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Building a home theater questions

Discussion in 'Home Theater Projects' started by JEDI144, Mar 17, 2019.

  1. JEDI144

    JEDI144 Auditioning

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    Hi,

    I am building a new home with a room specifically for a theater construction will start in the next month or two. In my current home I have a theater and will be reusing the subs, LCR and buying surrounds and heights.

    The room will be unique as it will have ICF walls on all 4 sides and an ICF ceiling. ICF is a sandwich of 2.5” of insulation on both sides with a 4” core of solid concrete (drawing attached). Two benefits; sound will not escape and the room will be like a bunker during a hurricane. The door will be sound deadening with a sweep. The room will have a window behind the rear row. The room is 13’ 8” W x 20’ 9” D x 8’ 4” H (I lost 10” ceiling height due to concrete ceiling).

    My plan is to wire for a 7.2.4 (ATMOS) and utilize it as a modified 5.2.4. I am going to have two rows of 3 movie style theater seats with a riser (7”) for row two. The picture shows couches that are dimensionally accurate for theater seats. After much research and previous experience I have decided to split (Y-cable) the side surround signal so each row has their own sweet spot. The speakers will be wall mounted, monopole and set at ear level (which will vary between the two rows). Due to the concrete ceiling I will be using height speakers as well. So here are some questions:

    What are the thoughts on:

    How to position the side surround speakers?

    · Slightly behind each row and angled toward that rows middle seat?

    · In line with the seats in each row.

    As stated earlier I would like 6 seats. I currently have 5 seats in mu current house on a 6” riser with a 92” screen with the bottom of the screen 35” from the floor. Due to the offset of the seats no one’s view is blocked.

    I am considering a screen size of 110” that is 16x9. In looking at 4K projectors it appears Optoma and Epson they are, large in their thickness and they need to hang down fairly significantly where they may be in the way. In looking at Benq they do not have this issue. Unless of course I am misinterpreting the throw calculators on the respective websites. This has me a bit perplexed.

    All wires will be in the wall. The equipment will be in the next room and controlled via a remote repeater. With some slack left over the HDMI cable will be about 40 ft. So a 50 footer is probably on order. If the builder does it right I will be able to pull replacement wires. I will also be using 12awg wire that is CL3.

    Thanks in advance for your thoughts and input.
     

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  2. Bobofbone

    Bobofbone Second Unit

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    Interesting concept. I had some of the same thoughts when I designed and had my house built. My wife vetoed the idea of concrete walls and ceiling around the theater for sound reduction and tornado protection, claiming the area we lived in hadn't had tornadoes. Just before the house was completed, we had some. It was quite interesting to see them tear a path through the woods, hit the river and dissipate their energy sucking up water as they came towards us. But, they were small ones.

    I'm not sure where you will be living, and if, from your post, hurricanes are more of a consideration than tornadoes. There are some publications concerning safe rooms, with hurricanes and tornadoes in mind. One is : https://www.fema.gov/media-library-data/1467990808182-0272256cba8a35a4e8c35eeff53dd547/fema_p361_July2016_508.pdf but it doesn't get into specifics in construction, and refers to more publications. Section B addresses construction. It mentions, somewhere, to expect a wind loading of 100 pounds/sq ft, under tornado conditions. The dimensions of your room include some fairly large walls. You also mentioned a window on one wall. With a direct hit from a tornado, there is also a pressurization and depressurization that the area has to withstand. If the structure is not strong enough, it may collapse during the cycle. It also has to protect from flying debris, and a window may need to be shatter resistant. Some polycarbonates used for windows may also become brittle after prolonged UV light exposure, decreasing protection particularly if the window is external. If there is much of a structure above the area, the room also has to withstand whatever falls on top of it after the weather hits. If you are using insulated concrete form construction, I'd include steel reinforcement in the area, at a minimum.

    The effects of a tornado can vary. I was next to one going by (yes, the rain does actually become horizontal just before it hits, and they do sound like a high speed freight train going by) that took out the building next to to me, and left the plate glass windows intact in the building next to it. But, it you intend to have the room you're using function as a safe room, you should plan for the worst case. I'm not an engineer or architect, and these are my thoughts my looking into the idea some time ago. Were I to pursue the idea again, I'd get the input of an engineer or architect with expertise in the area before I finalized my design.

    The theater portion of your plan looks good.
     
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  3. JEDI144

    JEDI144 Auditioning

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    Thanks for the reply. I am building in Florida and all exterior walls will be ICF as well. The windows are made with hurricane glass. The roof will be hips style with a 5/12 pitch built to current Florida code which is quite strict. Hips roofs have less exposure to wind due to the design. One thing not mentioned is the the energy efficiency of ICF. Even if the roof were to blow off the theater room should be dry and safe. Hopefully it does not come to that. The plans include engineering for the walls and ceiling (insuldeck). Both walls and ceiling include steel reinforcement. Thanks for the thoughts.
     
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  4. Josh Steinberg

    Josh Steinberg Executive Producer
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    Welcome Brian!

    I can't speak to much about your project as a lot of this goes over my head, but I can speak to Epson projectors more generally. They tend to have a huge amount of flexibility for placement due to generous lens shift capabilities. So you probably would have a bit more freedom with where an Epson has to be positioned relative to other brands.
     
  5. JEDI144

    JEDI144 Auditioning

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    Thanks. I am more interested in thoughts on the surround placements. I.E. behind or to side of each row as I will have two sets of surrounds also projector placement.
     
  6. DigitalDawn

    DigitalDawn Agent

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    Where in Florida are you building?
     
  7. JEDI144

    JEDI144 Auditioning

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    Punta Gorda
     
  8. DaveF

    DaveF Moderator
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    In building a 7.2.4 theater, I went with one row with ideal sound and the rear row with compromised sound. My space didn’t allow for side speakers to be set for the rear row.

    That’s to say: I looked a little into the issue of multi-row speaker setup. What I found concluded is there’s no right answer. It’s not something consumer home theater specs/hardware/media address.

    Given your goals, can you wire 9.2.4 for a multi-row 7.2.4 setup? This seems to eliminate the concern over speakers in line vs behind the row. For 7.x.x the speakers are in row with seats.

    But if you’re doing 5.x.x it looks like the speakers should be slightly rear of the rows.

    https://www.dolby.com/us/en/guide/dolby-atmos-speaker-setup/5-1-4-setups.html
     
  9. DigitalDawn

    DigitalDawn Agent

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  10. JohnRice

    JohnRice Executive Producer

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    I was thinking the same thing. Either that or surround speakers with very wide dispersion. These Emotivas would be another option. The ELAC Debut v2 models could also be a good solution, due to their very wide dispersion.
     
  11. JEDI144

    JEDI144 Auditioning

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    Thanks! Do you have an ATMOS set-up. I had Dipoles (not Bi-poles) in my current theater which I replaced with monopoles and feel the imaging is better. I would have to go audition some bi-poles I do not think the wall cavity will be deep enough for in-wall.
     
  12. JEDI144

    JEDI144 Auditioning

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    The ELAC Debut V2 are 6 ohms. My amps are 8 ohms would that be an issue?
     
  13. JohnRice

    JohnRice Executive Producer

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    What would you be driving them with? 6 Ohm is usually pretty safe, plus surround speakers put less of a demand on the amplifiers, but it is something to look into.
     
  14. JEDI144

    JEDI144 Auditioning

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    I have 5 Fosgate Audionics 4 channel amps (model 4100 and 4125). They are from the 90's but are great amps.
     
  15. TonyD

    TonyD Who do we think I am?
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    Hi.

    I don’t t have anything to add besides good luck, welcome to HTF and welcome to Florida unless you already lived here.

    I’m right down the road in Cape Coral
     
  16. JEDI144

    JEDI144 Auditioning

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    Thanks
    We will be retiring in a few years from Illinois.
     
  17. JohnRice

    JohnRice Executive Producer

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    They would be fine, as long as you don't bridge the channels. Since you have a total of 20 channels of amplification, I expect you are bridging them, which probably wouldn't be a good idea with any speaker of less then 8 Ohm impedance. Bridging two channels into a 6 Ohm speaker results in an actual impedance of 3 Ohm.
     

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