlet.
Paul
Planning/Starting basement studio build. Here's my questions
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Re: Planning/Starting basement studio build. Here's my quest
So If I have silencers in the control room and silencers in the live room, I'd end up with 8 silencers. Got it.2 per inlet and 2 per outlet.
So in the context of a single room, would fresh air inlet box on inner leaf (box 2) be the same size as the first box on the outer leaf (box 1)?
I'm just trying to understand the general concepts around the sizing.
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Re: Planning/Starting basement studio build. Here's my quest
Yes, they can be the same cross sectional area and volume and size but they don’t have to be the same shape.
You need the inlet box on the outer leaf to be fed fresh air from the outside, then the outlet box on the outer leaf needs to exhaust the air directly to the outside, usually powered by a fan. The inlet and outlet boxes on the inner leaf are connected to their respective “twin” on the outer leaf via a small length of flex duct in the cavity or some other kind of resilient joint to keep them decoupled. Every box should be made from mass that has the same surface density as the walls they’re attached to, and obviously sealed air tight, especially around the penetration. Usually they have a sleeve which goes through the walls and connects to the flex duct in the cavity, the sleeves must also maintain the same surface density as the walls. You also need to use proper duct liner inside the boxes.
Greg has become the master of designing properly sized baffle boxes, I’m sure he will help you. Later I’ll try to find all the formulas for helping you work out the correct sizes for your rooms.
Paul
You need the inlet box on the outer leaf to be fed fresh air from the outside, then the outlet box on the outer leaf needs to exhaust the air directly to the outside, usually powered by a fan. The inlet and outlet boxes on the inner leaf are connected to their respective “twin” on the outer leaf via a small length of flex duct in the cavity or some other kind of resilient joint to keep them decoupled. Every box should be made from mass that has the same surface density as the walls they’re attached to, and obviously sealed air tight, especially around the penetration. Usually they have a sleeve which goes through the walls and connects to the flex duct in the cavity, the sleeves must also maintain the same surface density as the walls. You also need to use proper duct liner inside the boxes.
Greg has become the master of designing properly sized baffle boxes, I’m sure he will help you. Later I’ll try to find all the formulas for helping you work out the correct sizes for your rooms.
Paul
Paul
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Re: Planning/Starting basement studio build. Here's my quest
Oh yeah, I've done so much reading on the actual construction of baffle boxes, but was unclear on the port sizing, but that's cleared up. I'm certainly interested in any feedback you or Greg have.
Would Sound Seal duct liner work? It's pretty hard to find JM LINACOUSTIC R-300 that's actually for sale to non HVAC contractors.
One more question about construction. I'm going to add 2 layers of drywall (+ backing rod/caulk) in between joists against the upstairs sub-floor. Should I block off the spaces above the wall top plate with a similar treatment, or would this cause problems (like a three leaf type of situation)?
Would Sound Seal duct liner work? It's pretty hard to find JM LINACOUSTIC R-300 that's actually for sale to non HVAC contractors.
One more question about construction. I'm going to add 2 layers of drywall (+ backing rod/caulk) in between joists against the upstairs sub-floor. Should I block off the spaces above the wall top plate with a similar treatment, or would this cause problems (like a three leaf type of situation)?
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Re: Planning/Starting basement studio build. Here's my quest
Technically speaking, the more abrupt cross sectional area changes there are, the more insertion loss you will achieve. However, with every abrupt change in CSA or direction, comes an increase in static pressure. If you increase the static pressure in a system, you will need to upgrade your inline fan to one that can handle the extra load. With that comes higher electricity consumption. So, there is always a trade off just like every other facet of studio design!Oh yeah, I've done so much reading on the actual construction of baffle boxes, but was unclear on the port sizing, but that's cleared up. I'm certainly interested in any feedback you or Greg have.
So, to more directly answer your question, the CSA between your inner and outer leaf silencers can be the same as the duct feeding the system (the small CSA). You will yield great results if your impedance mismatch is greater than a factor of 2. Therefore, if you do have the space to make the silencer paths 4 times or 16 (this is extreme of course) times larger than the feeding duct, do it. Also, in my experience/real life tests, 1 great big box is better than several small ones even though they have the same equivalent cross sectional area. So if you have to use a few smaller boxes, add 1 or 2 extra baffles and make their path as long as possible (picture really long skinny silencer boxes).
Another cool trick is to Y split your silencers. You'd be building a normal silencer that has twice the CSA in the box path, but you'd add an identical one on the other side. This will ultimately quadruple your CSA and halve your air velocity. Killer, yes. But realize that it will be eating up twice the space and twice the material.
That stuff looks fine, yep!Would Sound Seal duct liner work? It's pretty hard to find JM LINACOUSTIC R-300 that's actually for sale to non HVAC contractors.
As Paul mentioned, it all comes down to if you are going to actually isolate your space. If you want isolation and are able to block off only the cavity of your fireplace, you're never going to get ANY decoupled inner leaf, period. You'll always have flanking through the fireplace. Therefore, the best isolation you can achieve will be that regulated by the Mass Law equation. If this is the case, then your inner leaf sheathing (the two layers of drywall) will be the only thing stopping sound transmission (note, you will always have structure borne sound transmission). That means you don't have to worry about beefing up the bottom side of the subfloor above.One more question about construction. I'm going to add 2 layers of drywall (+ backing rod/caulk) in between joists against the upstairs sub-floor. Should I block off the spaces above the wall top plate with a similar treatment, or would this cause problems (like a three leaf type of situation)?
Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
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Re: Planning/Starting basement studio build. Here's my quest
Of course I literally just started doing this today after putting it off for a month. And it sucks.That means you don't have to worry about beefing up the bottom side of the subfloor above.
Fortunately I started in the room that doesn't have the fireplace. If I decide to decouple that room instead, would I need to block up the space above the top plate?
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Re: Planning/Starting basement studio build. Here's my quest
Yes. For isolating, you should have both your inner and outer leaf air tight.If I decide to decouple that room instead, would I need to block up the space above the top plate?
Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
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Re: Planning/Starting basement studio build. Here's my quest
Hi all, I've been doing some redesigning on this after getting your feedback, and was trying to figure out the firestops if I have double stud wall. I was wondering if this would work without breaking any decoupling?
Other suggestions I've seen have said to caulk the whole gap between the walls using insulation as a firestop and also as a backer rod for the caulk, but that seems like a large gap.
Other suggestions I've seen have said to caulk the whole gap between the walls using insulation as a firestop and also as a backer rod for the caulk, but that seems like a large gap.
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Re: Planning/Starting basement studio build. Here's my quest
Just wondering if anybody want's to take a look at the firestop above and if that would work?