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Posted By: Danno Newbie Home Theater Room Size Question - 09/28/06 01:52 PM
Hello, all! I've been reading about Axiom speakers for a long time, but just discovered your forums. I'm new to the home theater world, and am currently planning on building a dedicated HT in my basement. I have a question on room size. I will be working with one side of our finished basement. Two of the dimensions of the theater will be fixed since I'll be working with existing walls: The ceiling is 7' with a tongue and groove drop ceiling already installed. The width is 10'4'" with paneling that I plan to paint and treat with curtains and/or acoustic panels as needed. However, I have almost complete freedom as to the length of the theater; I just need to decide where to build the back wall. I was reading about the 'golden ratios' for room size. Some of these calculations give an approx. 16' length. I was thinking more of 20' or so. Based on my existing height and width, any opinions on the length I should go with? I plan on using a front projector/pull-down screen set-up for the video. For audio, I'm planning on floorstanding M60s or M80s with sub, surrounds, etc.

Any ideas or opinions on how long my theater should be would be appreciated. I'll be working on building/finishing the room this fall/winter, but need to decide the dimensions.

Thanks all!
Posted By: michael_d Re: Newbie Home Theater Room Size Question - 09/28/06 02:16 PM
Howdy....

Mine’s 12’ wide by 16’ deep and it’s too damn small. My next HT will be 16’ wide and 24’ deep.

You will have to decide if you want one or two rows of seats first. But if you go with a single row, I’d still make it a minimum of 20’ in length just so you have room for proper 7.1 speaker placement, furniture placement, your equipment and storage.
Posted By: dllewel Re: Newbie Home Theater Room Size Question - 09/28/06 05:33 PM
Mine is 13' x 24. I wish it was a little wider, but works well. If you are limited by the 10'4" dimension, don't make the length a multiple of that (i.e. 20' 8"). Make it 23' or 24' if you want 2 rows. You'll need the space. Or 16' is fine if you are doing only one row.
Posted By: SirQuack Re: Newbie Home Theater Room Size Question - 09/28/06 06:12 PM
Mine is 15ft x 31ft, that opens into an overall 31ft x 30ft x 9ft room. First row is 13ft back, followed by a second row on a platform. Behind that is all the kids toys and walkout door/windows.
Posted By: JohnK Re: Newbie Home Theater Room Size Question - 09/29/06 03:00 AM
Danno, welcome. If possible, avoid having the length almost exactly twice the width(or three times the height), since that ratio leads to a unfavorable concentration of room modes. 18' or 23' would be suitable lengths from that standpoint.
Posted By: bridgman Re: Newbie Home Theater Room Size Question - 09/29/06 12:27 PM
I played around with Modecalc (which you can download from the RealTraps site) and found that 17.5 feet and 25-26 feet seemed to give the best distribution of room modes.


Posted By: Danno Re: Newbie Home Theater Room Size Question - 09/29/06 12:51 PM
Thanks, all! I was planning on two rows of seating, so it looks like I'll go with approx. 23-25 feet.

I'll keep reading and learning from your forum, and I'm sure you'll hear from me as my project moves along.
Posted By: michael_d Re: Newbie Home Theater Room Size Question - 09/29/06 02:00 PM
If you decide to go 23-25’, stick with 24 or slightly less. When building, always try to stay in four foot increments as all sheet goods come in four foot incremental lengths. Plus your framing is in four foot increments. If you go slightly over that four foot rule, you’ll cause yourself a lot of grief and wasted costs.
Posted By: Hutzal Re: Newbie Home Theater Room Size Question - 09/29/06 03:15 PM
Quote:

If you decide to go 23-25’, stick with 24 or slightly less. When building, always try to stay in four foot increments as all sheet goods come in four foot incremental lengths. Plus your framing is in four foot increments. If you go slightly over that four foot rule, you’ll cause yourself a lot of grief and wasted costs.




Heed this advise! My room was EVEN incriments and we had very stupid problems drywalling! TO be fair it was something like 14'5" long and 16'wide, so needless to say we had to make more drywall creases then desired.

Also, if you are starting from scratch, I would advise using staggering studs in a 2 x 6 on all walls to increase the STC factor of your room.

Here is a little article I found in staggering studs. In the end you will loose 1" of space between walls compared to using regular 2x4s, but the benefit you gain is substantial.

-Robb.
Posted By: bridgman Re: Newbie Home Theater Room Size Question - 09/29/06 04:37 PM
That's a good article and a pretty neat site.
Posted By: Slitman Re: Newbie Home Theater Room Size Question - 10/01/06 06:35 AM
Welcome Danno ! I'm in the same newbie boat as you with regards to construction of my HT. I must have lucked out .. didn't really know there was an ideal lxwxh ratio so to speak.

My dimensions are roughly 24'long (to front of wet bar) x 11'5" wide x 7'5" high.
Posted By: Danno Re: Newbie Home Theater Room Size Question - 10/02/06 12:13 PM
Well, I don't know if this is the wisest approach, but three of the four walls in the area I'm converting is already studded and has paneling on it. I was planning on just priming and painting the paneling, building the new 4th wall the same way, then add acoustic panels at the appropriate places if needed. I was hoping to avoid the drywall dust/mess. I know there is insulation underneath the paneling, so I would think that would help with the acoustics a bit. I did this with a spare bedroom in the basement, added chair rail molding all around, and it looks pretty good (the grooves in the paneling actually added to the aesthetics.) I’m not sure how good/bad this would be for acoustics in a theater room, though.

Any thoughts on this approach?
Posted By: Hutzal Re: Newbie Home Theater Room Size Question - 10/02/06 01:42 PM
Quote:

Well, I don't know if this is the wisest approach, but three of the four walls in the area I'm converting is already studded and has paneling on it. I was planning on just priming and painting the paneling, building the new 4th wall the same way, then add acoustic panels at the appropriate places if needed. I was hoping to avoid the drywall dust/mess. I know there is insulation underneath the paneling, so I would think that would help with the acoustics a bit. I did this with a spare bedroom in the basement, added chair rail molding all around, and it looks pretty good (the grooves in the paneling actually added to the aesthetics.) I’m not sure how good/bad this would be for acoustics in a theater room, though.

Any thoughts on this approach?




Danno,

The Staggered stud approach is only for sound transmission. If the majority of the room is already framed then there is not much you can do about it. If you are concerned about sound traveling to other areas of the house, I would recommend greengluecompany.com which is what I will be using on the ceiling of my home theatre. It adds an unbelievable sound transmision class for very cheap depending on your square footage that needs to be covered. Although it would reqire adding another layer of drywall on all your walls.

Acoustics can be taken care of easily with well placed bass traps in every corner and absorbtion panels on the first reflection zones. This is all done after you have all your equipment so don't worry about getting it done now!

Sounds like you have everything under control!

-Robb
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