# Riser height...?



## Meldge (Dec 6, 2011)

Hi Guys and Gals,

I'm wanting to start building the riser for the 2nd row of seats. The 2nd row are theatre recliners with front row going to be 2 x 2 seaters (standard couches, not yet bought) they will be angled in slightly with a gap in the middle for steps onto the riser.

I'm looking at building the riser in 3 sections plus 2 angled sections for the angle on the front row, once purchased. At this point the rear outer sections I'd like to build first. The middle section will be a 15cu ft box:yikes: for a 15" subwoofer.

With all of that in mind, knowing a 15" sub will be hidden in the middle section here is my dilemma. I would want the riser to be about 15 - 16" in height, this will allow enough room for two steps up to the riser. Is this too high though? :dontknow:

My room is 4 metres wide and just over 6 metres long? What are your thoughts people as I'd like to go and purchase some timber...? :dontknow:

I'll try and draw a rough sketch on the PC and attach when I can to help you see it.
Also, the screen is 3 metres wide. :T


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## ALMFamily (Oct 19, 2011)

How high is the ceiling?


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## tonyvdb (Sep 5, 2007)

Yup, ceiling height is going to be the only real factor here. if 16" is going to make a person hit the ceiling with their head then that not going to be a good idea at all and actually unsafe and in some places illegal. there should be at least 6ft between the top of the riser and the ceiling.


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## Meldge (Dec 6, 2011)

Roof is 7.8ft high (2400mm).

Leaning the Tempest so it rests on it's magnet and basket (angled) it sits at about 350mm (1.1ft) in height, tipping it back to approx 45 degrees only gains me about 10 - 15mm saved height and also closes up the vent gap more which I'd prefer not to do.

I'm about 6'2". Between my head and ceiling, roughly 1.8ft (550mm)
That gap then would leave about 215mm between myself and the ceiling. 

I could angle the subwoofer face back and build the box to about 350 - 375 in height, but then I'd still need to incorporate the timber thickness for the riser, then carpet which still takes it up to roughly 400mm. :doh:

I really want to build this sub into the riser as a 15cu ft box is hard to hide elsewhere.

Does the above make sense or not...?
Rough top-down sketch done but I can't attach it...


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## Meldge (Dec 6, 2011)

I don't know if this is going to work...
I added a description whilst uploading it...

Edit, here's the description:

Purple and Red - Riser area.
Red - Sub box.
Green angled wedges - Built later dependant on lounges purchased.
Yellow - Couches.
Black at top - Screen.

Cinema chairs not drawn on.
Exact measurements of purple not yet defined, need to move chairs in to see how much room is need whilst they are reclined.

Read more: Home Theater - Image Gallery - Extremely rough concept - Top


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## ALMFamily (Oct 19, 2011)

I really like the concept, but I am not certain it will work. When building a stage with plans for the subs to be located on it, you are supposed to fill it with sand to better absorb the vibrations and not have a resonant effect (?). Attempting to fill the riser with sand and keep the sub "clean" might be risky business.

Another thing to consider - if you have a projector, where are you mounting it and will it's location cause you headroom problems as well?


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## Meldge (Dec 6, 2011)

Cool, glad someone else likes the concept.:bigsmile:

It will all be on carpet and I was thinking of using insulation in the side pieces. The current projector sits right at the back of the room, so even standing with your legs against the chair you still won't hit it. That PJ is dying though so I'll have to make sure I can mount the next one in the same spot. 

Just reminded me, I'm going to open the projector and try and find the problem, there is some shading on one side of the image, looks almost like some film layer is peeling up or something.

I could build a box with the Tempest with the DS8 plate amp and sell it I suppose, there is a young fellow at work that is keen on it.

I could then build the side portions of the box as the woofer boxes and go for two of them. The room is 4 metres wide and the chair is only 3.1ish, so I could use that extra space in the corners to do a dual setup and have the sub mounted in that spare area and that would allow me to drop the height a little I guess. Just an idea, but it means buying and selling more stuff though.

But yeah, was going to insulate the side sections, and maybe have the build the sides after building the box so that I can match the height and the box can be held in place firmly with the riser top and couch.


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## bpape (Sep 14, 2006)

What if......

You raised the riser only behind the rear row and had the drivers firing forward instead? Or angled. That would give you a lot of cubic footage - say 18" up behind the rear row, 16" deep, and full riser width?

That would let you keep the seating portion of the riser at a more reasonable height with more headroom.

Bryan

Bryan


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## Mike P. (Apr 6, 2007)

If the back row of recliners are 15+ inches away from the wall then another option would be up fire the Tempest-X at the back and port it out the front. This would allow you to lower the riser to gain more headroom. Nice sub and amp combination by the way. :T


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## Meldge (Dec 6, 2011)

Mike P. said:


> If the back row of recliners are 15+ inches away from the wall then another option would be up fire the Tempest-X at the back and port it out the front. This would allow you to lower the riser to gain more headroom.
> 
> View attachment 34488


Yeah I am still tossing up with that idea as well, and I understand the acoustical build up if the seats are too close to the wall so it would be a benefit in more than one area. I am trying to keep the seating from being too close to the screen, especially with the front seating being angled the ends will be closer to the screen again.

I'd like to angle the front row as this is still our main living room and seating where you can see the other people is preferential from a conversation point of view.



Mike P. said:


> Nice sub and amp combination by the way. :T
> 
> View attachment 34488


Yeah, I went off someones word that they would work well together. :whistling:


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## Mike P. (Apr 6, 2007)

Alright, I just remembered who you are. :heehee:


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## Meldge (Dec 6, 2011)

Mike P. said:


> Alright, I just remembered who you are. :heehee:


:rofl:

That is still an option though.

If I were to use 90mm pipe for the ports how many and what length would you recommend?
I'm also going to look into some larger pipe (possibly 150mm) that I have seen around the place, will get measurements of that one as well.

PS - 15hz tune 15cu ft box.

I was looking into slot ports as well so maybe a measurement for two ports, one at either end of the box, IF you don't mind that is... :dontknow:


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## Mike P. (Apr 6, 2007)

90 mm - you need 4, each being 730 mm long.

150 mm - you need 2, each being 1000 mm long.

two slot ports - each are 50mm high x 250 mm wide x 700 mm long.


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## bpape (Sep 14, 2006)

Going back a few posts about seating too close to screen, I'll reiterate....

Seating location for good sound comes first. Then you select a screen size that is appropriate for your projector, throw range, brightness, and seating positions. Trying to fudge seating to fit a screen that is too big is only going to cost more money and give lower performance in the long run.

Bryan


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## Meldge (Dec 6, 2011)

Mike P. said:


> 90 mm - you need 4, each being 730 mm long.
> 
> 150 mm - you need 2, each being 1000 mm long.
> 
> two slot ports - each are 50mm high x 250 mm wide x 700 mm long.


You are a legend...:T


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