Riser Frame construction ? - AVS | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!


Forum Jump: 
 3Likes
  • 2 Post By BIGmouthinDC
  • 1 Post By BIGmouthinDC
Thread Tools
post #1 of 29 Old 10-11-2014, 03:50 AM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Question Riser Frame construction ?

Hi,

I'm building a riser for my second row. It will be 30 cm (1 foot) high, 120x220 cm (4x7feet).

I will be using OSB for top/side. It is not clear to me however what is the best design for the inner frame: should it be a closed box-like (including struts/beams on floor) or built like a chair with "legs". I do not mind wasting a bit of work/wood if it makes it more sturdy.

Does anyone has a drawing/picture of the inside frame of a raiser ??

Last edited by doctorG4; 10-11-2014 at 05:01 AM. Reason: wrong unit conversion!!!
doctorG4 is online now  
Sponsored Links
Advertisement
 
post #2 of 29 Old 10-11-2014, 04:29 AM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 22,419
Mentioned: 26 Post(s)
Tagged: 3 Thread(s)
Quoted: 1013 Post(s)
Liked: 968
first think of a deck hanging off the back of your house, build the frame just like that with long legs then cover it with a skin so you can't see under it. So to answer your question, Chair with legs, with exterior skirting to look like a closed box.
BIGmouthinDC is online now  
post #3 of 29 Old 10-11-2014, 04:31 AM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 22,419
Mentioned: 26 Post(s)
Tagged: 3 Thread(s)
Quoted: 1013 Post(s)
Liked: 968
A riser that high is going need a railing. Are you sure 4ft deep is enough for your seating and an ample walkway? Got to say I've never seen a riser that high.
BIGmouthinDC is online now  
post #4 of 29 Old 10-11-2014, 04:50 AM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Quote:
Originally Posted by BIGmouthinDC View Post
A riser that high is going need a railing. Are you sure 4ft deep is enough for your seating and an ample walkway? Got to say I've never seen a riser that high.
The original post had incorrect unit conversion!! It was 1 foot not 3.

Thanks for the answer on the construction. The reason I asked if joists needed to be connected horizontally on the floor as well is exactly because it is indeed a high raiser so I think I need some stringer somewhere half height to give some torsion rigidity (maybe diagonal ?)

30 cm height comes from the calculator and simple geometry. The first row head height is 1.25 cm and the distance between two rows is 1.16 cm. I tried sitting on a chair and the riser height needed is correct to clearly see the screen. The size of the aisle is approx 50 cm which is OK with the chairs on floor.

I have plenty of this woolly glass fiber insulation material left over from walls. Should I also fill the raiser with it to avoid drum effect ?
Attached Thumbnails
Click image for larger version

Name:	Screen Shot 2014-10-11 at 13.37.49 .png
Views:	85
Size:	77.7 KB
ID:	305458   Click image for larger version

Name:	2014-10-01 09.26.00.jpg
Views:	96
Size:	75.7 KB
ID:	305522  

Last edited by doctorG4; 10-11-2014 at 05:01 AM.
doctorG4 is online now  
post #5 of 29 Old 10-11-2014, 09:39 AM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 22,419
Mentioned: 26 Post(s)
Tagged: 3 Thread(s)
Quoted: 1013 Post(s)
Liked: 968
for a foot high riser, I would build the perimeter out of 2x12s which are 11 1/4 inches tall. Think of building a sandbox just a perimeter box of the 2x12s. Then put 2x8s stringers spanning the short distance front to back simply hanging off the front and back 2x12. That should be strong enough but if it has too much spring add mid span supports, Cover the riser with two layers of 3/4 plywood or OSB board (Chip board)

Pictures from a foot high riser, I used 2x10 stringers but you can use 2x8s or 2x6s for your size riser.
Attached Thumbnails
Click image for larger version

Name:	IMG_0020.jpg
Views:	212
Size:	194.5 KB
ID:	305850   Click image for larger version

Name:	IMG_0028.jpg
Views:	194
Size:	132.7 KB
ID:	305858   Click image for larger version

Name:	IMG_0301.jpg
Views:	182
Size:	148.7 KB
ID:	305866   Click image for larger version

Name:	IMG_0909.jpg
Views:	189
Size:	145.8 KB
ID:	305874   Click image for larger version

Name:	IMG_1018.jpg
Views:	222
Size:	249.8 KB
ID:	305882  

mikela and doctorG4 like this.
BIGmouthinDC is online now  
post #6 of 29 Old 10-11-2014, 03:35 PM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Great thanks!
Is there any advantage building the raiser up to the back wall vs stopping immediately after the last row and leave a 40 cm/1.5 feet lane at normal floor height ?


Inviato dal mio iPhone utilizzando Tapatalk
doctorG4 is online now  
post #7 of 29 Old 10-11-2014, 06:04 PM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 22,419
Mentioned: 26 Post(s)
Tagged: 3 Thread(s)
Quoted: 1013 Post(s)
Liked: 968
cleaning and safety.
doctorG4 likes this.
BIGmouthinDC is online now  
post #8 of 29 Old 10-11-2014, 09:14 PM
Member
 
Bill97Z's Avatar
 
Join Date: Oct 2005
Posts: 163
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked: 10
Quote:
Originally Posted by BIGmouthinDC View Post
for a foot high riser, I would build the perimeter out of 2x12s which are 11 1/4 inches tall. Think of building a sandbox just a perimeter box of the 2x12s. Then put 2x8s stringers spanning the short distance front to back simply hanging off the front and back 2x12. That should be strong enough but if it has too much spring add mid span supports, Cover the riser with two layers of 3/4 plywood or OSB board (Chip board)

Pictures from a foot high riser, I used 2x10 stringers but you can use 2x8s or 2x6s for your size riser.
Where did you get that "fake" arm for your love seat?
Bill97Z is offline  
post #9 of 29 Old 10-12-2014, 03:24 AM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 22,419
Mentioned: 26 Post(s)
Tagged: 3 Thread(s)
Quoted: 1013 Post(s)
Liked: 968
it is a feature of the Fusion line of seating. Rtheaters.com. RSH on the forum. It has a fin that slides down between the seats that holds it in position.
BIGmouthinDC is online now  
post #10 of 29 Old 10-12-2014, 03:39 AM
AVS Special Member
 
blah450's Avatar
 
Join Date: Jan 2010
Posts: 1,039
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Liked: 130
Quote:
Originally Posted by BIGmouthinDC View Post
for a foot high riser, I would build the perimeter out of 2x12s which are 11 1/4 inches tall. Think of building a sandbox just a perimeter box of the 2x12s. Then put 2x8s stringers spanning the short distance front to back simply hanging off the front and back 2x12. That should be strong enough but if it has too much spring add mid span supports, Cover the riser with two layers of 3/4 plywood or OSB board (Chip board)

Pictures from a foot high riser, I used 2x10 stringers but you can use 2x8s or 2x6s for your size riser.
Of course, AWESOME finished HT, BIG.

Why the blocks attached mid-joist?


edit: never mind...i now see they extend down until flush with floor for additional support.
blah450 is offline  
post #11 of 29 Old 10-12-2014, 09:35 AM
AVS Special Member
 
ctviggen's Avatar
 
Join Date: Dec 2003
Posts: 1,995
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
Liked: 20
Why the insulation but no way for sound to get into the riser? Or can sound get under the front?

Bob
ctviggen is offline  
post #12 of 29 Old 10-13-2014, 01:36 AM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Quote:
Originally Posted by ctviggen View Post
Why the insulation but no way for sound to get into the riser? Or can sound get under the front?
The acoustic vibration will be transmitted anyway via the walls of the enclosure so the riser will resonate at drum frequencies, that is why insulation will dampen it and reduce internal resonances. Of course if there were holes in the riser that will make it more effective to "capture" and dampen the sound (mostly low freq).

In my case I'm not so in favour of punching holes in the riser, I'm not convinced that the effectiveness of riser as bass trap outweight the hassle of making the holes, put nice grill/acoustic fabric on it etc but I might be wrong here..
doctorG4 is online now  
post #13 of 29 Old 10-13-2014, 05:16 AM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 22,419
Mentioned: 26 Post(s)
Tagged: 3 Thread(s)
Quoted: 1013 Post(s)
Liked: 968
Quote:
Originally Posted by ctviggen View Post
Why the insulation but no way for sound to get into the riser? Or can sound get under the front?
they just don't show in my pictures
BIGmouthinDC is online now  
post #14 of 29 Old 10-14-2014, 12:47 AM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
OK. Thanks to all comments. I have started the construction...:-)

Regarding bass trapping should I really do something for this (i.e. holes somewhere)
or is my plan to simply fill it all with insulation enough ?
Attached Thumbnails
Click image for larger version

Name:	2014-10-14 08.20.48.jpg
Views:	99
Size:	126.7 KB
ID:	310762   Click image for larger version

Name:	2014-10-14 08.21.11.jpg
Views:	92
Size:	118.2 KB
ID:	310770   Click image for larger version

Name:	2014-10-14 08.21.26.jpg
Views:	91
Size:	93.9 KB
ID:	310778  
doctorG4 is online now  
post #15 of 29 Old 10-14-2014, 08:11 AM
Advanced Member
 
rprice54's Avatar
 
Join Date: Apr 2005
Posts: 571
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Liked: 43
starting my riser this week, I'll tag along for the ride. I like the 2x12s with 2x8 stringers idea for my 14'x7' riser.
rprice54 is offline  
post #16 of 29 Old 10-15-2014, 01:19 AM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Question Riser: work in progress

OK here the frame completed.

I'm still missing reinforcements on the place where I will screw in my cinema chairs.

Can Jeff or anybody comment on how to make holes and cover them for making a bass trap ? Which size ? which position ?
Attached Thumbnails
Click image for larger version

Name:	2014-10-15 09.11.52.jpg
Views:	93
Size:	167.1 KB
ID:	312418  
doctorG4 is online now  
post #17 of 29 Old 10-15-2014, 05:21 AM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 22,419
Mentioned: 26 Post(s)
Tagged: 3 Thread(s)
Quoted: 1013 Post(s)
Liked: 968
There are two schools of thought on the holes. One is to place them at the wall riser instersections. The other is on the front face. The wall riser placement ususally uses 4x36 or 4x48 inch grills. The calculations of size and whether you have the required volume is something beyond my training.
BIGmouthinDC is online now  
post #18 of 29 Old 10-15-2014, 07:20 AM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
I found in meanwhile tons of posts (sic!) regarding how to turn a riser in a bass trap which have been interesting to read with fanatic followers armed with acustic spectrum analysers and so....;-)
(see Riser Bass Trap, not against walls)

Anyway 2 basic methods:

A) Helmholz Resonator (complicate as it needs to be tuned to specific frequencies with same kind of calculations like is done when building a loudspeaker). I discarded investigating this as results from forum all seemed bot complicate and ineffective.

B) Broad band absorbers, working of principle to dampen (i.e. not reflect) any inpinging acoustic (bass) wave, basically a big box full of suitable absorbers (glasswool or similar) with holes. Also here there is alot of theory, but basically the space under the raiser should not be partitioned but open to allow the absorber to do its work.

With my frame design (which is open with horizontal and vertical struts, the only thing I have to do is to put grating. It has been suggested to use aluminium HVAC ones which indeed can be found for good price, so I will put 2-3 in front and 2-3 on the back (on the floor). Which also has the side benefit to allow me to access some electrical socket that happens to be there should I need it.
Doing it is cheap, if it does work good, otherwise not a big deal.
Attached Thumbnails
Click image for larger version

Name:	2014-10-15 09.11.52.jpg
Views:	44
Size:	173.6 KB
ID:	312658  

Last edited by doctorG4; 10-16-2014 at 01:28 AM. Reason: typo
doctorG4 is online now  
post #19 of 29 Old 10-15-2014, 07:42 AM
Advanced Member
 
rprice54's Avatar
 
Join Date: Apr 2005
Posts: 571
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Liked: 43
Wouldn't carpet be considered acoustically transparent- it passes the breath test. I'm wondering if I shouldn't cut holes in the platform and face, but then just install carpet over said holes. I would have to make sure they don't put pad over those holes. It would be a cleaner look as opposed to a bunch of AC register vents. I could take my 4" hole saw and go along the perimeter of the platform against the walls.

Thoughts?
rprice54 is offline  
post #20 of 29 Old 10-15-2014, 11:30 PM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
I have read of others doing exactly that. Simple circular holes 10 cm diameter. It would indeed be simpler...


Inviato dal mio iPhone utilizzando Tapatalk

Last edited by doctorG4; 10-16-2014 at 01:22 AM.
doctorG4 is online now  
post #21 of 29 Old 10-16-2014, 01:27 AM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Last night I cut the OSB boards for the top to check the position of the seats stands so I can put a reinforcement underneath and while I wait for dust to settle on best approach for holes to build a bass trap.
Attached Thumbnails
Click image for larger version

Name:	2014-10-16 08.52.57.jpg
Views:	89
Size:	74.9 KB
ID:	314434   Click image for larger version

Name:	2014-10-16 08.52.40.jpg
Views:	85
Size:	80.2 KB
ID:	314442  
doctorG4 is online now  
post #22 of 29 Old 10-16-2014, 05:55 AM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 22,419
Mentioned: 26 Post(s)
Tagged: 3 Thread(s)
Quoted: 1013 Post(s)
Liked: 968
One ticket for seat 12 please.
BIGmouthinDC is online now  
post #23 of 29 Old 10-18-2014, 02:50 PM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Not yet..:-)


Inviato dal mio iPhone utilizzando Tapatalk
doctorG4 is online now  
post #24 of 29 Old 10-18-2014, 02:52 PM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Click image for larger version

Name:	ImageUploadedByTapatalk1413669103.905936.jpg
Views:	71
Size:	271.5 KB
ID:	318850

Completed the sides.. The making of the step proves not to be trivial...thinking...


Inviato dal mio iPhone utilizzando Tapatalk
doctorG4 is online now  
post #25 of 29 Old 03-10-2015, 01:14 AM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Now that I completed my soffits and the installation of Atmos speaker on ceiling I'm back to my riser...

I decided to put some vents on the back side (against the wall) some 3 times 10x30 cm and to open circular holes 10cm diameter on the front side. This should allow basses to get into the riser and be absorbed by the glassfiber/rockfiber filling. I do not know how effective will be but In any case it will at least avoid the raiser becoming a resonating drum.


Inviato dal mio iPhone utilizzando Tapatalk
doctorG4 is online now  
post #26 of 29 Old 03-15-2015, 04:29 PM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Today big progress, opening and grids done, filled with glasswool/rockwool done....

Click image for larger version

Name:	ImageUploadedByTapatalk1426462069.008536.jpg
Views:	38
Size:	327.6 KB
ID:	604505Click image for larger version

Name:	ImageUploadedByTapatalk1426462090.008279.jpg
Views:	42
Size:	328.6 KB
ID:	604513Click image for larger version

Name:	ImageUploadedByTapatalk1426462106.960414.jpg
Views:	30
Size:	291.9 KB
ID:	604521


Inviato dal mio iPhone utilizzando Tapatalk
doctorG4 is online now  
post #27 of 29 Old 03-15-2015, 04:31 PM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Riser Frame construction ?

Forgot the photo of the grids near the back wall

Click image for larger version

Name:	ImageUploadedByTapatalk1426462240.001586.jpg
Views:	32
Size:	345.5 KB
ID:	604529


Inviato dal mio iPhone utilizzando Tapatalk
doctorG4 is online now  
post #28 of 29 Old 05-02-2015, 01:24 PM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Completed the top and carpet being place on the riser. Working slowly but progressing..
.Click image for larger version

Name:	ImageUploadedByTapatalk1430598181.032784.jpg
Views:	22
Size:	317.7 KB
ID:	697322


Inviato dal mio iPhone utilizzando Tapatalk
doctorG4 is online now  
post #29 of 29 Unread Today, 03:51 PM - Thread Starter
Member
 
doctorG4's Avatar
 
Join Date: Jan 2005
Location: Netherlands
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Liked: 11
Carpet layed on the floor and surround speaker mounted.

To be continued..
Click image for larger version

Name:	ImageUploadedByTapatalk1430952608.401599.jpg
Views:	3
Size:	239.5 KB
ID:	703442


Inviato dal mio iPhone utilizzando Tapatalk
doctorG4 is online now  
Sponsored Links
Advertisement
 
Reply Dedicated Theater Design & Construction

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off