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The Plains Theater

251K views 3K replies 122 participants last post by  J_P_A 
#1 · (Edited)
After reading as much as I could on this forum over the past several years, I’m finally ready to post my own build thread (my 500th post seemed as good a time as any). On one hand this seems like a huge step forward because I’ve waited so long to start, but on the other it’s still going to be a long time before I even get to put up the first 2x4. So, fair warning, this is going to be very slow, particularly to begin with as we have to build the house before I can actually start on the theater. Fortunately, to some degree we’re designing the house around a space for the HT, and this is what we’ve got in mind:

1) I intend to use the pro layout service, but I want to get the orientation of the room with respect to the rest of basement hammered out before I have the room designed by the pros. I will need the scale drawings from the architect to make sure I give Dennis and company the correct dimensions of the space.
EDIT: I ended up using two Pro Design Services. I first contracted Dennis to do a layout and acoustic plan. Dennis heavily favors the Quest treatments, but they weren't in my budget, and I didn't feel the DIY treatment plan he provided was detailed enough (essentially just replace all the panels with fiberglass panels). From the room layout standpoint, Dennis' layout was a good sanity check for everything I "think I know". Interestingly, my proposed layout, what I worked out based on what I read here, was within an inch or so of the layout Dennis provided. The big differences were screen size (Dennis didn't like my 160" screen :) ).

Once the room was drywalled and I was getting ready to finalize speaker locations, I decided I wanted a DIY'able acoustic plan that would take better advantage of the extra space I had available for treatments. I contacted Nyal at Acoustic Frontiers. You can see the resulting plans in post two below. Working with Nyal was a great experience, and I highly recommend contacting him as soon as you decide you're ready to commit to a space! There were lots of small tweaks to my layout that he recommended and I feel like the acoustic plan is a good compromise between engineered products and DIY. The money I saved using Nyal's treatment plan as opposed to Quest products more than paid for Nyal's analysis of my room


2) The theater will be in the basement with no exterior windows.
3) We want to have at least an 18’ x 24’ x 9’ space, but I would like to go as much as 19’ x full width of the basement if I can (around 32’ not counting odd nooks).
EDIT: The room ended up being 18'-10" x 30'-3" x 9'. There is an odd section at the back that adds another 2' for a total length of 32'-9" for half of the room, and a beam that will lower the ceiling by 2".
4) Right now I’m planning to use DD+GG, but I haven’t decided on which method to use for decoupling the walls yet (Room-within-a-room if possible, clips and channel if not).
EDIT: After talking with Ted, I've decided on clips and channel for ceiling and walls with a joist mufflers to isolate the HVAC supply and crossover duct to the adjacent room.
5) We are planning to have two rows of seating with a bar at the back for overflow seating. We intend to use this primarily for movies and gaming, but we also enjoy football and would like to host football parties during the season.
6) I would like a 2.35:1 AT screen, and after reading Tony123’s thread, I’m thinking 14’ wide sounds pretty good.
EDIT: I went with a 160" wide by 67.5" high screen (2.37:1). This should optimize 2.35 as well as 16:9 content for my room. I'll have bars for both, but they don't really bother me, and I can always add a DIY masking system later

EDIT: I don't like trying to pick the equipment before my room is done because the current tech changes so quickly. However, I've learned that I need to at least have an idea of what I'm going to use in order to locate things in the room. With that in mind here's a couple things I'm considering: 
7) I'm considering either a Panny AE7000 or Epson 6010 for a PJ. a 12' or 14' screen is really going to be pushing either of these, but PJ technology improves every year. I'd rather build my room for a larger screen and update my PJ than have to redesign my room once the PJ will support a larger screen. I like the Panny as it would allow a memory zoom for 2.35 content, but I believe the EPSON is a little brighter.
EDIT: I went with a Sony VPL-HW40ES and a Panamorph UH480 A-lens. I got an amazing deal on both, and I'm very happy with the results. Even with the huge screen the image is plenty bright for my tastes, and I have zero regrets about going with such a large screen. This is an area where all the pros will tell you not to do it, but if you have to go with what you like!
8) Speakers are going to be a bit of a challenge as they will need to be high efficiency. I'm thinking something DIY like 4 Pi's or possibly the new SEOS project might be a good way to go.
EDIT: I went with three DIY Soundgroup Fusion 15s up front and Volt 8s for surrounds (two rows of side surrounds plus back surrounds). I'm also installing RSL C34E overhead speakers for atmos.
9) With a room this size, 7.x is a no-brainer. It may require multiple side surrounds due to the multiple rows. I'm not sold on the 9.x or 11.x just yet, but it shouldn't be too hard to retrofit in a room with soffits and columns.
10) For subs, I'm thinking 3 or 4 to help with room modes. I'd love to get some of the Danley DTS-10's, but I'm not willing to pay for the assembled units. If they do another kit, I may pick up a few. Otherwise, something like 4 F-20's might be a good option.
EDIT: I went with two lilWreckers up front. LOTs of output! More subs for room modes would be helpful, and I'm still lacking some mid bass punch.
Here's a top down view of the basement and theater. Again, the theater is 18'-10" x 30-3" x 9'



Index: I thought I would start an index of posts that I've found helpful while researching my theater. For now, it's just HVAC related, but I hope to update it as I run across useful stuff. Also, a good deal of this is lifted directly from the Dark Knight Theater, so you should really check out that thread if you're interested in a more comprehensive list of information.

HVAC
1) Your HVAC contractor is concerned with volume. They will calculate room requirements as Cubic Feet per Minute (CFM). They will size the ducts according.

From a noise perspective, we are concerned with Feet Per Minute (FPM) or velocity. To keep your diffusors (registers) from creating a lot of air flow noise, you do not want more than 250 FPM through a slotted or bar type diffusor. Therefore, let the HVAC contractor size the system but you insist upon the velocity...which will mean larger ducts and larger diffusors.

From a capacity perspective, the HVAC contractor needs to look at the demand of the room to be on the same order as a kitchen (that's if you cannot calculate latent and sensible BTU requirements). For example, six people sitting in the room will require 3000 BTU's/hr. (exclusive of equipment, etc). - Dennis Erskine


And another similar recommending that you size your HVAC based on a kitchen - by Dennis Erskine


2) Returns are high mounted (ceiling) and to the rear of the room. Noise transmission in the returns should never exceed the noise from the supplies and the system must be designed this way. Supplies are in the front of the room, high mounted (ceiling) and not near the screen. Diffusors should be Lenticular, slotted or bar type (www.nailor.com) and located in such a manner as to avoid drafts directly into seating locations. We typically will use the soffit as a duct chase to avoid direct penetration of the drywall barrier.


CFM counts when determing the cooling requirements of the air handler; however, for noise criteria, FPM is critical and should not exceed 250 FPM. The noise created by various diffusors may require a lessor velocity. - Dennis Erskine


Here's another post pertaining to the maximum desired velocity of 250 feet per minute.
3) Equally useful, is to increase the size of the duct by one size, have your HVAC contractor balance the system so that the VELOCITY of the air at the registers is 250 feet per minute or less. (Don't let them get confused between VELOCITY (fpm) and volume (CFM)). In other words, you want them to deliver the required CFM but at an FPM of 250 or less. - Dennis Erskine
4) Nah...don't think so. You'll want two supplies (typically in the front of the room, high mounted) and two returns (high mounted) in the back of the room. You do not want air flow directly on any seating location. You do not want a velocity of more than 250 FPM through any vent (diffusor). You want the HVAC system to maintain a temperature of 70 degrees F with an outdoor temperature range of -30 to 100 degrees F and to maintain a relative humidity of not less than 25% nor greater than 50%. You want six air exhanges per hour and 15 CFM of fresh air per person. - Dennis Erskine

HVAC SIZING
1) This theater has a single 8" flex supply line and no returns. From the table below, this should provide approximately 160 cfm of cooled air. It will be slightly less as the total length is greater than 25'



2) 1 Ton of cooling is equivalent to 12,000 BTU/Hr
3) 1 Ton of cooling can supply approximately 400 cfm of cooled air. This is a general rule of thumb used for sizing HVAC and will vary.
4) Each person generates roughly 500 BTU/hr at rest
5) Not considering the bar area, the theater will seat 8 people. This will require 4000 BTU/hr of cooling (8people * 500BTU/hr/person). I am assuming that when the theater is full including the bar at the rear (10 or 11 people), we will likely be watching a sporting event like the super bowl and will have the door open anyway.
6) The required cfm of cooled air is approximately

400 cfm/(12000 BTU/hr) * 4000 BTU/hr = 134 cfm


7) This is less than the 160 cfm supplied by the 8" duct.
8) The rule of thumb is at least 6 air exchanges per hour. The room is roughly 19x31x9 = 5301 c.f. (closer to 5,000 c.f. once the riser and stage volumes are accounted for). So 5301 c.f * 6 exch/hr * 1 hr/60 min = 530 cfm
9) The 8" supply will provide approximately 160 cfm, this leaves 370 cfm that must be provided by dead vents.
10) Here is a link to the Panasonic FV-40NLF1 fan that moves ~ 400 cfm.

Acoustic Treatments
1) I've read on the boards that the RT60 needs to be between 0.35 and 0.4.

Seating Information

1) Below is the often referenced seating distance chart.


Speaker Locations
  1. Below is one of the many speaker layout guides. This is the Audyssey layout for 7.x/9.x/11.x. The Dolby recommendations for PLIIz are pretty similar for heights, so this seems reasonable for layout purposes.
  2. Audyssey recommends +- 10 degrees for their azimuth positioning shown in the above guide. My front columns look like they will be at about 67 degrees from the center seating position. so this will be perfect for the front row, but I'm ~40 degrees from the back row. I suppose you can't make them all a money seat.
  3. Audyssey also recommends putting the front heights slightly wider than the L/R and as high on the wall as possible. Obviously, 45 degrees will not be possible in my room.
  4. Wides are recommended before heights when considering a 9.x setup.
  5. Wides should be set at ear height.

Other Threads About The Plains Theater
  1. Return Duct In Riser- I've decided against this due to the length of the duct run. I'm planning for a short just muffler/dead vent for the return.
  2. Clips + Channel at Outside Corner
  3. Beam 2" Below Ceiling - Need Suggestions
  4. Door Location and Size Advice Thread
  5. Soffit Heigh Advice Needed
  6. Where Do I Locate My Conduit and Power Feed for My PJ?
  7. Questions About Drywall And Green Glue on Back of Subfloor - Also includes link to 1-1/8" screws that are needed.
  8. Custom Door Jamb Question - Use 3/4" Ply or a ripped 2x8 for trimmer when a wide jamb is used.
  9. Fire blocking decoupled walls - There is also some good information on fireblocking here as well.
  10. Attaching trim to decoupled walls - Short thread, essentially just use liquid nails and finish nails or brads into the DD
  11. Light Spacing - Thread discussing light spacing the theater. Some good info here for determining the layout.
 
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#1,781 ·
This seems like a good time to post up some more progress shots as the track saw came in pretty handy as you will see.

before I put the decking down on the stage I proceeded to rip my MDF into 28" sheets for wainscoting, 15-1/4" widths for the column sides, 17-1/2" widths for the column fronts, and I took some of the scraps and cut them down to 16" wide for use in the column backs. I did this in the middle of laying decking because my dad was there to help move the MDF. I ended up having to handle the last few sheets myself, and it made me even more grateful that I had my dad to help part of the time. Again, track saw was a huge help here. I can't imagine trying to wrestle a full sheet of 3/4" MDF onto my table saw, especially without help.

Back to my teaser shot from before, this is where I started laying out the columns for assembly. The short pieces are for the back. This serves to keep the column square and gives me a point to mount to the wall. I decided at 16" deep, I could afford to lose 3/4" for a good mounting point. The two long pieces are the sides.



Here it is during assembly with the sides attached to the back. I even put in some blocking to help strengthen things up. Not sure it was necessary, but it only took a second.



Here I've put the front on the column, so I essentially have a long box.


Next I needed to cut the openings for the speakers. I'm using the Savoy as a guide for all this, BTW. I decided I wanted the opening as large as possible, so I laid out where I wanted the trim to go framing each opening. I moved in 1/4", and used that for my opening. I'm planning to build fabric frames to go in the opening, and attach my trim to the front with 1/4" overhang that will hide the cut opening in the column.

With my openings laid out on the column front, here comes the track saw again. Because it's a plunge cut saw, I could use it to cut out each opening.


I used the short track to make the horizontal cuts.


And here's what I was left with.


The plan was to come back and clean up the corners with the jigsaw, but I needed to keep the panels from falling and tearing out the corners on the last one. I wish I could say I planned this, but it I just so happened to have the perfect thing to catch each panel :D


And this is what we ended up with.



With the next update we're going to talk about column placement, though you can see a hint of what's to come in the background.
 
#1,784 · (Edited)
second.

Here I've put the front on the column, so I essentially have a long box.
It looks like you built these and then 'tipped up' into place? The front column looks pretty 'tight' to the ceiling, did you only need to make 1/2" short?

.... oops, I guess since this is going under the soffit, you can simply tilt it up on the main ceiling height and slide it in... figured this out when I looked at my post!!
 
#1,785 ·
I cut them about an inch short so that I could slide them easily, but you're on the right track. I tipped them up, and then pushed them back under the soffit. The extra space also let me shim the bottom of the columns to get them plumb front to back and side-to-side as well, which helps out with the wainscoting panels. Fortunately, there was very little shimming necessary, though I did add about an 1/8" to the two front columns just to get the MDF up off the floor. Probably not necessary with the roofing felt, but I figured it only took an extra minute or two. The gap at the top will be covered by trim, but I'm getting ahead of myself.
 
#1,790 ·
…...So question now is you on vacation for a while or is this going to continue? That saw does look pretty awesome ! I really should get one of those.
I don't know is the answer. I've got a ton of stuff on my plate right now, so I don't know when I'll get time to work on the theater again. If it was up to me, I'd take two weeks and finish construction. I could probably do it in a week, honestly. I just don't get much time in contiguous blocks. Even after construction is finished I'll still need to build speakers and deal with acoustic treatments, but that stuff is easier to handle in little blocks when I get time.

We'll just have to see. I do still leave a few pictures to get us up to date on progress, though. Like I said, it was a busy week :D
 
#1,795 ·
What do you guys think about the flat packs for the DIYSoundgroup speakers? For the surrounds we're talking 26 ea. I'm sure I could save $100-$150 building them myself, but I'm not sure it's worth the trouble. I realize it's only been a handful of posts since I posted that I was on a tight budget, but the flat packs are going to be higher quality than what I'd be building myself.

On a side note, here's the sheet of foam insulation I've been using to make all my cuts. I've read where people will use a sheet of this for years, but I don't know that mine will make it through this project :) Either way, it's a wise $15 investment!



And here's my homage to BIG. Why they only had pink respirators, I'll never know. Hmmm… I need a haircut!



Despite the sweat on my forehead, I've been pleased with the way the room stays cool. WIth my dad and I in the room working pretty hard, it got warm once. I went and looked at the thermostat and the basement was at 75 degrees, and the air was not running. I turned it down to 74, and within minutes the room was much cooler. I also expect much better mixing once I get some registers on the vents.
 
#1,796 ·
What do you guys think about the flat packs for the DIYSoundgroup speakers? For the surrounds we're talking 26 ea.
I'd absolutely go this route, without question. I can't imagine creating the little jigs and templates you'd need to make for your router, not to mention all the chiseling and sanding needed to make everything fit. Your time is worth more than $100 - $150 and I'd think you'd be happier with the final product (nothing implied about your woodworking skills, of course!).

I like that foam idea if I needed to cut on the floor.
 
#1,798 ·
The flat packs are a great investment if the shape fits your requirements. Somehow, about half of my cabinets need to be non-standard and there were no flat packs for Cheap Thrills - so I have built three cabinets with 3/4" MDF from scratch (Cheap Thrills), two cabinets with 3/4" plywood from scratch (subs), and two cabinets from plat packs (more subs - from parts express, but they're effectively, if not actually, identical to Erich's). I still have 4 (or 6) more cabinets to build for surrounds - and they will be from scratch as well. I would not be shy about building from flat packs, where possible.
 
#1,802 ·
I don't disagree that it's easy to build a box, but the material is certainly a consideration. The flatpack for the surrounds are 1/2" Baltic birch. Much nicer than MDF. I don't know about the rigidity, though. The flat packs are also rabbeted so the pieces are easier to put together with just glue and clamps since there is an edge for pieces to be clamped against.
 
#1,803 ·
Yeah if you want to go the clamp and glue route the dado cuts and stuff are nice on the flat packs. I sometimes do those myself too, but then you are getting into more work. MDF > Baltic birch for sound quality due to density of material. Baltic birch is nicer to work with perhaps (cause MDF just sucks) but again I would rather make my LCR speakers from 3/4" MDF than Baltic birch. The higher density and heavier weight is actually a good thing, the stuff that makes MDF suck to work with is the same reasons why it's great for speakers. With 3/4" and a brad nailer you'll have your boxes together in like 2 hours. The BB is because some people want to stain it.

Seriously, I chopped up all this yesterday after work AND sprayed it. [this is only about 25% of the 10 sheets in the pics]

It's your choice on the flat packs, but if you are doing 7 speakers, it's going to add up. It's just square pieces of wood. If you like BB better than MDF just buy a sheet of that instead. I think it would be a difference of $100 for flat packs or not if you are doing a full 7 speaker set up. It simply comes down to what is more important, that money or your time ? I can tell you with certainty that using tightbond or construction adhesive and then brad nailing 3/4" MDF is more than solid and you don't need dado cuts and all that. I think the brad nailer is easier. Just line up and shoot. Line up other side shoot. Shoot one or two in the middle and place it off to the side so the glue can dry. It's like 15 minute thing. You won't even spend 3 hours I bet doing them all like that, including cutting the wood.
 

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#1,807 ·
Lol. I ran out of horses but seemed to have an over abundance of beer cases laying around.

I actually fired up the margarita machine, but it was so hot out it woudn't freeze in time.



So I made due with beer:



I need something to drink when I work. And speakers and good tunes. BEER + GOOD MUSIC = Productivity !



I am debating if I should go right now and spray the finish coat on those closet shelfs or not. I am thinking no. I'm feeling lazy.
 

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#1,805 ·
What is the cost of the FUSION 15 flatpack BTW? Shipping seems like it would be an asskicker on something that large... For the bookshelf it's tempting but once you are going to cut one you might as well just cut them all IMO. The larger 15" offerings will be more expensive because they use a lot more wood, and also weight a lot more.
 
#1,806 ·
I don't know. I suspect he'll post the flatpack the same time he posts the updated Fusion 15. I can definitely see where the cost of that would make it more attractive just to build the box since those will be MDF as well. Though apparently Erich uses higher quality MDF than we can get down at the big box store.
 
#1,809 ·
It's nice, it's that superlite stuff. It's actually more like light-medium density fiberboard or LDF. The best MDF from a performance perspective is the heavy ass stuff. Heavy is good for speakers. It sucks to cut and work with, and it makes terrible dust that will give you a sore throat but density and weight are your friend. For a speaker that will literally sit in place for years you want to make it dense as you can and heavy as you can IMO. Brace it well too. Do something like this between the top end and bottom end drivers:
 

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#1,812 ·
Lol! If it mattered I would have used the plunge cutter :p

Cross braces actually works almost as good btw... and it's really easy. I just use the miter saw and creep up on the ideal length. Once they glue it's good. You don't need crazy braces for bookshelfs but with 15" drivers and larger cabs you should take some effort there I think. Every 10"-12" should be braced. Once like I showed above between the top and bottom ends, and one cross brace behind the woofer should do it. Any vibration or resonance of the cabinet is lost energy, you don't want that. Treat the inside of the box with either recycled denim or that thinner stuffing stuff.
 
#1,820 ·
I suppose it's time for another update.

I'd decided that I wanted to move my side surrounds to a position slightly in font of the LP. So I built two columns to go on my riser steps. Fortunately, I decided to test fit them before I started mounting columns. It turns out that my lights are perilously close to the trim on the columns (photo further down). That's fine, except that these columns would be off-center of the lights. It looked like hammered duck crap, and moving the lights would require rebuilding sections of my soffit. As much as I wanted to move those columns forward, I decided to leave them where my DE design planned for them to go. So, I just cut the bottom off those two columns. Unfortunately, this left me with another problem.

If you remember, I ran all of my wiring in my riser with the plan that it would go from the soffit to the riser in a column. Well, now I needed to get these wires inside the box I'd built for columns…. That's easy enough to make happen :D


And here's the columns on one side of the room.



Here is a picture of how close the lights are to the columns. I did shift the back columns further apart per Nyal's recommendations. I centered them under the lights, so it looked intentional. Imagine that light just off the corner of the crown, and that's what the columns on the steps looked like.





This was the limiting factor on where the columns could go


One more update to come before we're at the current state of things!
 
#1,824 ·
I think we're on the same page. Just to clarify, I line up the base ply and the foam board. I lay the piece I plan to cut on top of that so that there is no overhang. That way, when I make my cut, nothing falls anywhere. Both sides are still laying on the foam (which is supported underneath by the base ply).
 
#1,830 ·
Be careful with ordering speakons - some of them are labeled PCB and have these tiny connections on the back that are meant to be soldered to a circuit board, I suppose. Don't get those. Make sure you get the kind with the barrel and set screw for each conductor.

It was recommended to me to get the 4-pole, for my subs, but I think it just makes things more confusing unless you plan to use all four. Of course for surrounds you'd have to be bi-amping to need four conductors, so I would get 2-pole for your application.

That said, I will get 5-way binding posts from Erich for my surrounds; they're much more compact.
 
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