[tjhall04]

Hi All,

Long time reader, and although I don't post too often, I'm hoping to get some pointers on our upcoming theater build. I've made a sketchup which also includes the rest of the basement reno (actually was kinda fun doing it).

I'm still trying to hash everything out, but I'm looking to make sure I'm ok on room basics, any suggestions for speaker placement (would like to do 7.2.4), and general soundproofing. I'm not likely going to have equipment for it (budget) until end of the year, but we're looking to have the basement completed in July. I've gone through so many of the theater builds here and I definitely am blown away by all of the stuff done here, and wish I had a larger budget for even more stuff. Below are some of my plans for soundproofing/construction of the theater:

Sound Proofing

• Decoupling (creating gaps between surfaces; limiting vibration along pathways)
  • “Room within a room”
  • Staggered 2x6 wall on all common interior areas (i.e. two walls)
  • 2x4’s on a 2x6 base plate
  • Note: non load-bearing walls, use advanced construction 24” OC for lumber savings as we’re already using 5/8” drywall
  • Furring Channel and Resilient sound clip drywall installation on all other walls and ceiling
• Adding Mass
  • 2 layers of 5/8” drywall
• Damping (adding a material to a surface to change the nature of vibrations (sound)
  • Green Glue between each 5/8” drywall layer
• Absorbing (adding material to trap air and therefore sound)
  • R13/16/19 Fiberglass batts

Other construction notes:

• Accoustical sealant and putty around all electrical boxes/fixtures
• “Backer Boxes” around all ceiling lights and speaker holes (see below); these need to go up after electrician, before drywall)
• False Wall (Accoustically Transparent, AT) to host screen; LCR + subwoofers to be installed behind
• Plan to build hidden door entrance (pocket or bookcase); contractor loved this and is willing to do it at material cost only
• I am using a contractor, I've seen his past work and it's good quality, but he hasn't done soundproofing on this level in a residential project

Existing Basement Notes:

• 8' Ceilings (slab to bottom of joist)
• Separate zone heating/AC/dehumidfier (overkill, see below) using flex duct for the theater portion
• 4-5" poured concrete slab
• We've had record snow this year (Boston) and the vast majority of it has melted. Lot is properly graded away from house, house is on a rise, zero leaks and still feels bone dry in here

More to follow...

 

[tjhall04]

Pics/Links

Current Equipment List:

- Sony VPL-HW40ES (delivered)
- Screen: TBD 126" 16:9 AT screen (likely a Falcon or Seymour)
- LCR: 3x Fusion Alchemy-8's (DIYSG, complete)
- Surrounds: 4x Volt 8's (DIYSG, complete)
- Atmos: 4x Volt 6's (DIYSG, complete)
- Chairs: 2x Straight Row of three, likely Palliser Auxiliaries (90" width constraint)http://www.avsforum.com/forum/199-f...-deals/1791986-sony-vpl-hw40es-1999-00-a.html

 

[tjhall04]

South Facing Overview:


Proposed Theater Detail 1:
Note: I'm planning on eliminating the far seat and having it as 2 rows of 3 to allow another aisle on the far side, soffits to flank both sides of the screen over the walkways.


Proposed Theater Detail 2:


http://www.avsforum.com/forum/19-de...n/837848-minimalist-approach-screen-wall.html

 

[drunkpenguin]

Very nice detailed drawings! It's going to look nice. My favorite part is the guy checking the time. Is he wondering when the movies going to start?

 

[tjhall04]

Current Basement (Pre Reno):

South Facing View:


View from bottom of stairs:


View showing supports, will be encased in 2x6 (or greater) wall


View from opposite side of basement:

 

[Tedd]

That large window and double French doors, with large glass panels, plus the smaller windows, mean there
is no sound proofing possible. Those items also allow for a raised noise floor in the room.


So you might want to rethink things.

 

[tjhall04]

That large window and double French doors, with large glass panels, plus the smaller windows, mean there
is no sound proofing possible. Those items also allow for a raised noise floor in the room.


So you might want to rethink things.

Hi Tedd,

Good points, and definitely the weak points regarding sound proofing. Regarding the french doors, those will not be inside the theater but rather the master suite (should be shown in the sketchup above). We have decided to replace the double doors (shown as french doors in the sketchup) with a secret door. Sadly, for some reason the wife won't let me cover the windows, but on the plus side, I do live north of Boston in the 'burbs with no real sound other than ambient wind/rain/whatever.

I guess I'll clarify that the priority lies in containing sound within the room and limiting sound coming in from within the house. Know it's not perfect with the windows, but does that mean I should give up on the planned treatments?

 

[Tedd]

I'm not sure what the ambient noise level is outside, but I expect it is much louder then 22 db.
Ideally, you should be aiming for a very low noise floor, to preserve a soundtrack's dynamic range.
That way you can hear a whisper or other quiet noise event, and not have a loud event like an
explosion, make you jump to grab for the volume control.


Windows act like a low pass filter. And the bigger the window, the bigger the issues. So maybe a
window plug is a good compromise? The windows get covered up, but stay accessible and you
now control noise in/out (and light infiltration). And does the Mrs understand that her desire to keep
the window exposed, means sound proofing is literally going "out the window". And that bass will be
flanking your sound proofing efforts. So yes, I am questioning if this is wasted money that might be better off,
re-alocated, or simply left in the bank?


Two thumbs up for the new door information. You'll want some mass to the door, and gaskets. You need to
keep in mind any weak area, means you undo efforts/time/money spent elsewhere in sound proofing efforts.


And what about cooling needs (+ air changes)? Another big one, with gotcha potential.


I also like the second aisle plans. Better access but I like it even more, for not having seating right on the wall.


Is that an AT screen, or is that a bedroom closet?

 

[tjhall04]

I'm not sure what the ambient noise level is outside, but I expect it is much louder then 22 db.
Ideally, you should be aiming for a very low noise floor, to preserve a soundtrack's dynamic range.
That way you can hear a whisper or other quiet noise event, and not have a loud event like an
explosion, make you jump to grab for the volume control.


Windows act like a low pass filter. And the bigger the window, the bigger the issues. So maybe a
window plug is a good compromise? The windows get covered up, but stay accessible and you
now control noise in/out (and light infiltration). And does the Mrs understand that her desire to keep
the window exposed, means sound proofing is literally going "out the window". And that bass will be
flanking your sound proofing efforts. So yes, I am questioning if this is wasted money that might be better off,
re-alocated, or simply left in the bank?


Two thumbs up for the new door information. You'll want some mass to the door, and gaskets. You need to
keep in mind any weak area, means you undo efforts/time/money spent elsewhere in sound proofing efforts.


And what about cooling needs (+ air changes)? Another big one, with gotcha potential.


I also like the second aisle plans. Better access but I like it even more, for not having seating right on the wall.


Is that an AT screen, or is that a bedroom closet?

Hey Tedd,

She usually just gives me blank stares when I talk about sound proofing Definitely will check out window plugs, seems like a good compromise. Also, this would solve my light issues (I was originally planning on doing some sort of black velvet curtain for the window), so two birds with one stone is a good deal in my book.

HVAC will be run using flex duct along the window side so I can have matching soffits on both sides; at least two bends and I'll have it with insulation as well to act as a muffler. I thought I mentioned it, but it's on its own zone not shared with the upstairs so that should help out a bit as well.

I did the aisle for ease of use but also to get some separation for the surrounds and make it easier to center the screen. And yes, it'll be an AT screen with AT panels on a false panel (similar to Big's minimal false wall).

As for ambient outside noise, think rural, we're not a passthrough road so almost nothing, very quiet residential area. I'm also not a hardcore audiophile, I just want to make sure I'm soundproofing this the absolute best I can to allow for growth in my hometheateducation

 

[Tedd]

You are chipping away at my concerns.


As for hard core audiophile, I'd call it more about getting all the performance your sound system
and any given speaker, is capable of giving you. Simple choices often handicap audio potential
performance and if that comes from an educated understanding of what one is giving up, then that is
a reasonable option. But a gasketed window plug takes care of bass passing through the window, and
noise filtering in.


So exactly what are those built-ins, in the counter? Is that a refrigerator that is going to raise your room's
noise floor?


I suspect you will want two intakes and two exhausts. And that also will help with keeping noise down at
the grills.

 

[tjhall04]

You are chipping away at my concerns.


As for hard core audiophile, I'd call it more about getting all the performance your sound system
and any given speaker, is capable of giving you. Simple choices often handicap audio potential
performance and if that comes from an educated understanding of what one is giving up, then that is
a reasonable option. But a gasketed window plug takes care of bass passing through the window, and
noise filtering in.


So exactly what are those built-ins, in the counter? Is that a refrigerator that is going to raise your room's
noise floor?


I suspect you will want two intakes and two exhausts. And that also will help with keeping noise down at
the grills.

Regarding the built-ins, I just used a default sketchup mini bar to get an idea of scale. We would like to get a beverage cooler in there, but I'm thinking of having it on a zwave outlet to simply turn it off when the movie starts, and/or to buy as quiet a unit as possible.

Two intakes/returns are definitely the plan.

Definitely going with gasketed window plugs, really glad you brought those up.

Contractor digs this project, and had some follow up questions for me that I'm hoping someone could help with:
1.) Does it make sense to stagger the double layer of drywall on the ceiling? So put up the first layer on the furring channels as normal, the do a 4x4, green glue, stick it up and screw into furring channel, then do the normal 4x8 to cover the first layer's gaps/seams? Just worried about this greatly increasing the difficulty of the project considering we need to cut for backer boxes for the lights and speakers.
2.) Does "sound proofing" insulation help? He's already going to be using one block as a fire block at the top, however he asked if he should just buy 3 or four blocks to fill the soffits and the ceiling. He said he's getting them at about $70/block.
3.) Rather than doing backer boxes for the lights, would insulated cans work?

Thanks for all the help so far!

 

[Tedd]

I staggered all my drywall seams. All wall and ceiling seams are offset one joist/stud spacing, with a simple
fire coat of mud. All drywall edges were caulked with 40 year silicone caulking, before installing the adjoining sheet
of drywall.


I don't understand how this complicates things (and I did backer boxes)? You would need to cut for backer boxes
no matter what the drywalling pattern is anyways.


Insulation doesn't do a good job sound proofing bass. But what you don't want is resonant cavities, so you fill with
insulation, including the stage (if you don't sand fill), and the riser.


Some people have used insulated cans and they seem to have done the job. But I have no real personal
experience outside backer boxes, which were inexpensive and straight forward to build. Lots of GG drying
time and about a week of 10-15 minutes easy work, here and there. Owning more clamps would have sped
this timeframe up, but not cut down on the minimal "actual" work.

 

[tjhall04]

I staggered all my drywall seams. All wall and ceiling seams are offset one joist/stud spacing, with a simple
fire coat of mud. All drywall edges were caulked with 40 year silicone caulking, before installing the adjoining sheet
of drywall.


I don't understand how this complicates things (and I did backer boxes)? You would need to cut for backer boxes
no matter what the drywalling pattern is anyways.


Insulation doesn't do a good job sound proofing bass. But what you don't want is resonant cavities, so you fill with
insulation, including the stage (if you don't sand fill), and the riser.


Some people have used insulated cans and they seem to have done the job. But I have no real personal
experience outside backer boxes, which were inexpensive and straight forward to build. Lots of GG drying
time and about a week of 10-15 minutes easy work, here and there. Owning more clamps would have sped
this timeframe up, but not cut down on the minimal "actual" work.

Never done this before, so offset it is! Contractor brought this up anywho so it sounds like it'll be fine, he said his drywall crew charges per sheet anyways and he won't charge extra for it.

Regarding backer boxes, actual construction I understand, but it's the getting it to stick on the drywall that confuses me. Soundproofingcompany.com diagrams it and basically has them held in place by the wires, then accoustic caulk, then you put the drywall up and screw the box down to the drywall with screws. I'm wondering how does the box actually stay there (the wires are really enough?), and do you have any tips on how to line them up? Am I just overthinking this?

 

[Tedd]

Here's how I would do about it. 2x2" flange on the backer box, recessed 5/8" of an inch from the edge.
Use the flange to screw drywall screws into, to secure the backer box. The flange would get a bead of silicon
caulk.


Mine are a little more complicated but this design would reflect a few refinements over my 10 year old backer boxes.
I used retrofit 4" spots with a glass trim ring. Instead of the metal box, I would use concrete backer board to line the
MDF box. The electrical wire gets a generous bead of silicone caulk where it enters the backer box.

 

[tjhall04]

Here's how I would do about it. 2x2" flange on the backer box, recessed 5/8" of an inch from the edge.
Use the flange to screw drywall screws into, to secure the backer box. The flange would get a bead of silicon
caulk.


Mine are a little more complicated but this design would reflect a few refinements over my 10 year old backer boxes.
I used retrofit 4" spots with a glass trim ring. Instead of the metal box, I would use concrete backer board to line the
MDF box. The electrical wire gets a generous bead of silicone caulk where it enters the backer box.

Got it, that makes sense and looks relatively easy. Now the question becomes whether I want to actually destroy my ceiling for it since I'd eventually love to put in a night mural and I know I'm already going to have four holes for the height speakers.

 

[Tedd]

Plan ahead and put in large speaker back boxes, and drywall right over them, Make sure you plot the location of those boxes
so if the day comes for the overhead speakers, you know where they are.

I would expect that 4" spots also would impact less on a night mural ceiling. A coat or two of rattle can black on the trim
rings, would go a long way for them to blend in. And maybe you make sure your painted sky pattern misses the speaker boxes
so simple black grilles blend them in.

 

[tjhall04]

Happy Easter!

OK, so some small revisions. My CIC has granted me additional funds, so I can now actually purchase my audio equipment. I decided that I wanted something special, and I will be doing all speakers as "DIY". Air quotes since I will be using kits from DIYSG. I've already bought the subs (2x SI-HT 18's in Stonehenge boxes), however the rest is open for now. I'm thinking of doing 3x Fusion 8 Alchemy Towers for the LCR, and Fusion 6's for surrounds and ceilings. Alternatively I've heard that the Volt 6/8's are better for ceiling Atmos speakers since they're coax (I have no idea). So now I have a couple of questions:

1.) Would going with Fusion + Volt 6's in the ceiling be bad in terms of mixing/matching speakers?
2.) Regardless, for these kits, should I still be installing backer boxes since they're already sealed boxes?
3.) If #3 is yes, then should the boxes be flush, and how exactly do you keep the speaker box inside the backer box?

Additionally, we've decided to add a layer of plywood before the double layer of drywall to allow me to mount projectors/anything else in the future.

Should have the contract signed next week and work to start shortly thereafter, so I'd like to get started on the speakers for the ceiling ASAP.

Thanks in advance!

 

[tjhall04]

Happy Easter!

OK, so some small revisions. My CIC has granted me additional funds, so I can now actually purchase my audio equipment. I decided that I wanted something special, and I will be doing all speakers as "DIY". Air quotes since I will be using kits from DIYSG. I've already bought the subs (2x SI-HT 18's in Stonehenge boxes), however the rest is open for now. I'm thinking of doing 3x Fusion 8 Alchemy Towers for the LCR, and Fusion 6's for surrounds and ceilings. Alternatively I've heard that the Volt 6/8's are better for ceiling Atmos speakers since they're coax (I have no idea). So now I have a couple of questions:

1.) Would going with Fusion + Volt 6's in the ceiling be bad in terms of mixing/matching speakers?
2.) Regardless, for these kits, should I still be installing backer boxes since they're already sealed boxes?
3.) If #3 is yes, then should the boxes be flush, and how exactly do you keep the speaker box inside the backer box?

Additionally, we've decided to add a layer of plywood before the double layer of drywall to allow me to mount projectors/anything else in the future.

Should have the contract signed next week and work to start shortly thereafter, so I'd like to get started on the speakers for the ceiling ASAP.

Thanks in advance!

So a quick bump on the above and also a quick question. If I have staggered and double stud setups for all shared walls, is there any real benefit to doing channel + clips as well? I definitely have them for the ceiling, just wondering as I already have the decoupled aspect factored in by the walls.

Thank you!

 

[tjhall04]

Took a stroll through Craigslist on Friday, lucked out big time:

Stella, meet Bertha:



Also, got my SI-HT 18s, just waiting on the flatpacks to ship from DIYSG. Also officially signed the contract, work should be starting in 3 weeks, permits started already.

 

[eng-399]

Nice rack gotta love the deals on Craigslist