Are there any examples that you know of that I can look at? If I put up wood, doesn't that turn it into a three leaf system?
If you read pretty much any threads on this forum, they are inside out builds. So hopefully you can find enough pictures to clarify any questions you may have.
It wouldn't be a 3 leaf system because your outer leaf only has one layer of mass, then your inner leaf (which is inside out) has one layer of mass. That's it. Nothing more.
OK, what about the outer leaf? What am I doing with that? That has no insulation or anything in it right now. Am I just putting insulation in it, putting insulation and drywall, doing nothing, or something completely different?
You make it so that it is air tight. Imagine filling it with water. Is there anywhere the water would leak out? If so, seal it. There should be NO spot on your entire outer leaf that has less mass than your minimum amount required. This is why you box in existing mechanical stuff. This will also require you to extend your walls all the way to the foundation and seal it all up.
Then, between this outer leaf and your inner leaf, you fill it completely with insulation. For your inner leaf drywall that is facing the foundation, you will need vapour barrier fixed to the drywall before you stand the wall up.
OK, I also have room, and more of it on the opposite side in the HVAC room. The A/C went is currently in the middle of the room in the ceiling. If the first box is on the outer leaf in the sump pump room, how am I getting it from the A/C vent to that box? Am I using additional duct work? I would assume so, I just want to make sure you're not referring to moving that vent.
You will have to re-work the duct work for your room. I presume there is no way you're going to be able to run a designated HVAC system for the room. It sounds like you're planning on using your existing home unit. Now, the only problems with this idea are:
- Say your jamming and sweating your butt off but the rest of your home is comfortable. The thermostat isn't going to see a problem and it won't turn on your A/C. So what do you do then?
- Since your room is air tight, there is only fresh air brought in when your air handler blower is running. The only way you're going to get fresh air while you jam is to run your blower all the time.
- Can your air handler unit fan handle the extra static pressure drop introduced by your silencer boxes and extra duct work?
The other option would be to install a ductless mini split then install duct work to remove stale air and give you fresh air. These would be small ducts as they only need to swap out 30% of your calculated CFM for 6 air changes per hour. That means smaller silencer boxes too. BUT, you will need to cut holes on the side of your house to dump stale air and bring in fresh air. This is also quite inefficient energy wise. So, to fix that problem, you could use an HRV. Typically you can away with using the HRV built in fan to move the air for you as well!
This is an expensive fix though.
It does need to stay and I would not want to remove it but where it is right now, it would not interfere with the inner leaf ceiling. Couldn't I just leaf it as is if that is the case?
I don't fully understand your question.
Right now we're only worried about the acoustics with the low volume cymbals as well as the electronic set pad noise, correct?
Sure. You have to decide that, not me.
I don't think we're talking about full blown acoustics because I think we determined there would be too much involved there.
So you're not doing a room in a room? I have a lot on my mind and might not be following your thread entirely at this point! I hope we've provided you with enough information to make an informed decision about the type of construction you need to build to perform as you require.
Do we really need to worry about the four boxes in that case? What if I went straight down from the vent with an extension into the inner leaf with some type of baffle system, then out of the inner leaf into the HVAC room with one or two systems?
Okay so I'll clarify how many boxes you need:
Each leaf needs a box. If you don't do a room in a room, you need 2 boxes (one supply one return). If you do a room in a room, you need 4.
I'm not worried about the sound in my own house just the neighbors.
This goes hand in hand. You either have isolation or you don't. You can't control who gets to hear it and who doesn't. The sound either stays in/out of your room for everyone or no one.
Greg