New basement construction

[enodog]

Hello folks,first time poster. I have trolled through many post and cannot seem to find an answer to the following question:

New construcion. 16'wide, 23' long, 8 1/2 high.
floor = dricore subfloor over slab http://www.dricore.com/en/eIndex.aspx
ceiling = currently exposed 16" LVL I-beams with rock wool insulation
walls = front and left and right walls are cement block, back wall is two 2x4 stud walls (air gap and double back walls was caused by slight misplacement of the radon vent!)

I am not overly concerned with sound isolation since it is a basement room with 3 exterior walls. Above the theater is a kitchen. Since there is decent rock wool insulation in the ceiling I think the kitchen will be fine. Again I have a limited budget and I want to slowly do all by myself.

1) Do I need to worry about room in a room benefits and sound isolation or can I just focus on sound diffusion and absorption?

2) I would like to install a 6" drop ceiling so that I can get at all my wires etc... and I thought that a drop ceiling could be made to look nice. I have read that the tiles can rattle. I like loud! Can a decent qulaity Sonex tile or equivalent be installed rattle free? Should I jut put in some conduit and have it sheet rocked? If I have it sheet-rocked and use a nice theater plush carpet on the floor will this be okay? Perhaps careful placement of diffusion and absorption on the ceiling will be adequate?

Any help would be great.

Will

 

[bpape]

Wow - where to start.....

Isolation is just as much ore more about keeping sound OUT of the theater than it is keeping sound from getting out. The quieter the room is to start with, the more apparent dynamic range you'll have and the more microdynamics you'll get. Below a kitchen with people walking on hard floors, water pipes running, and dishwasher motors running is one of the noisier places in the house.

Treating the absorbtion/diffusion in the room is addressing internal acoustics where room in a room is an isolation technique and incompatible with a drop ceiling. It's not one or the other it's both. Isolation to have a low noise floor and internal treatment to assist with decay times and frequency response.

Also, while a drop ceiling is very nice and conventient, it will never give you good isolation value. On the positive side, stuffing the cavities above with insulation allows the entire ceiling to function somewhat as a broadband bass absorber.

Bryan

 

[Bryce_H]

Will - my theater is almost exactly like yours (except it is under the formal dining room, office, and front entryway). My post construction dimensions are 15'6" X 23' X 7'6". I constructed 2X4 walls with sheetrock on the three concrete walls (insulated) and a 2X4 staggered stud wall in the back (on a 2X8 foot). I have an I-beam that runs across the HT about 1/2 back from the screen - so I dropped the ceiling in the front 1/2 of the HT to hide the I-beam. However, my drop ceiling is drywalled (bought drywall mountable drop ceiling components). I haven't done it yet, but acoustic treatments are next for me.

I would echo (no pun intented) Bryan's comments.

To address your desire to "get at your wires" I ran 7 2.5" conduits to the 7 speaker locations. This allows me to swap out cables and run additional cables if I ever needed.

 

[enodog]

Thanks to both of you for your comments. I guess what I am reading is that if I spend the money for sound isolation I will end up with a room that will be easier to balance with acoustic treatment and will sound better since escaping sound is wasted sound. So, even though I do not care about the adjacent exterior spaces to my home theater hearing what is going on in the theater room, I should be concerned about the wasted energy.

If the above is true then I would wonder about the following. If 3 of my 4 walls are exterior 8" cement block, will the earth beyond them be a sufficient sound tomb? If so, I can save money on acoutically isolating those three walls and simply spend money on my rear wall (the only non-exterior wall) and floating the floor and floating a sheetrocked ceiling using an isolation hanging system.

This morning I have been on the phone with a company (Kinetics Noise Control) that will sell me a room isolation kit. Seems pretty convenient to get them to simply whip me up a kit and send it out. I was wondering if anyone had dealth with them or Acoustical Solutions or perhaps any other people that would sell kits to a DIYer and provide basic over the phone help. I am pretty handy and can build walls, install flooring etc... Best of all I have my workshop in the basement near to the theater room!

Lastly, I do not think I will mess with a drop ceiling. They seem a tad expensive, potentially rattlesome, more frustrating to install then the floating sheetrock and, like you, I can easily run the conduit to the various room locations.

 

[jaxvon]

Thanks to both of you for your comments. I guess what I am reading is that if I spend the money for sound isolation I will end up with a room that will be easier to balance with acoustic treatment and will sound better since escaping sound is wasted sound. So, even though I do not care about the adjacent exterior spaces to my home theater hearing what is going on in the theater room, I should be concerned about the wasted energy.

Just a quick note...

You won't be saving any energy with acoustical treatments and sound proofing. Acoustical treatments in the room and in the walls (in-wall stuff is only for bass) is designed to flatten the frequency response and stop other acoustical anomalies like excess reverberation or sound being reflected into places it shouldn't be. Sound proofing is, as discussed previously, designed to keep sound from leaving the theater and also to prevent noise from entering. If you're serious about this, you should aim for an ambient noise level (with everything running, including the HVAC system) of 20dB. In either case, when you're using a material that absorbs sound, like mineral wool, it is converting the mechanical energy of the sound waves into heat. The result is that you're not saving any energy, but you are improving the listening conditions in the room, so it's still justifiable. It's quite achievable provided you take care to do things right the first time. Great ways to control noise in the listening/theater room are:

• Baffling and isolation system for your HVAC installtion
• Mechanical isolation of the theater room structure from the main house structure
• Locate your equipment stack in another room that has no sound bleeding into the theater room
• Good soundproofing in the walls around the theater
• Hush box for a projector (if you opt for one)

 

[bpape]

I think you missed my point. The idea of the isolation is to keep it quieter INSIDE the room and prevent noises from outside from getting in and raising the ambient noise floor. Even though your 3 walls are concrete and dirt, sound can flank around through a weak wall structure and up through the floor into the rest of the house (though this may not be your concern as you stated).

I have no idea what Kinetics is proposing so I can't comment on what the package is, if it's a viable, reasonably priced solution, etc. Personally, in your case, if sound leaking OUT isn't a concern, I'd do the following:

- RSIC-1 clips on the ceiling with hat channel.
- Double drywall with Green Glue on walls and ceiling
- No need to float a floor though you can if you want.
- Seal under the wall/floor intersection with sill seal and caulk the edges.
- Fully insulate all cavities (walls backed up to concrete, interior walls, and ceiling cavity above)

This is a reasonably priced way to get very good isolation, a very predictable starting point for treating the interior of the room, etc. - without giving up a ton of space or money.

Bryan

 

[Bryce_H]

That is the way I constructed my basement theater, although I RSIC-1 clipped the whole room with hat channel. For the drop ceiling I used RSIC-DC04X2 clips to attach the suspension wire. I only used a single layer of drywall. I did build a subfloor (which saved my butt when our basement flooded) on top of U-boats. The ceiling has a double layer of insulation, the walls have a single layer of insulation, and the riser is stuffed with insulation. I have the conduit for the hush box in place, but have not built it yet. Here are pics of my theater. Did all the work myself except for HVAC, plumbing, and the drywall. It started as a bare concrete room.

 

[Adam]

Bryce, that room looks great!

 

[enodog]

I received a proposal from an acoustic company today. This proposal is designed to allow me to create an acoustically ready floating room. I attached a pdf of my basement/theater area but the quality is lousy. Walls are mostly 8" block wall with 2"x4" (laid on side)pressure treated firring with styrofoam insulation. The sheetrocker will rock and tape and smooth finish the walls over the studs . The ceiling has rock wool laid up into the joists (the joist are 16" tall so there is still lots of room for other things in these joists. The resultant width will be 16' and the length is 22'. The height from slab to joist bottoms is 8'8". I was going to follow the mfr instructions and double sheetrock the isolated ceiling, float the floor with 2 layers of 3/4" plywood (using the floating loor foam) and use the rest of the materials listed below.


Since I am new to this I am not sold on any particular company but i am hoping to get some feedback before I move forward. My builder is willing to install these "rough-in" items along with my supervision but i will hae to order and have the items in site with 3-4 weeks. I realize that there are other companies and perhaps other solutions. I know that I may not have the time to research all possibilities but I am hoping that some of you may be able to keep me fro making any big mistakes!


RIM Floating Floor 4’ x 50’ x 1’’ (2 rolls)
PIB Isolation Board ¾" x 2 ½" x 80 Linear feet
KIP Pads 2" x 2" x 1" (74 pieces)
Isomax Clips (Walls/ Ceiling) 1 1/8" x 1" x 3 15/16" (258 pieces)
Barrier Tape 2" x 180’ (3 Rolls)
Loaded Vinyl Barrier 54" x 60’ (5 Rolls)
Acoustical Caulk 10.3 oz cartridge 1 case (24 tubes)
Duct Silencer 13"(w) X 9"(h) X 60" x 6’’ duct (2 units)
KNC Acoustical Pre-Hung Door 36" x 80" (1 door)

 

[bpape]

Well, you've gone from basically no isolation to a serious isolation project - even an acoustical door? That's pretty hardcore. I think that a good quality exterior solid core door will do 90% of the same job for a lot less money. Also, IMO, Green Glue is a superior solution for less money between layers of drywall over the vinyl rolls.

Lastly, unless I'm missing something, I'm not seeing an equivalent to a PAC DC-04 clip to isolate the top of the stud walls from the joists above.

Bryan

 

[enodog]

Bryan,

Thanks for the advice on the green stuff versus the vinyl roll. The vinyl is definitely pricey and I have read good things about the green stuff. I know it is a big jump from no isolation to complete isolation but it seems as if I have the construciton crew willing to build the walls and a sheet rock crew that will do the sheet rock. The money is an issue but I am willing to postpone buying a projector for 1 year in order to have a theater room that is acoustically quiet. Even though I am a novice I figure that $8k-$9k invested now will pay off some point down the road when I learn to appreciate it.

At this moment I KNOW I love home theater and home automation as it is my hobby. I have decent equipment that has always sounded decent in other multi-purpose rooms. Since getting married I have had no theater room for 7 years. My 7 year itch is the the theater room and I just figured on doing all that I can at each step to make it great. If I had ignored room construction I would have a projector this year and could start enjoying it by Christmas. With a great sounding room I have put off using the room for 1 year but at least in the future I can only have isues with equipment purchases/compatability and placement and not more fundamental issues of room acoustics. It also buys me another year to enjoy learning about acoustics!