Need advice on receptacle placement for basement please

[slisgrinder]

Please imagine a room thats 12' x 24' x 7'-8" (width x length x height). I want to get the biggest screen possible on the 12' x 7'-8" wall and after using the BenQ calculator for the W1000, the screen came to be 144" x 81". Now I don't have room for plugs on that wall anymore. What can I do? Could I install plugs on the wall and have a sound transmissive screen drop 2' from the wall (which wold be expensive) or have no plugs on the wall and use the wall with the right paint as the screen? Any other ideas would be nice.

I plan on building my own speakers in the future so this is just to future proof the basement to accommodate powered speakers.

Thanks for your time guys.

 

[AVRat]

So, you want to place powered, in-room speakers behind an acoustically transparent, fairly large screen, is that correct? For acoustic purposes, the listening position should be about 15' from the front wall and is what you should base your screen size on. For a 13' viewing distance, a 115" x 65" screen could be hung at the ceiling and may leave enough room to wiggle under.

 

[jostenmeat]

If you have the money (yes, it's expensive) go with a tab tensioned acoustically transparent screen.

My question to you is what is forcing a drop-down screen? How about a false wall instead? Is it because you want to simply have the speakers visible for audio only purposes? I can understand that, but it will cost you thousands more.

I just built one about 3' out. Since it's a fixed frame, I could then opt for Seymour DIY, and save a whole lot of money.

http://forums.audioholics.com/forums/showpost.php?p=767982&postcount=49

Speaking of drop-downs, Seymour, and tab tensioned, I am very impressed by the designs of Seymours.

Tab tensioning

Our patent pending stealth tab tensioning is a standard feature. We stitch on a fabric velvet border which allows us to conceal the tension tab and tension cables behind the borders. While the bottom corners at the weight bar and top near the case are visible, we've eliminated the ugly hourglass shape and huge width penalty of common tensioned designs. Most importantly, we've eliminated the absurd price penalties that other companies charge for their tension designs.

http://www.seymourav.com/screensretractable.asp

 

[slisgrinder]

Thanks for the replies guys. The acoustically transparent screen method is quite expensive and I did some calculations and found that if I place speakers about 5' from the screen (wall with drywall and special screen paint) then it works out. Or I could go the false wall method which I like at the expense of screen size but I can live with that for quality instead of quantity.

But something else did happen, my dad changed the size of the room so I have some room to play with while keeping the same screen size AND having a false wall (sort of)... Will get back with more details and sizes and possibly a google sketchup of the dimensions.

Thanks again.

 

[jostenmeat]

I don't understand why you need as much as 5', but what is great about that is more flexibility with speaker placement. I find that more space from the front wall, or closer to listener, provides the best imaging.

That said, I wouldn't call a smaller screen here a sacrifice! I also downsized with false wall, but it's great. The 144x81" you mentioned, that is a 166" screen! I looked up your PJ, and while in Dynamic mode you have the power to perhaps light it up, it will look very bad if you are a videophile with film.

The PJcentral review, after their best/favorite calibration, has it at 525 lumens, way below the 2k or so with neon-green-dynamic. A 525 lumen PJ has no business trying to light up such an enormous AT screen. Bear in mind this is in high lamp mode as well. Also bear in mind that this is a new PJ/bulb. If regular lamp mode, after a few hundred hours, that number will drop very significantly. Don't light up such a huge screen with this PJ.

Therefore, downsizing your screen is not a compromise here, but an improvement.

 

[slisgrinder]

I am not a videophile but I like to get things squared and the right size etc, but this is in a pitch black room with matte black walls, ceiling and floor. However, audio is my main concern (I prefer my audio to be near perfect) because this is not for me, but for my dad and he is hard of hearing in is right ear so I want to get him the best sound possible (thus going to build from diy plans or make and verify my own plans). In the near future, I will be changing the projector to a better one but for now it will have to do. I will get back to you guys with the new room dimensions and a sketchup once I am done with new years.

Just because I felt like sharing this, my idea for this room (which is in the basement) is to have 3-way center, left, right, maybe side speakers, and 2 way surrounds with a horn loaded sub in front and a reflex bass in the back for reinforcement. This might be overkill...

 

[jostenmeat]

I am not a videophile but I like to get things squared and the right size etc, but this is in a pitch black room with matte black walls, ceiling and floor. However, audio is my main concern (I prefer my audio to be near perfect) because this is not for me, but for my dad and he is hard of hearing in is right ear so I want to get him the best sound possible (thus going to build from diy plans or make and verify my own plans). In the near future, I will be changing the projector to a better one but for now it will have to do. I will get back to you guys with the new room dimensions and a sketchup once I am done with new years.

Just because I felt like sharing this, my idea for this room (which is in the basement) is to have 3-way center, left, right, maybe side speakers, and 2 way surrounds with a horn loaded sub in front and a reflex bass in the back for reinforcement. This might be overkill...

FWIW, three way speakers are more complex, as you know.

You will want to xover your tweeter at least as high as 2khz, and depending who you ask, even as high as 4khz or above. This of course would require a mid-driver that can remain linear at such frequencies. All of this is related to dialogue intelligibility, in regards to what may be called the critical speech discrimination band. IOW, you don't want to xover right in the middle of it.

Of course, keep them vertically arrayed, with tweeters at ear height.

Why a horn and a reflex sub? The best way is to use identical subwoofers. If you're starting from scratch, then definitely.

Check out the Tuba HT designed by Bill Fitzmaurice. You'll have to pay $15 for the plans if I recall.

For the speakers, check out the ER18 designed by Murphy (and Kittinger) of Salk fame.

 

[slisgrinder]

Awesome, thanks, then I'll go for 2 horn loaded subs, one in the front and one behind the "audience" (my dad, mom and I) something that could reach as close to 20Hz as possible. I was thinking of the "Wicked One" from Decware but then its response is better at 30Hz rather than 20. I just finished my first semester of the 2 years for Electronics technologist program here and starting Jan 10th should be getting close to learning about filters so I can design my own crossover (parallel so as not to get too complex with active amplifies for the woofers). But I will definitely check out the suggestions. The more the merrier... (I hope I spelled that right)...

 

[jostenmeat]

38% room length is the de facto starting point for your ears. Doesn't matter from front or back wall. This evens out your axial modes the best.

At the very, very least, give your self several feet from the back wall. Once you start nearing the back wall, you have to start treating it.

b pape has stated that this number may drop to low as 33% with the inclusion of nonaxial modes.

The quality of bass in particular is insanely dependent on the room, and positioning of subs and listeners. Good on you for going with multiple subs, something I've never had the pleasure of trying.

The issue with taking care of bass, overhang, modes, is that they can mask your dialogue frequencies. This is related to being to close to the back wall, where bass collects (which doesn't sound like a bad thing at first), but it masks your other frequencies.

 

[slisgrinder]

Whoa... I had to look up room modes as I am an audio n00b, not a total n00b, but n00b. I will have to dwell a bit more on that topic to adapt it to my specific room while learning along the way. I have never built my own speakers so this is just a stepping stone to my ultimate goal. I will first make small speakers for stereo or something then move onto bigger things. Thats why building by someone else's design would be a good idea if I want to learn and get some experience.

I am in the process of building a couple of workbenches and 4 shelves so getting some woodworking experience as well. I did take shop class in high school (~4-6 years ago) and I did well so got myself a miter saw from ryobi. Next on the list is a dremel set + table saw OR build a CNC mill for wood that has a working area of 4'x8' - the standard size of MDF sheets.

I need to look into room treatments as well especially for the ceiling.

 

[AVRat]

http://www.harman.com/EN-US/OurCompany/Technologyleadership/Documents/White Papers/multsubs.pdf
http://www.harman.com/EN-US/OurCompany/Technologyleadership/Documents/Calculators/Room Mode Calculator.xls
http://myhometheater.homestead.com/viewingdistancecalculator.html
http://myhometheater.homestead.com/Verticalviewing.html

 

[slisgrinder]

Awesome, thanks AVRat! Oh and Happy New Year everyone!

Still working on those dimensions so probably sometime tonight I will post them up.

 

[jostenmeat]

Whoa... I had to look up room modes as I am an audio n00b, not a total n00b, but n00b. I will have to dwell a bit more on that topic to adapt it to my specific room while learning along the way. I have never built my own speakers so this is just a stepping stone to my ultimate goal. I will first make small speakers for stereo or something then move onto bigger things. Thats why building by someone else's design would be a good idea if I want to learn and get some experience.

I am in the process of building a couple of workbenches and 4 shelves so getting some woodworking experience as well. I did take shop class in high school (~4-6 years ago) and I did well so got myself a miter saw from ryobi. Next on the list is a dremel set + table saw OR build a CNC mill for wood that has a working area of 4'x8' - the standard size of MDF sheets.

(Don't worry about being a noob. Depending on who is helping me in any given thread, I am often enough the total noob.) I would also lean towards someone else's design for my first DIY speakers. They probably won't happen for quite a while because of the cost of tools. I think I'd like a Bosch jigsaw, Porter or Milwaukee router (keep hearing different opinions between the two), a skil saw, pipe clamps (cheap, and can use different lengths of pipe with them). For a table, I'd buy a thick good piece of MDF and put them on a couple of saw horses. jinjuku taught me about the Jawhorse, there is a thread about it in the DIY forum here. Ebay has a great combo deal on them.

I need to look into room treatments as well especially for the ceiling.

One of the attributes you get with the ER18 recommendation is that it's a vertical MTM. This will reduce floor and ceiling bounce.

Awesome, thanks AVRat! Oh and Happy New Year everyone!

And same to you!

 

[slisgrinder]

I am strongly pulled towards the ER18 build cause I was just looking at them a couple of days ago. I am a sucker for upright speakers... Still working on those room dimensions...

 

[slisgrinder]

Here are the floor plans. They might be off by a few inches (as much as 6" even) as I took them off the construction plans with some calipers. The ceiling height is 92" and I tried to make it the inside dimensions so excluding all the wall frame and studs.

The screen will be on a false wall which will be 3' from the left most inner wall (the one that measures 288" from the right) I will try to make use of the small corner space (which measures 41" x 24").

 

[AVRat]

Obviously there's a door, any windows? Locations? So it's more like 24 x 16 x 7-8. Cool, big screen, area along sides for access behind.

 

[slisgrinder]

no windows in the room, will be making access to the room from the right on this floor plan or the bottom.