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Discussion Starter #1
I made the first purchase for my theater so I suppose that means it’s time to start my build thread.

Four years ago we built our house and at that time we had to cut the theater from our original plans due to cost. That was a blessing in disguise because it gave me plenty of time to do more research (mostly here on the AVS forums) and come up with a bigger, better theater. We just got the new plans from our original architect. It’s bigger and has an equipment closet plus a bonus room above the theater.

Goals:
  • A “better than commercial cinema experience”.
  • Comfortable seating for my family of 5 plus a few friends and adequate seating for the occasional larger get-togethers.
  • A low noise floor plus be able to watch movies at night at an appropriate level without disturbing the kids sleeping upstairs.
  • Fit with the modern aesthetic of the rest of the house.
The name - Dawkness. It’s not a misspelling, but what my middle kid called the color black when she was younger. The Dawkness Theater.

Dimensions: 17.6’ x 26’ x 11.5’






I’ve spec’d that the slab in the theater be dropped to 18” below the current floor so there’s a level entry onto the riser.
Two rows of seating plus a bar squeezed into the back. I think I have the seating worked out now to fit the bar but it's tight.

Eyes and ears: Scope & Atmos 7.1.4

Soundproofing:
  • Double-stud left wall, clips & channel on remaining walls & ceiling.
  • Double ⅝ drywall (maybe OSB first layer) with Green Glue.
  • Horse stall mats & OSB over slab.
  • Floor above to use Soundproofing Company solution 5 (multiple subfloor layers with Green Glue and rubber mat).
  • Doors: fortunately I can put in 2 doors and have a bit of a “micro-lobby”. The rest of the house uses EZY-Jamb flush door jambs which are mudded into the drywall so I’ll have to figure out how to incorporate those. Doors will likely be 1 ¾ exterior solid doors, maybe a layer of MDF & GG. Seals & automatic door bottoms.
Equipment:
  • Marantz 7704/5 pre/pro
  • MiniDSP 10x10 (to matrix the 2 sets of side surrounds and do sub EQ)
  • Crown XLS amps all around.
  • Whatever JVC projector I can get for ~$4k
  • DIYSG HTM speakers for LCR and Volt surrounds although I do have a full 7 channel set of old Athena speakers including AS-F1 mains that might do temporary duty at first.
  • DIY UM18-22 subs 2 up front, 2 in back; Full Marty-style cabinets.
Acoustic treatments:
Following Anthony Grimani's recommendation of 20% absorption and 25% diffusion. Most likely all DIY treatments as commercial products are expensive for what they are in my opinion. I'll probably build QRD, PRD, and poly diffusers. Absorption panels will probably be Roxul Comfortboard or Safe-n-sound since I can order that through Lowe's. I'm going to try to take an empirical approach to the treatments - measure, add, measure, repeat. I could have a professional design done, but where's the fun in that? ;)

Furnishings:
Not interested in the purpose-built home theater seating out there from a purely aesthetic standpoint. I know they can be comfy and many theater owners love them, but they’re a big nope for me and my wife.
Row 1 4 West Elm Spencer recliners
Row 2 4 West Elm Enzo power reclining couch.

I’ve sat in both of these and they are quite nice.

Alright, if you’re with me this far you want to know what the first purchase was.
https://www.bludot.com/knicker-barstool-5-1-outlet.html

It was bar stools so I’m kind of committed to doing the 3rd row bar. Blu Dot had a great deal on these so my wife and I pulled the trigger. After opening them and inspecting for damage, back in the box they went and I put them in storage. I have to say the cost is worth it on these. They’re extremely well made out of hardwood and very comfy.

That leads into one of the challenges that I know my fellow AVSers can help me with. 26’ of length doesn’t allow a lot of room for 2 rows, a bar, and big subwoofer cabinets. I want to use balancing subs front and rear placed at ¼ of the width in from the side walls to smooth out room modes. The solution I’m contemplating now is laying the sub cabinets down on their backs inside the riser firing upwards. Thoughts?

I’m also open to screen recommendations. I’m still trying to figure out what viewing angle I prefer. Requirements are acoustically transparent and 2.35. I’ll probably also need a little gain if I want to be able to show HDR with a reasonably priced JVC. The wide range of manufacturers and prices is intimidating. I'm willing to spend a little more for a good value so I don't have to upgrade for a long time if ever.

I'm at a critical phase here where I'm about to start talking to builders so I appreciate any suggestions.
 

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Looks Awesome man!! You've put A LOT of thought into this. Keep us up to date!!
 

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Subs in the riser would be one way to save space. You could also possibly build the sub cabinets into the bar. There’s a beautiful example of this somewhere and I can’t find it right now. He built a bunch of mid bass modules as vertical columns with a large chamber of sub woofage behind it and made it all look like a nice base cabinet for his bar behind the row of seating.
 

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Love the detail of the specs, be sure your framer knows to erect the screen wall framing after the room is drywalled, I think every contractor I've worked with conveniently misses that design element even though it is clear in the plans, because they don't want to bring the framers back for a second visit.


Do you have HVAC and electrical plans for the space?
 

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My theater is also ~26' (25'8" if I remember correctly) in length and I have 2 rows of seats, a bar, and an acoustically transparent screen. It all fits with no problem. I could (should) have went a bit deeper on my space between my screen and wall (I think I used 22") because after adding sound treatments it was a little shallower than I would have liked for the sub-woofers. All I did to fix it was to build my diy sub-woofer cabinets taller and wider to compensate for being on the shallow side. Looking back I easily had room to go 28-30". I am using a 124" wide screen and my front rows eyeballs are ~120" from the screen. The back edge of my bar-top is almost 5' from the door so you should have no problem especially with a side entrance.
 

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Discussion Starter #7
Thanks for the replies everyone.
@sassuki I hadn't considered using the bar as a sub enclosure. I'll have to marinate on that a bit. I feel like 12 cubic foot enclosures for Ultimax 18s wouldn't leave any leg room but maybe smaller drivers would work.
@BIGmouthinDC Noted on the screen wall. I plan on going over your contractor notes with potential builders. The architect didn't do an HVAC plan nor an electrical plan, but here's what I'm thinking:

I have a good grip on how to keep things quiet with dead vents, slot diffusers, and keeping the registers flowing less than 250 feet/min. I’m thinking a 2-zone ducted mini-split is probably called for; 1 zone for the theater and the second for the bonus room above. I plan to ventilate the theater exchanging air with the rest of the house, but what I’m not sure of is the number of air changes per hour required. I’ve seen as high as 8-10 recommended. Is that necessary?

The layout of the HVAC is a little challenging as well. Due to the interior design plans I have for the theater, I don’t want soffits running the length of the room. Soffits are ok for the front and rear walls though. So that means the bulk of the ductwork needs to be in the ceiling joists. The architect spec’d TJI ceiling joists that are 11 ⅞” tall on 16” centers. The largest hole allowed in those is 8”. Based on online calculators I've determined that at least for the HVAC side, I need 400 CFM which means 2 8" ducts and to keep the vents quiet I calculate 2 square feet of register area. I hesitate to make too many plans here without talking to an HVAC tech.

For the electrical, here's my thinking:
  • 3 20 amp outlets for the rack
  • Power inlet for the projector UPS
  • Surface-mounted outlets and light fixtures in the theater
  • Riser outlets for recliners
  • Riser outlets for the bar with USB charging ports
  • Outlets in the face of the riser for the front row
  • Insteon switches (whole house is already Insteon)
  • RGB LED strips will be 24 volt, DMX controlled
My main panel for the house is full, so a new sub-panel will be needed in the equipment closet.
@brazensol that's good news on being able to fit the bar. I laid it out in SketchUp (AKA fought with it until I got 75% of what I want) and it looks ok. My first row is really close to the midpoint of the room, so I may scoot it forward a little.
 

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It looks ok but have you explored the audio side of those choices?

You now have a large reflective surface with the overhead channels, and now you have a large box blocking the rear surround channels, which shouldn't be
raised with an ATMOS setup. You also have a reflective box backing second row heads. and the overflow nature of the third row, also now has the rear
surround channels right on top of seating. Lots of issues being created with that third row, that maybe you want to explore. There's also the cost factor of
that third row, which maybe is better spent elsewhere, if you don't absolutely need all those seats and they won't be filled most of the time. You could simply drag in
some seats and maybe some of BigmouthinDC's BigA$$ steps would offer up space for some occasional use seats, as an audio compromised seating alternative?

I'm not a fan of soffits either, if one can avoid them. There's that storage space running down the side wall that might be rather convenient.

Ever cue up a movie for guests? I see you built in a little bit of space in the entry. Ever consider making that a horizontal space instead of a vertical space?
You could bring a narrow vertical rack like a Middle Atlantic Slim 5 right by the door, and have screen sight lines. The storage space door could be a hidden, and
you could work in a simple feature wall and perhaps a movie poster lightbox or two, or a digital movie poster light box, with the horizontal elongated entry.

I wouldn't count too much on HVAC people understanding exactly what you are after. That comes up in most home theater design seminars I have taken, where
the designer states the noise level at the vent permissible and if the HVAC guys screw it up, it's on their dime to get it fixed and meet the contractual specifications.

That slim closet also has potential for inexpensive media shelving, if you have a large collection.

Why 20A circuits? Is there any 20A gear?

What's stopping you from multiple smaller HVAC runs, if a single 8" run isn't going to cut it?

I see you have but one set of steps, is this an omission or are you taking the seating right over to the wall?

Your front row seated ears are pretty much dead center on the length of the room, which is a big issue. Another reason why I question the third row's usefulness.
Along with the shallow AT space, which could be viewed as some flex space to nail the audio layout down, and then work the screen viewing angles and size.
Another luxury item in higher end rooms, is space, and that gives one separation from surround speakers.

More air changes aren't a bad thing, but the number I have heard is an absolute minimum of 3.5 air changes hour, in design seminars.

Anyways, just a bunch of thoughts for consideration...
 

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Discussion Starter #9
Thanks for the insights Tedd. As usual, you loaded up your post with good info.

It looks ok but have you explored the audio side of those choices?
I was a little concerned about the rear surrounds being blocked by the bar, but it hadn't occurred to me that it would cause some bad reflections from the height channels. You're right, they're just occasional seats for when we have a large group over or we want to maybe have a meal in there. All this has me upping the ante to consider doing some kind of hide-away bar that disappears into the riser. I've never seen that before.

I'm not a fan of soffits either, if one can avoid them. There's that storage space running down the side wall that might be rather convenient.
Good idea. I'll try to use that area as much as possible for ductwork.

Ever cue up a movie for guests? I see you built in a little bit of space in the entry. Ever consider making that a horizontal space instead of a vertical space?
You could bring a narrow vertical rack like a Middle Atlantic Slim 5 right by the door, and have screen sight lines. The storage space door could be a hidden, and
you could work in a simple feature wall and perhaps a movie poster lightbox or two, or a digital movie poster light box, with the horizontal elongated entry.
I call that my micro-lobby - a place for snacks, maybe a microwave. My plan is to put the rack inside the storage area. Sources that I'll need access to like Blu-ray player and Nvidia Shield will be located in the room.

I wouldn't count too much on HVAC people understanding exactly what you are after. That comes up in most home theater design seminars I have taken, where
the designer states the noise level at the vent permissible and if the HVAC guys screw it up, it's on their dime to get it fixed and meet the contractual specifications.
I was afraid of that.

Why 20A circuits? Is there any 20A gear?
Max combined amperage draw on the subwoofer amps alone is 24 amps. I calculated total draw from all the equipment in the rack plus projector to be 55 amps. Of course all equipment isn't going to be at peak draw ever, but 3 20 amp circuits is easy to do. The entire existing house is wired with 12 gauge wire so it seems appropriate to do 3 20 amp receptacles from a new subpanel.

What's stopping you from multiple smaller HVAC runs, if a single 8" run isn't going to cut it?
It'll have to be that or 1 10" if I don't have to cross joists.

I see you have but one set of steps, is this an omission or are you taking the seating right over to the wall?
That's just the way the architect drew it. There will be steps on both sides, seating centered.

Your front row seated ears are pretty much dead center on the length of the room, which is a big issue. Another reason why I question the third row's usefulness.
Along with the shallow AT space, which could be viewed as some flex space to nail the audio layout down, and then work the screen viewing angles and size.
Another luxury item in higher end rooms, is space, and that gives one separation from surround speakers.
Yeah, I called out the first row position as a problem. I've worked out the seating in terms of percentage of the length from the front wall as 53%, 77%, 90% for rows 1, 2, and 3 respectively. I think the front row needs to either be back at 55% or forward at 45%. I have the front of the screen wall at 20" from the front wall. Should I go deeper?
 

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I've got a bar and haven't noticed any strange audio problems/issues with it but I have not run any measurements either. Ignorance may be bliss here!
 

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Discussion Starter #11 (Edited)
Brief update. I met with a builder today which has me excited to know that we're moving forward a little in the process but also dreading how high the bid will be. :eek:

This is a pretty high end design-build firm so they do fantastic work. I handed over some notes based on Jeff Parkinson's contractor's notes for high performance theaters. He didn't balk at anything on those 2.5 pages so that's a good sign.

They do have experience with clips and channel, soundproofing, etc. He dug up a sample of Blue Ridge Soundstop board as a potential soundproofing wall material. I wasn't impressed. It's very lightweight. Being a recycled product, I think it's more useful for getting LEED points than soundproofing theaters. It might help reduce some noise between rooms for instance, but there's not enough mass to be effective at low frequencies. They do publish testing data and the STC ratings aren't as good as the basic double drywall and green glue systems.
IMG_20190312_093837.jpg

I feel like this will be a good builder to work with, but it's not going to be cheap!
 

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Two layers of 5/8 drywall with a viscoelastic sandwich mounted on a spring isolation system is the superior method, tell your contractor thanks but no thanks, if he comes back with an up-charge for Roxul, fire him he doesn't know what he is doing.
 

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Discussion Starter #13 (Edited)
Today I got an estimate from the builder our architect recommended. It's a little higher than expected, so I'm going to work with him some on clarifications to maybe bring it down some. The last thing we want to do is make the same mistake we made with the builder we chose to build the house originally. We worked with him so hard to bring the estimates down within budget that we ended up compromising on quality. I have confidence in this builder that the work will be top notch however quality ain't cheap. The good news is that they're able to start this month if we go ahead.

Also, we made another "pre-purchase". This is going to sound strange, but we bought carpet. Carpet tiles actually. We've purchased from FLOR several times in the past and absolutely love their stuff so when a rare 25% off sale came up we bought all of the flooring for the room. I know it's not as thick and sound absorptive as traditional carpet and padding but we just couldn't find a pattern we liked in regular carpet and we do like how FLOR is easy to clean or even replace a tile if necessary. The black will go along the screen wall 1.5 tiles deep and the pattern, "Hollin Hills", in the rest of the room. Any tips on controlling sound reflections with a more reflective floor are appreciated.

I helped the UPS guy deposit these in the garage.



 

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Thanks for the replies everyone.


@sassuki I hadn't considered using the bar as a sub enclosure. I'll have to marinate on that a bit. I feel like 12 cubic foot enclosures for Ultimax 18s wouldn't leave any leg room but maybe smaller drivers would work.

Here’s the example I was trying to reference for the bar subs @blazar did an awesome job:
https://www.avsforum.com/forum/155-diy-speakers-subs/2961530-perfect-bass-recipe-mso-mbm-harman-curve.html#/topics/2961530?page=1

It’s a beautiful room, you should really check it out if you haven’t seen it already.
 

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Discussion Starter #15
@sassuki thanks for the link to the bar subs. That's a great build I hadn't seen before. I'm going to continue with a plan to put the subs down in the riser because I think it's the best use of space and more closely balances the front subs.

That's what I'm thinking - space inside the framing of the riser to drop in 2 ~12cuft vented enclosures for the Ultimax 18" subs. Max height on the enclosures will have to be
 

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@sassuki thanks for the link to the bar subs. That's a great build I hadn't seen before. I'm going to continue with a plan to put the subs down in the riser because I think it's the best use of space and more closely balances the front subs.

That's what I'm thinking - space inside the framing of the riser to drop in 2 ~12cuft vented enclosures for the Ultimax 18" subs. Max height on the enclosures will have to be
 

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Discussion Starter #17
It would be nice to hide them away in the riser like that. I had originally thought I was going to do something similar, but didn't want to design some complicated riser structure to go around the boxes. (I got lazy). will the drivers be directly under the back row of seats? I look forward to seeing what you come up with.
Since these are intended to be balancing subs to even out room modes, the drivers will be close to the rear wall. The back row couch will be forward of the recesses.
 

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Discussion Starter #19
I made another pre-purchase for the theater. I took advantage of Parts Express' limited time sale on the Ultimax 18 inch subs. After the discount and using 2 of the $50 coupons on separate orders I saved $364 on a set of 4 drivers. That should cover materials for the cabinets.

I suspect they're clearing inventory for the new models that are rumored to come out this year.
 

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Discussion Starter #20
I've had some time to think about the ventilation while I waited on the bank. I'm considering using the equipment closet (~800 ft3) as a space to exchange air in the theater. That means terminating the ventilation supply and return ducts to the closet and adding separate supply and return ducts (and another fan) to exchange air in the closet with the rest of the house.

Dead-vent-type construction will be used on all of the ducts.

There are a couple of reasons for this. First, I'm concerned about heat buildup in the closet; this will add ventilation to the closet. Second, i think there might be opportunity to reduce sound transfer though the ductwork by terminating the ductwork from the theater to the adjacent room and not to the rest of the house.

I understand that there will be no cooling benefit to the room but that's why I will have a minisplit feeding the room.

Am I right in my line of thinking on this? It's a bit of extra work, will it be worth it?
 
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