New Home Construction - How big should the A/V room be? - Page 3 - Home Theater Forum and Systems - HomeTheaterShack.com

Old 07-30-07, 02:59 PM
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David

Join Date: Oct 2006
Location: Fontana, CA
Posts: 3,251
Re: New Home Construction - How big should the A/V room be?

Quote:
owlfan12000 wrote: View Post
...I appreciate all of the suggestions. I've been giving it a lot of thought and here's where I'm at for now. After looking at some theater seating sizes I've decided to add a ft to the width... HxWxL of 9x12x23. ... I'm trying to keep things in the house wheel chair accessible for when I get old and feeble. Any suggestions on how much I need to lower that area for a second row of seats to have a good view?...
I think that the room need to be wider (there is only aprox 18" between the seat and the wall) ... I think you need more than that, I have 11" in that space, and sometimes you have to be a contorsionist to get to the second row ..... I'm assuming that if you have somebody in a wheelchair you will acomodate them in the back row, Right??.

If you make the room wider, you will have more space to a install the speakers, without changing the screen size as the other suggestions ....

I have a riser, it is 14" high ... there is a formula to calculate the height (I don't remember where I got it, but it was on the internet and ask you for distance, height of seat, height of the person that will be seated, height of the screen from floor, etc.) .... I think if you lower the front 14" will be okay ... but maybe you need less than that ...
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Old 07-31-07, 12:37 AM Thread Starter
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John

Join Date: Jul 2007
Location: Tulsa, OK
Posts: 66
Re: New Home Construction - How big should the A/V room be?

Okay, some easy responses first. I think 12' is about all the width I'm going to go with. Since the house is single story it's already getting a little wide for the lot. Also every foot in width adds about \$2K to the home cost that I'd rather put into something else. I'm thinking about having an armless recliner in the middle to reduce the width or choosing a design with narrower seats or only doing that in the back row.

Yes any wheelchair seating will be in the back row but hopefully not for many years. My wife and I are both healthy and have no reason to believe we'll need to use a wheelchair we're just planning for that possibility in the design.

As for the screen size, I went to the viewing calculator and tried it out for 12' and 18' viewing distance with a 118" screen. The results are attached. Does that seem more reasonable? The 118" screen seems to fall into the THX seating recommendations. Does that allow enough room for appropriate speaker placement? (107" x 62" outside frame)

For reference, at the theater I usually go to there are three or four rows up front, an 8 to 10 ft aisle, a row of handicap seating and then the main risers start. I hate the front rows but usually like the first row after the the handicap seating.

More questions now -
Are there other tradeoffs for choosing a screen that size? Are there other screens I should consider? While I'll have no windows and complete lighting control I would like to be able to see this reasonably well if I have the lights up for a Super Bowl party. Will this screen/projector combo be OK? Do I need the bright white screen?

Just when I think I'm getting a handle on this I read more postings which generate more questions. That's OK though I'm enjoying the research. Pretty soon though I'm going to have to stop asking questions and contract with the builder. My wife is getting impatient.
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Old 07-31-07, 11:47 AM
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Joe

Join Date: Jun 2006
Location: Oregon Coast
Posts: 68
Re: New Home Construction - How big should the A/V room be?

I'm at the stage of construction where some of the decisions I made at the beginning of our home construction are starting to pay off, and your situation is pretty similar to mine (budget/seating/room size), so I thought I'd chime in:

Not to beat a dead horse, and ignore this if the decision's been made, but I'll throw in one more vote for the wider room. Our first plans showed a 12' x 22' room for the theater, and now that it's nearing completion, I'm very relieved that we increased it to 15 x 22. 12' looked pretty good on paper, but going even a couple feet wider will be well worth the money. Actually, it was my wife who suggested the larger room - She said a few thousand dollars on a fifteen-year loan at a good interest rate to get the room I want is well worth it, since it can't be easily widened later. The extra space not only helped seating access, but surround speaker placement, acoustic treatments, screen width, etc.

If you do keep the 12' width, you might want to incorporate acoustic treatments into the walls and cover those areas with cloth instead of sheetrock. Bryan or Ethan could answer this better, but I think room treatments added to the wall surface might take up space you can't afford to lose. I did the 1st reflection points and front wall that way just for aesthetics and it seems to work well, but I'll probably still add panels later.

My seating is at 12' and 18' and I went with a DIY 124" wide 2.35:1 fabric screen. I did try painting the wall (I've tested screen, lighting, speaker, and seating placement several times during construction), and it looked OK, but I wanted to do some lighting behind the screen so I went with fabric mounted off the wall about 4".

One other consideration for screen size is the projector location. I can't have much lighting on in the room because my projector is so far from the screen. My total theater area is 15' x 28', but I built a 15' x 6' equipment room at the back of the theater and my projector is in there shooting through a hole in the wall. With a 10' wide screen and 22' throw distance, I need to keep the room pretty dark for wide-aspect movies. It's not too bad at 16:9, though.

Joe

Last edited by AverageJoe; 07-31-07 at 11:50 AM. Reason: typo
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Old 07-31-07, 03:09 PM
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Bryan Pape

Join Date: Sep 2006
Location: Wildwood, MO (St. Loui
Posts: 5,220
Re: New Home Construction - How big should the A/V room be?

The only problem with incorporating them is that you lose the isolation layer. Realistically, one can properly do a room with only 1-2" panels on the side walls if we can deal with the lower frequencies in the front, back and corners.

Bryan

I am serious... and don't call me Shirley.

Bryan Pape
GIK Acoustics
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Old 08-01-07, 09:08 AM Thread Starter
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John

Join Date: Jul 2007
Location: Tulsa, OK
Posts: 66
Re: New Home Construction - How big should the A/V room be?

Joe - I doubt if I'm going to add any more square feet to the house. Adding 3 more feet to the wall would add \$7640 to the construction cost (\$10,620 over the life of that 15 year mortgage). I think I might be better off investing in some of Bryan's room conditioning. I may decide to steal a foot or so from the kitchen/great room area. I am curious about the lighting/projector issue - did you need to place it so far back because of some projector constraint or was it just the fact that you wanted the equipment room back there?

Bryan - I was looking at the Surround Sound diagram in the acoustic primer on your web site. When I try to place a circle around some hypothetical point in the room I end up with the front speakers nearly in the front row (see the new picture attached). I realize that the theoretical often conflicts with the room dimensions. Would I just end up placing them near the front middle and some distance from front corners and try to condition the space to accept whatever geometry that results in?

Can you also give your thoughts on the merits of having some drywall angles like I've shown in the back of the room? I noticed on Ethan's Real Traps site that there was a recording studio with a lot of hard surface angles (picture attached). As for some of your traps what would be a minimal requirement for conditioning a room like this?

I also wonder if something couldn't be done to make some of the traps more attractive. I got a couple of fairly large pictures handing in my living room right now. The frames are about 2" deep. If I had them reframed so there was a couple of inches behind the pictures and no glass could some acoustic material be put behind the canvas to provide decoration and acoustic treatment?
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Old 08-01-07, 10:19 AM
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Bryan Pape

Join Date: Sep 2006
Location: Wildwood, MO (St. Loui
Posts: 5,220
Re: New Home Construction - How big should the A/V room be?

The angled surfaces are a totally different thing in a studio. I'd avoid them if at all possible - it takes away easy places to deal with all dimensions acoustically. Also, do be of benefit, the amount of angle would cause you to lose a tremendous amount of space in the room which you frankly just don't have.

As for the circle, you have to extend out the angled lines to your situation - don't worry about the radius per se.

Bryan

I am serious... and don't call me Shirley.

Bryan Pape
GIK Acoustics
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Old 08-01-07, 01:38 PM
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Joe

Join Date: Jun 2006
Location: Oregon Coast
Posts: 68
Re: New Home Construction - How big should the A/V room be?

Quote:
owlfan12000 wrote: View Post
I am curious about the lighting/projector issue - did you need to place it so far back because of some projector constraint or was it just the fact that you wanted the equipment room back there?
It was mostly for looks. I preferred not to have the projector hanging from the ceiling so I tested how far back I could go without giving up too much picture quality, and selected that distance for the equipment room wall (I did hedge my bets a little and ran a conduit to a ceiling location just in case). All the source electronics and the DVD shelves will be in the back room - again, just for looks.

By the way, good decision in choosing acoustic treatments over room size if that was the trade-off. It was a good catch by Bryan regarding the isolation problems with in-wall treatments. I forgot all about that. In my case, I built the walls out to cover the short concrete stem walls, so I had a lot of room to play with above them. I'll still do other rteatments and bass traps, though.
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Old 08-06-07, 11:09 PM Thread Starter
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John

Join Date: Jul 2007
Location: Tulsa, OK
Posts: 66
Re: New Home Construction - How big should the A/V room be?

I've seen a couple of references to acoustically transparent screens. Are those significantly cheaper or more expensive than other screens? I've seen theaters built with space behind the screen before but I never realized this was for the speakers. Are there audio advantages or disadvantages to this setup?

I've been trying to figure out where to run wires in the room. I think I can figure out where the speakers would go. I assume that, given my narrow room the back center would be the best location for the equipment rack (saving the corners for potential bass traps). I'm not sure how to accurately place the projector without putting it up and seeing how it looks. I know it will depend on the projector itself, my desired screen size and the screen brightness. I recently read a review on the Optoma HD80 that was pretty impressive. Does anyone have any experience with this projection calculator from Projection Central? http://www.projectorcentral.com/Opto...ulator-pro.htm

I like it because it lets me see how the different components affect each other. It says that the results are based on numbers provided by projector manufacturer so I have no idea if it is accurate.

I'm also wondering if there is some way to sound insulate the projector without causing overheating problems because some of the placements that I come up with are right over the viewing area.

What are the acoustical costs of ceiling mounting some of the speakers? My sister has a new baby on the way so ceiling mounting would have an additional childproofing benefit.

Last edited by owlfan12000; 08-06-07 at 11:40 PM.
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Old 08-07-07, 12:38 AM
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John Simpson

Join Date: May 2007
Location: Hobart, Tasmania
Posts: 246
Re: New Home Construction - How big should the A/V room be?

Whew, that's a lot of questions, Owl

Regarding the AT screens, certainly they're more expensive. From my research, most are plasticised fabric perforated with little holes: this reduces the gain a little on the screen, but allows most sound to travel through (apparently there is a slight treble attenuation -- not a bad thing probably, as most movie soundtracks are a bit bright).

One brand -- Screen Research -- says they have a special woven screen that hardly loses any brightness, but can still allow the sound to pass through. They also cost a huge amount compared to regular screens. Incidentally, one of their fixed screen range is *curved* to suit the projector's throw... very snazzy indeed.

Regarding projector placement, I intend on building an alcove in a drop-ceiling bulkhead, which should isolate the project from the audience a little without reducing airflow. You should certainly NOT put insulating materials directly around the projector, or you'll be buying new bulbs each month as they burn out (or a new house after it catches fire!). The reason projectors are noisy is the fan keeping them cool.

Finally, ceiling monted speakers are getting better all the time, but a lot of HT purists think they place the soundstage a little too high. Nevertheless, it's again a case of "you get what you pay for"... better quality ceiling speakers will usually perform better than cheaper wall-mounted speakers.
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Old 08-07-07, 12:50 AM
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Shawn

Join Date: Jul 2007
Location: Topeka
Posts: 144
Re: New Home Construction - How big should the A/V room be?

John,

I would avoid the in celing approach. Remember, the higher frequencies above 500 Hz are more linear than lower frequencies which are spherical. So, your speakers, being aimed down, would fire the higher frequecies right at the ground. This would limit the spacious surround envelopment. Plus, you would not get the reflections off the surrounding walls which add to the spacious environment. You want to be able to have some flexibility with your LCR to help alleviate SBIR (speaker boundary interference reflections). I would reduce the size of the screen to say around 100" maximum. At the distance you have your front seats placed at, 100" should be more than enough to project an optimum field of view. If you can't widen your room, I highly suggest you eliminate two seats. With the distance from the side walls you have specified, you are likely to end up with a "exit door" effect at those outlying seats. Basically, the center front is your money seat and the only seat that is relatively optimum in your room with your current design. In addition, subwoofer placement will be limited since much of the side aspect of your theater is taken up by seating. Also keep in mind that placing seats side by side is not usally the best way to go either since you have room modes along the width of your room as well. Remember, I am only a few short hours way!
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