Riser Questions

[drpiranha]

The room I'm going to use for my home theater is 12' x 19' 8". It has new standard carpet and padding, (about 1/2' thick) which came with the home, that was just completed.

I intend to put a riser in the back of the room, the entire 12' width and 6 1/2' deep. It will be 11" high.

I will construct the riser on top of the existing carpet, and then cut away the carpet, not under the riser, and re-carpet the entire room. I will use 2 x 10's for the riser and cover it with 1 1/4" thick plywood.

Here are my 2 choices after doing the frame with (2) 12' long 2 x 10's and (2) 75" long 2 x 10's.
1. I can use 75" 2 x10's, every 12" on center and then put on the plywood or
2. I can use them every 16" on center and then use perpendicular pieces between the joists at the 25" and 50" marks. I will also do a step about 18-20" wide on one side of the room.

Obviously, the 2nd choice is more structurely sound, but is it overkill? There will be a sofa on the riser, 2 speakers about 50 lbs each, a medium size fridge, possibly a pinball machine, plus the people (3-6).

Also, since I am putting this on top of carpet, is it necessary to fill the riser with insulation. I am trying to spend as little as possible, without sacrificing a quality movie experience.

This is on the 2nd floor. All thoughts and comments would greatly be appreciated. Thanks.

 

[jostenmeat]

I intend to put a riser in the back of the room, the entire 12' width and 6 1/2' deep. It will be 11" high.

Are you SURE 11" is high enough? I'd go overkill on height for future flexibility. I'm sure you know about this calculator:
http://www.theater-calc.com/

That is for the MINIMUM height. But, as I've said before, some people actually prefer to NOT recline, and happen to have spiky hair-do's.

Also, you might not be a well versed acoustician yet, but being against or near the rear wall will have you suffer bass issues. As you learn more about acoustics, or find that you want a more immersive viewing angle, or for whatever reason, having a taller riser will give you the flexibility to move.

With the above in mind . . .

I will construct the riser on top of the existing carpet, and then cut away the carpet, not under the riser, and re-carpet the entire room. I will use 2 x 10's for the riser and cover it with 1 1/4" thick plywood.

. . . doing this will make your riser placement permanent. Why not just re-do all of the carpeting to begin with???

Here are my 2 choices after doing the frame with (2) 12' long 2 x 10's and (2) 75" long 2 x 10's.
1. I can use 75" 2 x10's, every 12" on center and then put on the plywood or
2. I can use them every 16" on center and then use perpendicular pieces between the joists at the 25" and 50" marks. I will also do a step about 18-20" wide on one side of the room.

Obviously, the 2nd choice is more structurely sound, but is it overkill? There will be a sofa on the riser, 2 speakers about 50 lbs each, a medium size fridge, possibly a pinball machine, plus the people (3-6).

Holy moly dude, that is a LOT LOT LOT of weight. 6 people, sofa, pinball machine, speakers, fridge??? Go overkill on the overkill. Mine supports 4 people + the HT seats, and I actually had to reinforce mine. Do it once, do it right, and then you don't ever have to worry about it.

Also, since I am putting this on top of carpet, is it necessary to fill the riser with insulation. I am trying to spend as little as possible, without sacrificing a quality movie experience.

As for insulation inside a multi function riser, you might want to read this thread:
http://forums.audioholics.com/forums/showthread.php?t=27511

 

[Bryce_H]

I would be concerned about the depth of your riser, particularly with everything you indicated you may have on there.

I built my riser using 2X12 around the perimeter, with 2X6 in the interior for bracing. The perimeter boards rest in u-boats to further assist in decoupling it from the floor. The riser is set off the wall by 1/2" from the wall to prevent vibrations from the riser or wall transferring to the other - particularly since you are going to have speakers on the riser. I then topped it with 3 layers of plywood screwed together offsetting the joints, with construction glue. The riser is filled with two layers of pink fiberglass insulation. In each rear corner there are 4X8 inch holes cut in the top to assist with bass (help prevent the riser from becoming a giant resonance chamber) with grills over them for safety. The top of the riser overhangs the edge by 2 inches to allow for carpet to be wrapped underneath and the installation of rope lighting. Here are some pictures:
The one with the riser lifted is after our basement flooded - but you can see the structure underneath and hte insulation

 

[drpiranha]

The reason for the post is that I am a little scared to do this and unsure of everything.

Josten, I did use the riser calculator and it came out to 10 3/4", which is why I'm doing the 11" riser.

The speakers are floor standing, so they have to be on the riser. The fridge will just be a mini one, so about 40-80 lbs, depending on the size I go with.
The pinball machine was just an idea to put back there, because I do have one. If those more informed than me, feel it's a problem, I don't have to put it back there.
Obviously, I need something to seat about 3 people, and then there is always the chance that someone else will walk back there to get something out of the fridge.
My family and friends are capable of putting this together and I can easily calculate out the dimensions of all the wood that I need.
I'm just pretty insecure about the design.

 

[jostenmeat]

The reason for the post is that I am a little scared to do this and unsure of everything.

I understand.

Josten, I did use the riser calculator and it came out to 10 3/4", which is why I'm doing the 11" riser.

As for the #s you plugged in, did you measure a tall person with spiky hair sitting upright, without recline? If not, are you planning on asking them to recline when they block or distract your view? In any case, I vote that you make it taller. Stadium seating is cool, go for it. What if you ever upgrade to a bigger display? You'll have to rebuild/reconfigure the riser. What if you kept the same screen, and wanted to move both rows two feet closer, while keeping the same screen in place? If you left no margin for flexibility, you will not be able to. JMO though on the matter.

The speakers are floor standing, so they have to be on the riser. The fridge will just be a mini one, so about 40-80 lbs, depending on the size I go with.
The pinball machine was just an idea to put back there, because I do have one. If those more informed than me, feel it's a problem, I don't have to put it back there.

If you don't have to, why would you? Don't put the fridge on it either. The floor speaker I can see, in order to get them at a better height, but make sure it won't easily get knocked over.

Perhaps, without having pics or diagram, make the riser's depth just enough for the seats themselves, and space to put your feet down. Do not make it so deep that it reaches the back wall. Place the riser away enough so that the fridge and pinball machine can simply be on the "floor".

If you have people constantly climbing onto the riser to grab a drink, it could be more distracting as you will likely feel them moving around on the riser as well.

 

[drpiranha]

Thanks for the response.
I will be retiring and most of the family won't be living with me but visiting on weekends. I am getting a 120" diagonal screen which is the largest that room really could handle.
Most of the time, the room will be used by my family and we will be sitting in recliners in front of the riser. The riser will be used when throwing a party 4 or 5 times a year. I don't know any spiky haired people, but if I meet some, they get to sit in the back.
I spent all my time thinking about room design, projector, screen, and chairs, but paid no attention to structural integrity. Since this is on the 2nd floor, it's important.
The 1st thing I will do is contact the builder and make sure I know the direction of the joists used in the floor. I will then do my joists perpendicular to that for better load bearing on the floor.
Right now I'm thinking about doing the joists on a 16" center and putting blocks in between them at the 25" and 50" points.
I did some research on weights and supports.
I have gotten the weight of all the lumber. The joists and frame are 315 lbs, the blocks are 70 lbs, and the 1 1/4" plywood is 375 lbs. This totals 760 lbs and is just under the 10 lbs/sq. ft. recommended dead weight limit. The recommended live weight limit is 40 lbs/sq. ft. which would be 3100 lbs.

A reclining sofa is about 225 lbs, the speakers are 110 lbs and 4 big people are 900 lbs. That only puts me at 1235 lbs. Theoretically, I could put a 80 lb fridge and even my 260 lb. pinball machine and be at only 1/2 of the allotted weight. I'm not sure I should do that, but the numbers indicate that it's workable.

 

[jostenmeat]

Thanks for the response.
I will be retiring and most of the family won't be living with me but visiting on weekends. I am getting a 120" diagonal screen which is the largest that room really could handle.

How far will the front row's eyes be to the screen? I'm assuming 16:9 AR. May I ask, just out of curiosity, what projector and screen you have chosen?

The room I'm going to use for my home theater is 12' x 19' 8". It has new standard carpet and padding, (about 1/2' thick) which came with the home, that was just completed.

I intend to put a riser in the back of the room, the entire 12' width and 6 1/2' deep. It will be 11" high.

I will construct the riser on top of the existing carpet, and then cut away the carpet, not under the riser, and re-carpet the entire room. I will use 2 x 10's for the riser and cover it with 1 1/4" thick plywood.

Here are my 2 choices after doing the frame with (2) 12' long 2 x 10's and (2) 75" long 2 x 10's.
1. I can use 75" 2 x10's, every 12" on center and then put on the plywood or
2. I can use them every 16" on center and then use perpendicular pieces between the joists at the 25" and 50" marks. I will also do a step about 18-20" wide on one side of the room.

I wish I could understand your descriptions. Mine is simply one big azz box, open on the bottom. I used all 2x8s. I *think* it's not even as structurally sound as even just option 1, but I put ply for extra structural support directly on the frame on all sides (but not the bottom, as aforementioned). It's completely sufficient in strength for 4 people and the seats.

 

[drpiranha]

Josten,
The back of the 1st row of seats is up against the riser, so its 13' 2" from the screen. My projector is the Epson 1080 UB and the screen I plan on getting is the FocusPix TensionFlat 16:9 Widescreen Tab Tensioned Electric Projector Screen. http://www.htdepot.com/Focupix_TensionFlat_16_9_Electric_Screen_105_p/fxt169s-120.htm

I made a trip out to the house today and talked to the construction manager.
Much to my surprise, the floor joists run the length of the room, rather than the width. That means that I should run my joists along the width of the room.

 

[jostenmeat]

Josten,
The back of the 1st row of seats is up against the riser, so its 13' 2" from the screen. My projector is the Epson 1080 UB and the screen I plan on getting is the FocusPix TensionFlat 16:9 Widescreen Tab Tensioned Electric Projector Screen. http://www.htdepot.com/Focupix_TensionFlat_16_9_Electric_Screen_105_p/fxt169s-120.htm

Cool, that's pretty much the ideal starting point for viewing angle. After playing around a LOT did I myself settle on 42 degrees, which you would obtain after scooting up the seating by about 20" or so.

You are looking for a retractable screen because you want access to windows behind it? A plasma or something? Cheers.

 

[drpiranha]

Josten,
The reason for the retractable screen is simple. I have cats and don't want them to use it as a scratching post. It's easy to watch them when I'm in the room, but I don't want to resort to closing the door every time I'm not in the room.
Oh, and thanks for all the responses. I really appreciate it.