# Designing House with HT in Basement



## John2010 (Mar 19, 2010)

Hello,

I am new to this site and have spent a lot of time looking at different threads and have read different opinions on what to have. Since I am designing my house, and the basement is wide open to any dimensions I want, I figured I would just post a question. I have included a proposed layout of where the HT would go and its dimensions. The room will have 3 sides of 2.5" insulated concrete walls with the back wall being 2x6, the room size is 9'x15'x20' (HxWxL). I would like either 2 rows of 3 to 4 seats.

Questions:
1) Is this size room okay?
2) What size or how big of a screen can I go (would like 120")
3) How far from screen should the 1st row seating be?
4) How far in between the seats?
5) How tall of a platform do I need for the 2nd row?
6) Is 7.1 an overkill?
7) Should I stud the concrete wall and add additional insulation?

Any additional information will greatly be appreciated.


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## bpape (Sep 14, 2006)

Welcome

1) Is this size room okay?
**** Not bad. I might consider going a little bit longer - maybe 21-22' just to stay farther away from double the height. Also gives you a little more play with the 2 rows.

2) What size or how big of a screen can I go (would like 120")
**** Depends on whether you do an AT screen or not. Are you talking about 120" WIDE or diagonal? What aspect ratio are you considering? In general, without AT, that's going to push your speakers pretty close to the side walls. That can be dealt with via treatment.


3) How far from screen should the 1st row seating be?
**** Seating distance has nothing to do with the screen. It's purely a function of the length of the room. General rule of thumb is 1st row is 62-665 of the length for best bottom end response. Then size the screen accordingly to get the minimum THX recommended 36 degree included viewing angle. NEVER let the screen size drive seating position. That's backward.

4) How far in between the seats?
**** As close as you can get to stay as far from the rear wall as you can. Leave room for reclining of both rows.

5) How tall of a platform do I need for the 2nd row?
**** Depends on exact screen size, aspect ratio, mounting height, and seating distances. Basically, you just need the rear row to see over the front row's heads. Now, if you do 3 seats in front and 4 in back, you won't have heads right behind each other and you can get by with something a little shorter potentially.

6) Is 7.1 an overkill?
**** Not at all.

7) Should I stud the concrete wall and add additional insulation
**** Absolutely. Before you start, think very carefully about isolation of sound getting out of the room and sound getting into the room. There are things to do during construction that can help a lot with those areas.

Welcome to the madness.

Bryan


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## John2010 (Mar 19, 2010)

Hey thanks for the welcome... its a madness I am willing to become a part of 

http://www.hometheatershack.com/forums/images/smilies/rofl.gif

1) Is this size room okay?

**** Not bad. I might consider going a little bit longer - maybe 21-22' just to stay farther away from double the height. Also gives you a little more play with the 2 rows.

# I will play with the length, but if I add additional insulation to the width, my 15' now become 14', and if I bring the length to 21' then I believe I will achieve a 1 : 1.6 : 2.33 ratio (seen this on another thread)

2) What size or how big of a screen can I go (would like 120")
**** Depends on whether you do an AT screen or not. Are you talking about 120" WIDE or diagonal? What aspect ratio are you considering? In general, without AT, that's going to push your speakers pretty close to the side walls. That can be dealt with via treatment.

# Yes, I was referring to 120" diagonal with a 16:9 ratio (unless this should all be different). I do not know what AT means? Also, this room will have no windows.


3) How far from screen should the 1st row seating be?
**** Seating distance has nothing to do with the screen. It's purely a function of the length of the room. General rule of thumb is 1st row is 62-665 of the length for best bottom end response. Then size the screen accordingly to get the minimum THX recommended 36 degree included viewing angle. NEVER let the screen size drive seating position. That's backward.

# Based on the room dimensions (20', 21' or 22' what would be the best THX distance?

4) How far in between the seats?
**** As close as you can get to stay as far from the rear wall as you can. Leave room for reclining of both rows.

# Fair enough on this response.

5) How tall of a platform do I need for the 2nd row?
**** Depends on exact screen size, aspect ratio, mounting height, and seating distances. Basically, you just need the rear row to see over the front row's heads. Now, if you do 3 seats in front and 4 in back, you won't have heads right behind each other and you can get by with something a little shorter potentially.

# Did not think about 3 & 4 combo for seating, could I add a 3rd row either in front (2 seats) or in back (5 seats) or will the length I am working with prevent a 3rd row. Also is a 3rd row even needed?

6) Is 7.1 an overkill?
**** Not at all.

# Fair enough

7) Should I stud the concrete wall and add additional insulation
**** Absolutely. Before you start, think very carefully about isolation of sound getting out of the room and sound getting into the room. There are things to do during construction that can help a lot with those areas.

# Where can I look to find out what I can due during construction. The wall materials will be a 2.5 in insulation block with 6" concrete poured in between. This makes the house house air and sound tight. But I guess anything extra won't hurt.


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## bpape (Sep 14, 2006)

The insulated block will do nothing to stop sound from getting up into the floor above you. 

AT is Acoustically Transparent where you put the speakers actually behind the screen.

Again, don't let screen drive the seating. Put the seats where they need to be and adjust screen size accordingly. This refers to #3. The included angle starts from your center front seating position and extends out to the edges of the screen. As your room gets bigger, the seats move back proportionately which makes the intersection of the angle at the edge of the screen larger.

This is fine but remember that without the AT screen, this also pushes the side speakers even closer to the walls.

I would not recommend 3 rows in a room that length.

For construction, I'll be happy to walk you through things. If your concrete to concrete width is 15' and not changeable, you should lose approx 11" of width (assumes 1" air to frame, 3.5" frame, 2x1/2" drywall = 5.5" per side if my math is correct)

Bryan


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## SierraMikeBravo (Jul 1, 2007)

Make sure the frame to concrete wall meets code. Too much space could result in a code inspector requiring you to redo the framing. It is a fire issue since the spacing could act as a chimney if too far spaced and not within code. Best wishes!


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## bpape (Sep 14, 2006)

Agreed. Since you're trying to save space anyway, you probably weren't thinking of a big space. 1" at most and you should be fine. Even 1/2" will work.

Bryan


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## John2010 (Mar 19, 2010)

Hey guys thanks for the info.

Can I assume that the AT screen is better and more costly?

I have been looking at my basement layout and could also have another spot at 15' x 24'-ish.

Also check out the arxx website (its the name then instead of com its net)

I do not have enough posts to add a webpage... still a newbie.


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## John2010 (Mar 19, 2010)

Hey sorry forgot to add in last post that the 15' in width is actually finished to finished wall


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## bpape (Sep 14, 2006)

The AT will cost more - especially to get a good one like an SMX, Stewart, or Screen Research. SMX will be the most affordable of those 3 but IMO, the best performing too (take whatever bias you want since I'm an SMX dealer). Any of those 3 will very handily outperform other AT screens from an audio and video standpoint.

Are they better? Well, they're different. They won't have a ton of gain so you have to watch size and brightness. On the other hand, they do provide a much better screen lock and allow better spacing of the speakers from the side boundaries - hence a larger potential screen without causing problems as long as the PJ has enough output with the lower gain.

Bryan


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## SierraMikeBravo (Jul 1, 2007)

I think you'll find a variety of opinions regarding screens. The Stewart Studiotek 130 AT is considered the reference and my personal recommendatiion, but don't worry about equipment as yet. Worry about getting the room done right...then see what it takes to fill it to reference standards. Best wishes!


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## bbieger (Sep 15, 2009)

I have a Seymour AT screen that I am very very pleased with. Stay away from the perforated screens, go with a weave. 

I made my own frame and stapled the fabric to it. Very cost effective. The screen material was around $225 custom cut and shipped to my door.

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

the owner is a member here and a very nice guy. Give them a call to ask questions.


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## DougMac (Jan 24, 2008)

I've built a similar sized HT and can attest the advice you're getting here is spot on. I have little to add other than I consider your depth minimal for two rows, especially if you're shooting for a 120" diagonal screen, which is what we have. It's amazing how small the room gets when you start adding seating.

There's another consideration regarding depth if you consider going with an acoustically transparent screen. You have to push the screen out into the room to get the speakers behind it. This can be as much as 2' or more, depending on the depth of the speakers and if they have rear firing ports. For instance, 6 inches between back of speaker and walls, 18" speaker cab depth, plus 4-6" spacing between screen and front of speaker. That puts the screen 2 1/2 feet from the wall.


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## bbieger (Sep 15, 2009)

That is a very good point Doug. I have 2'behind my screen. Pretty cramped behind there..3' would have been nicer.

Love the look at sound of the at screen though for sure!


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