# Room Size Help (Basement)



## VicTVRoom (Dec 19, 2009)

Ok this is my first home theater. My basement room is somewhat set in size but I have not started the framing yet so I will be able to make some changes. I have seen the .xls to help in room size but I do not get it? 

Ceiling is 7 Ft 8" which I plan on using drywall
Width is 10Ft 3 "
Lenght is 21 Ft

I can change the Length of the room not not really the width. The back of the room Width is set but the front of the room is not so I have read on this forum that you shoud make the room NOT at right angels. Other items I was planning for the room was to put in 2 rows of seating with a step up for the rear seats and maybe a platform at the front of the room. 

Any help would be GREAT.:huh:


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## tonyvdb (Sep 5, 2007)

Welcome to the Shack.

There is nothing wrong with your room dimensions I would just leave it. The back row of seating should be about 3' from the back wall to allow for the rear speakers to be placed properly and for reduction in hearing reflection off the back wall for the people sitting in the back row.
A platform in the front is good to raise the front speakers a bit so the imaging and highs are better heard in the back row.


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## bpape (Sep 14, 2006)

Hi Vic. Welcome to The Shack

Not sure what you mean about not making the room at right angles. If you mean angling the walls, you honestly don't have enough width to make it work. Not worth losing the space.

While the length of the room is pretty close to double the width, wanting 2 rows, I wouldn't shorten it any. You'd have to lose almost 3' to make it worthwhile and I don't think that's advisable.

Plan on 1st row ears being at approx 12'9" from the front wall. 2nd row as far from the rear wall as you can get without causing interference problems with the front row if/when reclining.

Screen size should be determined by those seating distances and using a minimum included viewing angle of 36 degrees for the first row. This may cause a small issue give the narrow width potentially pushing the main speakers too close to the side walls unless you're planning on an AT screen.

Welcome to the madness!

Bryan


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## VicTVRoom (Dec 19, 2009)

1st thanks for the fast answers. So I will keep the room the size the way it is. After drywall is done and the front and rear platforms are build I plan on using carpet and some type of sound Acoustical treatments for the room I have seen a lot about acoustic bass traps I guess I will need one and if so where does it go?


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## tonyvdb (Sep 5, 2007)

Bass traps usually go in the front corners of the room but placement of the sub should happen first as this will sometimes determine if you even need them after the furniture and other treatments are in place.
Bryan touched on this in his post but make sure that you keep your speakers out of the corners of the room particularly the front main channels. My personal preference is no closer than 2' from the side wall. This avoids reflection off the side walls cancelling out what is coming from the speaker and messes up the imaging of the front speakers.


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## bpape (Sep 14, 2006)

From an acoustics standpoint, you'll need to address:

Broadband bass control (more than 1 will be needed)

Side wall reflections

Front wall

General decay time balancing.

Agreed that you should tweak the sub and speaker positioning first to get the best response. Bass traps will be required regardless of any frequency response abnormalities from a decay time/ringing/masking of dialog standpoint. The frequency response itself may not require anything specific like nulls off the back wall, modal issues due to the height (both very likely), etc.

Bryan


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## VicTVRoom (Dec 19, 2009)

So based on the suggestions of the seat placement what size screen? It appears that a 83 to 101" screen would work in this space? Plus should I assume that in all 4 corners I should but floor to ceiling Bass traps?


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## bpape (Sep 14, 2006)

What is your preference for sitting in a theater? I prefer to sit mid theater but in my HT room, I sit about 9' from a 92" screen. At a 12' viewing distace, the min THX screen WIDTH would be approx 86"

Bass control floor to ceiling in the corners is a good start. There may be other specific places it needs to be addressed for specific frequency response issues as I pointed out above.

Bryan


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