Looking for theater design feedback...

[freejeep]

Hi All,

Just moved into a new house and I am going to build my 1st home theater in the basement. I'm currently in the planning stages and would like to get some feedback on my current design.

System will include:

Panasonic PT AE900U
92" diag 16x9 screen
Denon AVR-3805
Denon DVD-2910
Paradigm Monitor 7s - fronts
Paradigm CC-350 - center - behind screen
Paradigm ADP-350s - sides
Paradigm Mini Monitors - rears
Paradigm PS-1000 - sub

Room is 11'3 w" x 18'11"d x 6'8"h.

I'm going for a classic cinema look, with all speakers concealed (main reason for front placement). The angled rear walls are my attempt to maximize room depth while working around some existing mechanical and traffic issues. The sides and rears will be built into columns. The red stuff is curtains.

Looking for any major issues you might see in my design: speaker or projector placement (especially sub), seating location, room shape, etc.

General idea what it might look like

Thanks in advance for your feedback.

DonC

 

[j_garcia]

Looks pretty good. I like your gear choices with the exception of the sub. Definitely go with a sub from the respected sub builders like SVS and HSU because the bang for your buck is much better. Paradigm's lower subs just arent' that great to be honest.

The mains are too close to the side walls and you are going to get some major first reflections / boundary effects. You'll find that once they are installed you may need to either toe them in more or pull them a bit more toward the center to achive proper imaging. Sub location should be OK, but it's really hard to say at this point because, until you actually have it in the room, you won't know how it is going to sound.

 

[t3031999]

one thing is that you don't have any corners to place bass-traps so you may not be able to fix some acoustics problems that may arise.

just my observation.

 

[Khellandros66]

The angles in the rear are bad for acoustics, I would decide against those.

As for a Sub SVS PB12-ISD/2 would be perfect in that room if not bump up to a PB12-Plus/2

EDIT- Also grab the Denon AVR-3806 if you can, better automated setup adding the Audessy MultEQ XT, it adds Denon Link, and HDMI inputs.

~Bob

 

[bpape]

I'd agree on the bottom end. The rear angles negate the possibility of using those corners as bass absorbers and the corner sub placement in the front impedes doing floor to ceiling there.

IMO, you need to sacrifice a bit of depth and take a more realistic look at the number of GOOD seats you can put in the room. At a minimum, make the rear angles less severe and build some membrane absorbers into the rear wall and in those angles. Also, move the front wall out a bit so you have some flexibility as to where to place the sub. The corner is rarely the best choice. While it will provide the most output, it also usually produces the least smooth frequency response.

 

[freejeep]

Thanks for the feedback guys. I'm currently looking into a different configuration that would eliminate the angled rear walls. I'll post some follow-up drawings when I finalize it.

I plan on making a number of absorbers and bass traps for the room. Would it be beneficial to also leave the above floor joists exposed, stuff them with fiberglass and cover with cloth vs installing a standard drywall ceiling? Again the ceiling height is only 6'8" so there is not a whole lot of room for hanging much in the way of absorbers from a drywall ceiling.

As for the sub, I already have the PS-1000 and replacing it is not in the budget at the moment. However I will definately look at the alternatives you presented when finances allow.

Thanks again,

DonC

 

[Duffinator]

Looks great so far and you have some good suggestions from other members. Are you are using a perforated screen? If so I'd suggest moving the center channel speaker below the screen and get a solid screen. I don't have a lot of experience with this but a friend of mine has a perforated screen with an Infocus 7200 DLP projector and he complains about the grids not matching well with the perforations. I've watched many movies and I don't notice it much so maybe he's too picky. But I'd investigate this further before you buy a perforated screen. Just my $5 worth.

 

[Rob Babcock]

Even with those unconventional corners you could still place Real Traps. I'd suggest if you go with a perf screen you find the smallest microperf to avoid screen door effects. There's a company that makes screens out of material that's supposed to be as acoustically transparent as speaker cloth yet as reflectant as a normal screen, woven, no perfs. Can't recall the company name, but it seems like they've been mentioned here.

I think a Hsu or Svs sub or two would be better for the $ than Paradigm, but their subs are no slouches, either. Another name you might look into is VMPS- lots of output for the money.

That's a very nice looking theater! I'm envious.

 

[bpape]

I'd agree with Rob on the screen and the sub selection.

As for the open ceiling, you may find that this gives you too much upper mid and high frequency absorbtion - not to mention compromising the isolation both ways for the theater.

I'd do the drywall ceiling and spot treat appropriately as needed to bring the decay times down to an even level across the spectrum. The target time to shoot for will be determined by the finished volume of the space.

 

[freejeep]

OK, here's the latest and greatest...

Floor to ceiling bass traps in all four corners. The "Stage" will be more an illusion as it will be made up mostly of cloth (acoustically transparent in front of the speakers) covering a basic, open frame. More space behind the stage for more subwoofer placement options (can be moved forward a bit up under the stage as well). Drywall ceiling with absorbers placed as needed. A non-perf screen with the center channel positioned below.

The only minor issue I have is the water meter and pipes, running floor to ceiling, in the lower left corner (yellow box). Could make it difficult to palce the bass trap at a 45 degree angle in that corner.

Again, thanks for the feedback. I'm confident it will make my theatre experience that much more enjoyable.

DonC

 

[ScottMayo]

Here's something I wrote on another forum which may be of some help. These traps will NOT solve bass problems but they will help clear up imaging and damp general room ring, and they are not expensive to build.

I like your new design a lot more, but the rear seating is not going to have good acoustics. It's too close to the rear wall; even with a great deal of trapping in back, there's going to be bass boom back there, especially with the sub against the front wall. Fixing that wouldn't come cheap. I would at least delete the rear left and rear righmost chair. Good places for the popcorn maker and the soda machine - or maybe more realistically, some extra bass trapping.

Anyway, cheap HF flat traps:

---

This will build a trap that stops mostly HF frequency, and is good for 1st reflection points.

Start with some Owens Corning 703 or Roxul RXL 40, in a 2" thickness. These are the guys for it: http://www.spi-co.com. In Canada, contact Roxul for their distributor. A 2'x4' sheet is what you want - they sell them in packs.

Lay a sheet of it on the floor, and build a wood frame around it, out of cheap pine 1x4's, with the 1" face of the wood against the floor all the way around. A 1x4" is about 3.5" wide, so the wooden frame sticks up higher than the thickness of the fiberglass, by about 1.5".

Screw the frame together (I like adding L-braces inside to keep it squared) and then spray a little 3M "77" adhesive along the wood where the fiberglass touches, all the way around. Allow to dry for a few minutes.

Now get a piece of colored burlap, 3'x5'. Slide it under the frame, more or less centered, and spray the outside of the wood frame, all the way around, with the 3M glue. Pull up the edges of the cloth against the sticky sides of the wood, pulling it tight as you go.

Volia, a simple trap. Cut away excess burlap, and mount it on a wall so that the 1.5" air gap is against the wall, and the flat burlap surface is out to the room. This trap won't do a lot of bass trapping, but it efficiently eats the frequencies that affect imaging the most, so it works out well at 1st reflection points.

You can stuff the air space in back with polyester batting or foam - this doesn't change the acoustics much, and helps keep dust from escaping.

Commercial products do it better, and there are all sorts of changes you can make to this trap to get different effects. Note that 2'x4' is a little small for a 1st reflection trap - but putting 2 side by side is often plenty, if properly placed.

Pine (you don't need fine quality because none shows) is relatively cheap, and OC 703 isn't bad if you buy a bunch. A power saw capable of straight cuts, a drill, a power screwdriver, and you're there.

Note - the Roxul is mineral wool, not fiberglass. It's not as tough, a little denser, and ecologically friendly. Whichever you use, wear a dust mask when you mess with it.

Keep in mind that a normal "cubic" room with 2 speakers has 12 reflection points. You might or might not want to go after them all; the effect varies.

 

[freejeep]

Final (maybe) design

Hi All,

Been working on the design for a while, and here is what I hope will be my final design (front, rear and sub placement are still being analyzed):

I've addressed all previous concerns as best I could based on room constraints. I purchased Cara room analyzer, and so far the initial results have been pretty good.

Also, I picked up a Yamaha RX-V2500 and DVD-S2500 rather than the Denon units. Couldn't justify large difference in price between these and the 3805 and 2910 units.

Let me know what you think.

Thanks,

DonC

 

[voicebox5]

What kind of acoustic treatments will you be using?

Depending on the type of walls and flooring you have, it will be important to set up some sound dampening, whether it be acoustic tiles or special paint. Auralex has products ranging from complete room systems to individual pieces. Looks good so far! Good luck with everything!