[bbieger]

Well after several year of dreaming about a HT and a steady outflow of cash acquiring nice AV equipment I am ready to take the plunge and convert my beloved basement shop into a home theater/ "go down in the basement and get of my hair room" for the two children. :wits-end:

I do have a decent knowledge base from forum trolling and completing quite a bit of remodeling and construction work over the years. That said, there are still a myriad of questions circling around in my head about various things. So, I'll guess I'll start with where I am at now and lob a few questions out there. I just started last week to get the basement ready for refinishing.. Like installing a vapor barrier, digging out spot for egress window in the back corner, moving ventilation ducts and cold air returns to eliminate ugly soffits.. Basically the dirty work.

The thought was to have one half of the room for theater and game playing and the back half for socializing, kid playing, etc.

The finished basement space is currently planned to be 16' wide and 28' long with a ceiling height that is rather low..I want to say it is going to end up being 7'. Is this dimension a nightmare for sound because it is divisible by a common denominator?

I am framing in 2x4 walls approximately 1/2" inside the concrete walls with- R13 insulation. In an attempt to decouple these walls I wanted them to be attached to the concrete wall and the sill plate only instead of the first floor joists. I figured that the sill plate has quite a bit of mass and dampening..after all, its an old growth fir 6x6 and it has a whole house sitting on it. (Is this going to be sufficient?--How much better would isolation clips attached tot he foundation walls work?)

My thought for the ceiling is two layers of 5/8 with GG. GG on all the joists before installation. I am also going to either install fiberglass batts in the joists bays (likely) or blow in cellulose after the drywall is up (less likely). (I would really like to be able to play my SVS sub above wife listening levels without shaking the whole house). I can afford to loose ceiling height so clips and track are out. Flooring will be Vapor barrier, T&G plywood, padding and carpet.

For lighting I am thinking can lights, a sconce or two and rope lighting inside small crown molding.

Seating will not likely be "real" theater seating but simply a wrap around couch.

My audio gear consists of :

Polk RTI 8 mains, Polk Csi A4 center, umm forgot the surround models..they are small polks. Onkyo Sr607 receiver, SVS Pc-12NSD subwoofer---(moo awesome BTW), samsung blue ray, xbox 360, Hd cable box. blah blah blah.

A couple questions.. Is a projector suitable for everyday viewing of TV? WE don't watch tons of TV but wonder if the big screen is fatiguing? Does it have to be absolutely dark to get a decent picture? It would be nice to have some lights on for the kids to play in one half of the room and me watch some TV. Perhaps I should build a divider wall similar to..http://www.hometheatershack.com/for...nstruction/15304-new-theater-suggestions.html

Do the reasonably priced projectors (around $1,000) in my case provide high quality pictures? I'm looking for something on par to my samsung LCD.

Would love to hear any comments or suggestions... Especially about my short ceiling height. Would like to go with a 100" screen. I'm looking to build something really nice..as that is just how I roll but I am also trying to keep things within a reasonable budget.

Funny that I just spent the winter months building this media cabinet... and now I'll probably but all my AV gear in a built in . siggghhhhh Anybody want a custom built bubinga and curly maple media cabinet?

 

[Ted White]

I am framing in 2x4 walls approximately 1/2" inside the concrete walls with- R13 insulation. In an attempt to decouple these walls I wanted them to be attached to the concrete wall and the sill plate only instead of the first floor joists.

Spacing in an inch or so is good. Connect to the slab. Connect to the joists. Fill with R13. I'm more concerned with your comment that you connected this wall to the concrete. You mean the top plate of the new framed wall is conected to the concrete? That would be OK

I figured that the sill plate has quite a bit of mass and dampening..after all, its an old growth fir 6x6 and it has a whole house sitting on it. (Is this going to be sufficient?--How much better would isolation clips attached tot he foundation walls work?)

OK so maybe you connected the top plate of your new wall to that old sill plate? Is that the only connection to that foundation wall? All the studs are non-contact with the foundation wall?

My thought for the ceiling is two layers of 5/8 with GG. GG on all the joists before installation.

You'd never add Green Glue to the edge of a stud or joist. Only in between sheets of drywall or plywood, etc. Also, I realize you have a low ceiling, but some element of decoupling of that ceiling drywall would certainly help with isolation. There are methods to attach clips and channel somewhat recessed in the joists that drop the drywall attachment point down only 1/2"

I am also going to either install fiberglass batts in the joists bays (likely) or blow in cellulose after the drywall is up (less likely).

R19 fiberglass would be the best and safest

For lighting I am thinking can lights, a sconce or two and rope lighting inside small crown molding.

Put holes in your ceiling? Much more effort to isolate now. Can you consider track and sconce only?
QUOTE]

Thanks

 

[bbieger]

Thanks for the comments Jeff. Just to clarify, only the new top plate of my wall will be connected to the old sill plate via 90 degree brackets. Top plate = old sill, bottom plate bolted to foundation (floor).

I had read that you can apply green glue to studs in lieu of tape... http://www.soundisolationstore.com/research-how-to-apply-green-glue

In terms of dealing with the can lights, I was going to build and install MDF boxes to install the can lights in, not really stoked about building all those MDF boxes but whatever.. cheaper than buying them..http://www.soundisolationstore.com/quietbox-recessed-light-soundproofing.html

 

[bpape]

A $1k pj isn't even going to come close to a decent LCD - sorry. Big pic only goes so far if the quality is variable.

Cans penetrating the ceiling defeat your isolation attempts unless you box them in. Soffits are there for a reason (lighting, hvac, wiring, etc.) but AFTER you drywall the room.


The 7' ceiling height is an issue regardless of how it relates to the other dimensions of the room. That puts the 1/2 point at 42". General rule of thumb seated ear height is 40-42" so you're right in a huge modal problem for the height dimension.

Bryan

 

[Ted White]

If you have interest in building a box, this may be of interest: http://www.soundproofingcompany.com/manual/sim_backer_box_installation_guide/ Bryan is right about their necessity.

Thanks for the clarification on your wall. Assuming the 1/2" or better distance from the foundation, that wall would be considered decoupled. The foundation and the new wall drywall comprise a "double leaf system." Your construction allows the inner leaf to move independently.

 

[bbieger]

Ok, sounds like the boxs are going to be a neccesity. Trying to avoid soffits due to height. I do have a question about the walls though.. Is the 1/2" offset from the wall more of an accoustical preference or sound transmition reduction method? Also, should I use 5/8 rock for the walls as well? That stuff is a bear to hang but if it going to sound better so be it. I'm just unsure of it's neccesity on a decoupled wall.
Thanks a bunch! Going to fire up the framing hammer tonight.


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[Ted White]

Soffits are great for ventilation mufflers. You'll want to consider getting air in and out without compromising your sound isolation.

The 1/2" offset is for isolation. As I mentioned, the gap will allow that drywall panel to move independently. The leaves are decoupled, and this will significantly lower that partition's low frequency resonance point, allowing you to contain low frequencies much better.

Similarly, the mass of the 5/8" drywall will move that low frequency resonance point down even farther. The presence of insulation as well as the cavity depth also contribute to progressively marching that LF resonance point down.

On decoupled framing, mass and insulation provide an even bigger payback than they would on a coupled frame system.

 

[MatrixDweller]

For lighting I am thinking can lights, a sconce or two and rope lighting inside small crown molding.

Put holes in your ceiling? Much more effort to isolate now. Can you consider track and sconce only?

With 7' ceiling track lighting (which could be very warm) would bump heads. You can get can lights that are air tight and I/C rated. The I/C rating is important because if it doesn't have that then nothing can touch the can inside the ceiling as it will be hot (in temperature). I/C can have insulation touching the can and there isn't the danger of fire or over heating lights. Scones are a viable option too, but in a 16' wide room they wouldn't be ideal for whole room lighting.

The holes in the ceiling made by the pot lights will effect the soundproofing. Yes ideally they are a no no for perfect results. I do have them in my basement and almost no sound comes up through the floor. I used air tight I/C rated pot lights and have Rocksul safe n sound insulation above and all around them.

 

[bbieger]

Hmmm good results with no boxes? Could one dynomat the cans and achieve decent results? While I want decent results I'm not building a rcording studio....
I'll ponder it as I descend into the basement to make sawdust and noise

 

[bpape]

Decent - maybe. Good - no. Remember that you get ONE shot at doing this. There's no going back later and changing if you change your mind (without ripping the whole room down.) It's not a big deal to do the boxes and eliminate the issue rather than trying to fix a problem

Bryan

 

[Ted White]

As a rule ceiling cans aren't at all recommended without the backer box. Again Bryan is right on the money. You have one shot to get this right. You want Mass. Ceiling cans have no mass. Some rubber solutions have a bit of mass. But a simple field assembled box has a lot of mass.
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[MatrixDweller]

While I want decent results I'm not building a rcording studio....
I'll ponder it as I descend into the basement to make sawdust and noise

Boxes shouldn't be too hard to build and will help.

I hear what you're saying about not building a recording studio. Even if you take modest measures to soundproof you'll be happy with the results rather than having no soundproofing at all.

If I had of done the research before I started building I would have built boxes around my cans. I'm still happy with the results without them however.

 

[bbieger]

Yeah the one shot at it really makes sense to me. I'll build the boxes. I have to sit down and figure out all the lighting and cable runs as I'll likely have it all framed up by the end of the weekend. I'll submit some pics and a floor plan for some advice. Especially on rack placement, lights, and espcecialy where shoul I run conduit for the projector that I have no money for
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[Ted White]

Holler if you have questions about the framing. The framing is critical, since this is what decouples the system.

I'd once again encourage you to consider decoupling the ceiling. If you want ideas / images. let us know

 

[bbieger]

Ok, so here is a layout that I sketched. Man this room is long and skinny Of well, sans moving the chimney it has to stay skinny. (no, I'm not going to move the chimney...but I did think about getting rid of it :bigsmile:

So today I am framing the egress windw and building a window well. I'll post some pics later. Couple questions about the layout.

What do you think about the can light location?
Also, the position of the media cabinet seems less than ideal. It will be built into the wall but it seems too close to the tv/screen?
Also, is there a way to approximate where a projector would go so I can run the cables now.

Cables have come a long way so I am thinking:
1. HDMI from media cab to TV and media cab to projector.
2. Ethernet, Coaxial for comcast,
3. Speaker wires for 5.1 (is 7.1 REALLY all of that? I've heard both sides)

Am I missing cable runs that I should put in?

Thanks for the help guys!! Your input provides inspiration to keep up the perspiration!!

 

[spartanstew]

Also, the position of the media cabinet seems less than ideal. It will be built into the wall but it seems too close to the tv/screen?

It depends upon the user. Some like the equipment to be invisible, so they'll place it in the rear of the room, or in another room altogether (so lights aren't distracting). I prefer the location that you currently have it in. The lights aren't noticeable (IMO) when looking at the display and it allows me to glance over at the equipment for information I might want (volume level, audio track, time left on movie, etc.).

Also, is there a way to approximate where a projector would go so I can run the cables now.

It's really dependent upon the projector (and throw), so you won't really know until you decide upon a projector. You could always run line from the media cabinet to the second can light (from the front) and then from there all the way to the back wall (basically running alongside the third green can light and the two blue ones). When you decide on a projector, you can replace any of those cans with a projector mount and pull the line through. The bigger issue is where to put an outlet for the projector. You could always put a couple of outlets and the different ceiling positions.

Cables have come a long way so I am thinking:
1. HDMI from media cab to TV and media cab to projector.
2. Ethernet, Coaxial for comcast,
3. Speaker wires for 5.1 (is 7.1 REALLY all of that? I've heard both sides)

You should also run at least 2" conduit from the media cabinet to the TV and projector area just in case.

With a room that deep, there's definitely the option for 7.1. I'd at least run the speaker wire for it on the back wall, just in case.

 

[bpape]

If it were me, and only wanting one sectional in there, I'd very seriously consider shortening the room. This is for several reasons.

Proper seating position acoustically will require the screen to be relatively large. With the room only being a bit under 11' wide, where do you put your speakers unless you do an AT screen?

General rule of thumb is that no one dimension is no more than 2.5' any other dimension. The length is over 2.5x the width and over 3x the height.

Bryan

 

[bbieger]

If it were me, and only wanting one sectional in there, I'd very seriously consider shortening the room. This is for several reasons.

Proper seating position acoustically will require the screen to be relatively large. With the room only being a bit under 11' wide, where do you put your speakers unless you do an AT screen?

General rule of thumb is that no one dimension is no more than 2.5' any other dimension. The length is over 2.5x the width and over 3x the height.

Bryan

yeah, I'm curious what you think the proper spacing would be for the front main speakers?

I thought about shortening the room but I need the run around room for the kids..

 

[bpape]

I a room that length, optimal distance to avoid modal issues from the length (lowest and hardest to deal with) is between 8'9" from either the front or rear wall.

From the front that would likely dictate a larger TV or small PJ screen. Even so, that leaves maybe 1.5' outside the screen on both sides so the speakers are essentially against the wall.

The long way, just not going to get proper viewing angles.

Could you wall off a portion of the back of the room and have a door that could be left open for the kids and closed when watching movies/listening to music seriously?

Just thinking out loud.

Bryan

 

[MatrixDweller]

You may want to place the light circuits in three banks, front, center and rear. Rather than sides, middle and rear. Have the center bank over your seating so that it can be on slightly and the front and rear can be totally off. That will give you better screen viewing dynamics and allow you to see your remote and/or popcorn.

My room is about 10' wide and long like yours. I have two rows of lighting on one dimmable circuit (wish I had of done front and back lighting). My ceiling is 7'-6" high and the lights are spaced about 4' apart on center. With the pot lights at full the room is very bright even though the baffles are black and the bulbs are only 50W (can take up to 75W). I rarely use my sconces and they are basically just ornamental.

I found this guide fairly helpful. You probably don't need three rows, two will be more than adequate unless you plan on using narrow beam halogen lights. If you want more lights then task lighting or wall washers are always nice.

You can check out my build thread here: http://www.hometheatershack.com/for...nstruction/6932-diy-home-theater-project.html

Another tip with the lighting and dimmers. Only buy the PAR type bulbs. BR type bulbs tend to hum when dimmed (I found out the hard way). For Edison type bulbs on a dimmer, ceiling fan or appliance bulbs can reduce the hum. I had a thread on that also.

As for 7.1: You might as well either run conduit or wire for it while the walls aren't closed. It's a lot easier now then later. As to the best spot for the rear channels someone else might answer that better. My guess would be near your rear egress window, on stands behind your sectional or hanging from the ceiling.