Conceptuals, would love comments

[formspace]

Hello again.
From the info i've gathered so far from this great site, i've come up with a concept. Here's the renderings and diagrams so far. I'd really appreciate some comments. It's a tiered design, with 2 foot drops from tier to tier. My project outline is to make the most "theatre" for the least amount of money. I'd really like to concentrate on construction elements, DIY elements where possible, and acoustics from a design standpoint. I have a tremendous amount of volume to play with, so i am interested in doing something cutting edge, acoustically design wise. For example, i have a room, inside dims 16' by 23.3' by approx 10 feet, with a tiered floor that follows about a 19 degree incline. The ceiling slopes up away from the stage at a 9.46 degree angle.
The theatre room is about 3,728 cu feet.
Underneath that, i have about 2050 cubic feet to do whatever is necessary acoustic wise. I can have access to the floor system indefinately, and can design whatever construction is necessary into the floor system, wall system, ceiling, etc. It's still in the design stage, and the home has not broken ground yet. My questions are:
What can be done to do trapping within the construction. While mid/hi traps are part of the finish, as per the conceptuals, what wall, floor, riser, or ceiling construction could be constructed as functioning bass traps, just by adding elements ?
what can be done with the huge volume under the floor as far as acoustics is concerned? i used to make bandpass enclosures for my subwoofers, and suddenly realized that something similar would be possible, but have no idea how this would work.
I love the idea of spending minimally on equipment, and having the design of the room bring out the best of what we get.
thanks in advance for your comments and suggestions. By the way, i can offer rendering and drafting for other members interested in seeing how their theatre will visualize.

[bpape]

It's nice to have that much space to play with. There are a ton of things that can be done. There are a couple of things that I'd reconsider though...

- I wouldn't do 2' between tiers. That's going to make it extremely difficult to get all 3 rows to have decent lines of sight vertically

- For the subs, if you have room to build them in and have access to the underside (and isolation to the outside isn't an issue) I'd consider using the spaces for a nice IB setup. I'd avoid bandpass. While nice in a car setup, they're way too peaky for home theater.

Be realistic in screen size. Wiht 3 rows in a room that length, from the front row you're going to see every screen artifact there is in terms of perf screen moire, screen door effect from a digital PJ, etc. IMO 2 nice rows is a better solution but 3 can be done.

I like the multi-panel look but understand that some of them would likely be built 'empty' and just for looks. Also, I don't see provisions for any broadband bass absorbtion unless you plan do do it only behind the false front wall.

Bryan

[Sonnie]

Yeah... this could be a super nice setup when you get done. I would say it's super important to plan it out well.

I believe I'll have to agree with Bryan on the front row. It appears it will be almost too close to the screen. If you kept your screen size down to 96" diagonal, you could get as close as about 8' from the screen and probably be okay, but that is still a little close for me. I would also want to keep my back row out from the rear wall several feet.

For the subwoofer setup, IB is definitely something to consider. Also check out Rodny's IB Makeover thread for an interesting LLT concept.

Keep us posted on your design...

[formspace]

Thanks for the comments fellas.
Yes, realizing that designing a theatre is exactly like designing everything else, basically it's an equation of compromise. Basically, i'm setting up for a good middle and front row acoustically, both at 38%. The back row is definately the cheap seats, but there's room and budget allows. Although 2 foot tiers might not be ideal, part of the design is allowing access to the basement in the space allowed, hence the steepness. I have to work out the screen parameters, any rules of thumb? As the seating also reclines, trying to find the ideal view for all seats is quite difficult. I'm thinking about adjustability, one setup for full theatre, another for just middle row, using masking and a track for the PJ. Perhaps even adjustable angles on the screen, but of course i also want to keep it as simple as possible.
What i'd like to figure out first though is how i could potentially incorporate bass trapping into the construction of the walls, floors and ceiling so i can at least finalize the structural drawings.

[brucek]

Basically, i'm setting up for a good middle and front row acoustically

From where you have your mains positioned and pointing, I think the front row will get a poor result.

You might consider moving them more toward the screen wall.

Also, I don't see any back channel speakers. Are you not going to be using a 7.1 setup?

brucek

[formspace]

You are right brucek, i'm finding it hard to be both clear and succinct. (compromise...) basically, the program for the theatre is thus: 80 percent of the time, 2 people will be in the theatre. (middle row, most likely. That is why all the speakers are equidistant from this point, represented by the circle) 10 percent of the time, 4 people. Again, say middle row. 8 percent, 8 people. (mid and front) and 2 percent, more than 8 people. (full theatre.) Which is why i'm compromising between the ideal for the middle row, and acceptable other places. Re: 7.1, i was under the impression that the size didn't warrant it, but would be interested in viewpoints. It'll have to be wired for 7.1 in any case for future considerations.
But all that is a ways down the road. I'm still trying to finalize the construction details of the room itself.

[Hakka]

What software did you use for those renderings?

Looks good.

Hakka.

[formspace]

Thanks
This one was done with 3ds Max to take advantage of it's lighting analysis.
Would like to find another tool that can do the acoustical analysis, if one exists.

[John Simpson]

Looks fantastic Derek -- 3DSMax is a wonderful program. It's interesting to see the soft effect of the indirect lighting behind the wall panels. Did you minimise environment lighting and use ray tracing?

Certainly, your front speakers are in the wrong place. I'd be more inclined to sit them up against (or close to) the front wall... get as much distance between them and the front seats as you can. The whole "speakers in a circle" thing is fine, but only if you sit at the centre of the circle!

Why not drop out the front row altogether? Do you need that many seats? Then you could increase your screensize, and place the front speakers behind it.

Oh, and you would be mad *not* to use an infinite baffle sub for this room. Read into it a bit more and you'll understand why... :holycow:

[John Simpson]

Oh, and one other thing: a room this size should use at least a 7.1 setup, preferrably 9.1. You'll want an encompassing soundstage, and not one that is obviously front/rear.

Even if you can't buy the speakers/processor for it now, at least wire it all up and just use the two rear speakers in 5.1 as a temporary measure.

[John Simpson]

Hahah, just thought of something else.

Bryan is spot-on about the height of those risers -- on the weekend we saw Transformers in one the posh "Gold Class" cinemas here in Australia. When the seats reclined, the angle needed to tilt your head forward was actually a little uncomfortable (I reverted the seat to upright and just used the footrest).

You may have to do some tests with seats and big boxes to work out what's comfortable for you, before you start building.

I do believe I'm quite excited about your project. Keep us up-to-date!

[bpape]

I'd definitely do 7.1. 9.1 is doable with some tweaking.

Speakers absolutely need to go more toward the front. You might want to consider a small false wall, a good AT screen, and some quality inwalls like Snells or Triads. That will give good audio to video presentation for all rows.

If you want to set up the screen for front and middle row, then the screen will be lower and the top row will have eyes at or above the top of the screen which will present PJ issues for throw angle. Setting it up for middle and rear (screen higher) will put the PJ right and make the front row more like a real theater where you're just looking up all the time. Recliners help here though (recommend motorized)

Bryan

[formspace]

Thanks for the info fellas.
Good eye John, that was raytracing only. No global illum at all. I'm amazed how the raytracing carries the colour of the material, as the walls are actually a yellow colour, but the ray tracing reflects the back of the panels which are covered in the red.
re: the 7.1, 90 percent of the time, or perhaps more, the middle row only will be used. The additional seating is there for those rare occasions that the theatre will be used for demonstrating stuntwork/ filming to movie industry execs. Can anyone point me to an article about the benefits of 7.1 in this type of setup? Is 7.1 better even if it's only 2 people in the theatre? I was under the impression that this was not the case, but am admittedly ignorant in this regard.
I am striving for crisp, clean, echoless acoustics for the 90 percent of the time, mid circle, two people in theatre kinda deal with a compromise all other times, concentrating on acoustical design rather than expensive equipment.
The screen/ recliner setup is definately a headscratcher. I believe that the screen and pj will have to be movable and maskable to solve this satisfactorally. Good call on the mockups, they are worth their time in gold.

[Anthony]

I use CARA (http://www.cara.de/ENU/index.html) for acoustic analysis. Way more powerful than anything I've done with it, but it takes some time to set up and run.

Renderings are nowhere near as good and 3D Studio, but you get the general gist. It is extremely helpful for finding room modes, standing waves, first reflections, etc.

It also has a great speaker placement tool. I once spent a whole weekend doing sweeps and moving my subwoofer around to find the best location. I modeled my room (L shaped with level changes) in CARA and it told me the EXACT same location I found experimentally. The predicted frequency response was almost spot on too.

So powerful tool, not too expensive ($100 to $200 IIRC).

Great work so far and good luck!

Anthony

formspace wrote:

Thanks
This one was done with 3ds Max to take advantage of it's lighting analysis.
Would like to find another tool that can do the acoustical analysis, if one exists.

[SierraMikeBravo]

There are a few free programs out there to create a first order idea of your room modes. This is used to get an idea of where to place your seating in speakers. Preferably you want to keep the seats out of the first and second harmonic nulls for the length. This will place your seating in the third harmonic peak, but you can compensate for that by placing the speakers in the null of the third harmonic. Keep in mind that placing your front speakers right along the wall will place them in the peak for all of your room resonances. This will excite all of them and result in boomy bass especially between 150Hz and 300Hz. The best thing to do is place your seats, then build your room around them. You can thus play with the room dimensions to reach the best compromise of your setup. This is assuming that you are working with a blank basement. If you need a program that gives the room modes, let me know, I created one using excel. Not toom difficult to understand. The aesthetics look great! However, the way you currently have it setup, it will sound terrible. It is amazing the differences in room acoustics with a few modifications. In addition, it looks like the room will be quite dead with all the panels you have in the drawing. My suggestion if you wish to have all those panels is to not treat them. Basically have wrapped fiberboard or plywood or something reflective. Treating the room that much will completely kill all of your highs and will actually change your room modes as well if you use thick enough insulation. I would look more into construction (studs..insulation..etc.) for some treatment and isolation. Also, don't forget that your most important frequencies to tame are 300Hz and below not the high ones. Those are quite easily taken care of especially if you are using and Audessey RoomEQ built into a good receiver (or seperates...Lexicon comes to mind). Audessey basically rolls off the highs, but you may have to treat the room just a little to avoid harsh initial off axis reflections.

For the video aspect, if you are going to sit that close, you absolutely must have a 1080p projector using either blue ray or HD DVD. This is the only way you will get the pixels to be small enough for closer viewing.