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: My layout is finished. I'm very pleased with it as it was a sanity check for everything I "think I know". Interestingly, my models were within an inch or so of the layout Dennis provided. The big differences were screen size and obviously Dennis included the acoustic treatment plan.
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: For now I'm planning for a 138" wide by 64" high screen. 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.
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.
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.
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.
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
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.
1) I've read on the boards that the RT60 needs to be between 0.35 and 0.4.
1) Below is the often referenced seating distance chart.
Other Threads About The Plains Theater
- 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.
- 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.
- 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.
- Wides are recommended before heights when considering a 9.x setup.
- Wides should be set at ear height.
- 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.
- Clips + Channel at Outside Corner
- Beam 2" Below Ceiling - Need Suggestions
- Door Location and Size Advice Thread
- Soffit Heigh Advice Needed
- Where Do I Locate My Conduit and Power Feed for My PJ?
- Questions About Drywall And Green Glue on Back of Subfloor - Also includes link to 1-1/8" screws that are needed.
- Custom Door Jamb Question - Use 3/4" Ply or a ripped 2x8 for trimmer when a wide jamb is used.
- Fire blocking decoupled walls - There is also some good information on fireblocking here as well.
- Attaching trim to decoupled walls - Short thread, essentially just use liquid nails and finish nails or brads into the DD
- Light Spacing - Thread discussing light spacing the theater. Some good info here for determining the layout.