cybergrimes' basement HT

[cybergrimes]

I'm hoping starting a thread will get me motivated to work...

We bought a modular home summer of 2017, had an ICF basement constructed and placed it on top. I've got near 350 sq ft for this dedicated HT. The room is approximately 13' 7" wide by 24' 9" long/deep measuring stud to stud. There's a closet space for media shelving, it's the same width and 4' deep.

There's a few things left to clear out of the room, it kind of got used for storage, but included some pictures to get started.

Seating and screen placement:
My current v1 plan is 100" screen with two rows of seating. 3 seat couch recliners should work in this space. The first row will be 11' from the screen. Behind the first row I want to build up the floor maybe 8" to raise the 2nd row of seats. It'll have to step down again to get into the closet. I had 3 rows of electrical boxes put on the wall for sconce lighting, the first set of lights would line up with the first row of seating in case any light is needed.

Audio:
I'm looking to go with a 7.1.2 or 7.1.4 setup. Surrounds will be wall mounted and I'll position everything towards the first row of seating. I'm apprehensive on the in ceiling speakers, I think I'll need to build some kind of box to dampen them from being too noisy above. For this size room is 2 enough or do I go to 4?

Construction and acoustics:
Right now you can hear anything and everything between upstairs and downstairs, this includes the finished areas. Footfall is pretty loud too. I'm not terribly worried about this because if my wife and I are using the room then most likely nothing is going on upstairs. All the same I do want to attempt some mitigation, I was thinking single layer of drywall on furring channels with Rockwool Safe n Sound in both the walls and ceiling. Eventually the thin vinyl upstairs will be replaced with plank vinyl and maybe some kind of MLV product added in between.

There's some real weak points in the HVAC that I don't know how to address-- the air return in a row of joists connected to my daughters room and dining room above. There's an 18" vent on both sides upstairs, in the basement it's currently just covered by this foil sided cardboard material running over the metal return duct. Any thoughts here?

Wiring and equipment placement:
I plan to place equipment on the back wall with a channel going up into ceiling for the HDMI. I'm looking at projector placement around 20' deep. This will clear all the seating and joists with duct work. It looks like there are plenty of projectors that can do 100" at that distance. I also want to wire the room for both a traditional projector and possible UST at the front. If I double wire the speakers for both locations I shouldn't need any HDMI channel from front to back... just move receiver to front of room with UST if I choose to use one.

and I think that's where I'm at... a long ramble, it helped to write it all down though. I'll start with running speaker wire and then step into next steps. Any feedback if appreciated.

Thanks!

[sonic_debauchery]

Nice. Look at projectorcentral.com for throw distances. 20 feet will do well over a 100 inch screen.

Definitely 4 atmos speakers. There are ways to dampen ceiling speakers....look at gates70 construction thread.

I have 5 vents in my basement. There is no cheap way to dampen them. Think it requires hvac to be moved.

Check out gates 70 construction build he is using furring channels.

[cybergrimes]

Thanks for the info. I've checked Projector Central before and the way I interpret the throw distance calculator it is yes they can do way over 100" but if I keep the zoom dialed down it should keep the image at that size from that distance?

I ordered speaker wire yesterday! and included enough for 4 in ceiling speakers too.
Saturday I'll do a pickup order from Menards for some lumber to start on the platform build.

[cybergrimes]

Started working this weekend!

90% finished with the framing for the platform in back half of room. I under calculated the number of boards I needed... the OSB on top is just to get a feel.
Need to put down some vapor barrier and then fill with the mineral wool. I'll probably run some speaker wire through here to shortcut going around the corners.



Made some decisions about HVAC mitigation. I'm not going to include the HT room into the air return that runs through the joists. I will instead build one of those "dead vents" going through the back closet into the main basement area. I considered raising the corrugated panning up 3" so I could get some insulation below the air return but was concerned about air flow in the joists. Ordered some MLV to line the inside of the joist / around the return vents, hopefully that helps. Also decided to remove one of two the air vents in the room, I'll cap it inside the joist.

Maybe try one of those round duct "muffler/silencer" on the remaining air out duct?

[sonic_debauchery]

Originally Posted by cybergrimes

Thanks for the info. I've checked Projector Central before and the way I interpret the throw distance calculator it is yes they can do way over 100" but if I keep the zoom dialed down it should keep the image at that size from that distance?

I ordered speaker wire yesterday! and included enough for 4 in ceiling speakers too.
Saturday I'll do a pickup order from Menards for some lumber to start on the platform build.

Yes, just make sure the projector you choose has enough zoom!

Nice choice to do 4 atmos speakers.

The theater is really coming along. Can’t wait to see the progress!

[cybergrimes]

Finally back to the HT project. We decided to put it on hold last year expecting to do a different project but lumber prices and contractor availability delayed that so we agreed to finish this room completely!

Before I stopped last year I was able to remove the room side air return and cover it with new thermopan duct sheets and mass loaded vinyl.



Over the past few weeks I ran the speaker wire for the 7.1 surround. I did like I planned with connections going the front and rear of the room in case I want to use an ultra short throw or traditional projector. I still need to run the Atmos ceiling wires and one more ethernet run.

The past week I finished the raised platform at the rear of the room. It should give the second row of seating around a 7" height gain. I've never laid subfloor before and am disappointed in myself for not reading about it first. I think I over simplified it in my head and my work could have been a lot better. I also failed to consider decoupling it from the walls but am hopeful that its mass will stop too much sound transfer going into the main floor. It's made from 2x6 with two layers of OSB and insulated with mineral wool inside. I'll have it covered in carpet and likely some kind of underlayment as well.



This week the resilient clips, hat channels, putty pads and acoustical sealant will be delivered. Before I start with any of that I need to put in boxes for the speaker plates, run wire and create boxes for Atmos speakers and am waiting for electrician to come out and raise boxes for the sconce lighting. It was stubbed in way too low. I'll have him add a ceiling outlet for a projector too.

I've also picked up a trailer full of mineral wool for the walls. Need another load for the ceiling at some point...