Originally Posted by Livin
I have read a lot of threads and done a lot of searches but still not sure the best bang for the effort (not really a $ issue) for a multipurpose room so you help/experience is HIGHLY appreciated.
I'm turning my finished basement room into a multipurpose/media room and have a few issues I want to greatly reduce without tearing out all the drywall
What are your goals and what are your constraints? The more specific you can be, the more on point to your needs others' responses will be.
I'll start out by saying the end result is directly proportional to the amount of effort you put in to this project. IMHO, if you are looking for significant improvements in external sound reduction (which it sounds like you are), then if you are not willing to put in considerable effort I would suggest you don't change anything. To wit: installing a solid core door is going to be a pointless endeavor unless you also make substantial changes to other parts of the room.
Now, that said....
I don't want the mess/expense of tearing out the ceiling and I'm not modifying the walls (other than some treatments).
Personally, I don't think that's a big deal - in general - when it comes to the ceiling. Many people don't want to deal with the ceiling. You will of course get much better results by putting a concerted effort into damping it, but you can get good results (certainly better than what you have now) by adding additional layers of drywall to your existing ceiling.
Impact and flanking noises are common problems in basement HT rooms, and much of that comes through the ceiling. So, if you don't decouple it and only damp it, your results won't be as good (but they may be acceptable to you and would certainly be an improvement to your current situation).
However, with regards to your walls.... see below.
The basement ceiling is insulated with white batts of something encapsulated in perforated plastic(?)
Sounds like insulation and the plastic is there to hold it in place. If it were along an exterior surface it would likely be a vapor barrier, but you shouldn't have a vapor barrier with an interior partition.
Would I see a lot of improvement adding a layer of 5/8" drywall attached with Green Glue to the 1/2" Dryawall already on the ceiling? I don't expect silence but if I can reduce the sound by ~3x that would be great. Kids talking translates into about 40-60db in the basement, where moving chairs, jumping on the floor, etc hits up to 70-80DB.
"A lot" is a subjective term. IMHO, in your case you'll see a mild improvement, but you will still hear those noises. If it were me, adding a single layer of 1/2" or 5/8" drywall + GG - under your circumstances - would not satisfy my interest in better sound proofing. Now, if you added 2 layers and installed staggered studs in the walls, you'd get a better result and if I were you, I'd probably call that good enough.
2) Wall with Furnace:
One wall to the media room has the furnace. The wall is small (approx 4x8 w/ a 28" door) tearing out the drywall in this case is fine but if I can avoid even better. I will be replacing the door with a solid core and threshold drop to block sound from under the door escaping. Furnace is not super loud but is noticeable when watching TV/Movies (notice level is about 40db from the Furnace - with hollow core door)
The orig owners didn't insulate that wall and the furnace is only 1" away from the wall studs on facing the furnace (no drywall on the furnace side) so no easy way to access the inside of the wall, I could slip ~1" board between the wall studs and the furnace. Anything non-rigid would be a lot harder to get in.
If you are averse to drywall work, why not contract it out?
If you can come up with a solid plan and pay someone to do the drywall walls and ceiling work for you, I believe you'll be much happier in the end. You'd still need to consider if you or someone else would construct clips & channel and/or staggered/double studs, etc. If you are willing to do those things yourself (and the demo of existing drywall), you can save yourself mucho $$$ in labor costs, if that is important to you.
The fact that you are in this forum and asking these questions indicates you have a strong desire to make this project happen.
What is a cost effective way to reduce the sounds and slight vibration (not audible) transmitted through and into that wall?
Should I do DD/GG or QuietRock? I cannot take up more than another 1" or 2" of space into the room since it is next to the entrance door.
That would help. It sounds like your best bet would be to move the furnace at least a few inches, to allow you more options in isolating its noises from your HT room. It may be worth calling a HVAC contractor and getting a free estimate. It may not be very costly, especially relative to other items and looking at it from the standpoint of sound proofing per $ spent.
3) HVAC main ducts
These run on the right side of the room - where the ceiling drops from 9' to 8'.
Only 1" between the studs and the metal duct. There is not much noise or vibration transmitted but I was thinking about adding some insulation a little for R value and a little for just ensuring I block the little sound and vibration that is there.
Are you going to build a soffit? If so, you may be able to hide or envelope that duct in the process. If not, again it's worth consulting with an HVAC contractor about options to relocate it.
What is better Roxul or Denium insulation?
I suggest you search the forum for 'Roxul', 'rock wool', and 'denim insulation.' You will find a variety of opinions. There is some controversy over the use of denim insulation since it contains boron as a fire retardant. In airborne form, boron can be irritating to sensitive individuals. That said, if your interior walls are properly fire and draft stopped, that should be a non-issue once your walls are covered with drywall, etc.
I get airflow noise on the Supply side - is there an easy way to reduce air noise from the registers?
Where is the noise coming from? Your air registers in your room? If so, it's likely due to the proximity of your room to the HVAC unit.
You need to slow down the velocity of the air flow. There are a number of ways to do this. Again, if you search the AVS forum you'll find a number of discussions on the subject. Briefly, in your case you could use dampers (but you may still find the noise to be too loud if the velocity is very high), or you could extend the length of the run into your HT room using round, insulated flexible ducts. Or perhaps you might need a combination of the two. And again, I'd suggest consulting with a competent HVAC installer with a lot of experience. They could address all 3 of these issues and then you'd have enough information to decide if you want to tackle those concerns and if so, would you DIY or hire a pro.
That's my $0.02.