or Connect
AVS › AVS Forum › Home Entertainment & Theater Builder › Dedicated Theater Design & Construction › Deadline Has Been Set (and Re-Set...) Theater Build
New Posts  All Forums:Forum Nav:

Deadline Has Been Set (and Re-Set...) Theater Build - Page 8

post #211 of 534
I've always been told it has something to do with the drying process and planing. But the conspiracy theorist in me likes your answer biggrin.gif

Gear mentioned in this thread:

post #212 of 534
Quote:
Originally Posted by HopefulFred View Post

If you're selling 15/32" instead of 1/2", you save a little on each one and the average customer thinks "that'll do." And it will do, in general - but it doesn't make it the same.

And perhaps it isn't 15/32" - if you check closely, then perhaps it's 12mm. wink.gif
post #213 of 534
Thread Starter 
Doing my Black Friday shopping early. Ordered the Panny 8000 from Amazon today along with a Peerless mount. Will probably order the sub this afternoon...
post #214 of 534
You hear anything out of Jamestown about your screen? I ordered mine back on the 10th of October and still can't get any word on whether it has shipped or not. Supposedly it was going to be completed by the end of last week (nearly two weeks after it was quoted to be done). Have emailed them but will call if it isn't sitting on my porch when I get home today.
post #215 of 534
Thread Starter 
Hey vanice. I haven't heard anything either. Think I'll try to get ahold of him this afternoon. Thanks for the reminder!

EDIT: Just called him. They are running behind. He said my order will ship by the end of the month now. I ordered on 10-29.
Edited by GWCR - 11/21/12 at 11:48am
post #216 of 534
Dang. Sorry to hear. Doesn't give me a warm fuzzy feeling about mine showing up this week. Crossing my fingers that it is there otherwise he will be getting a phone call from me too. rolleyes.gif
post #217 of 534
Thread Starter 
Yeah, I'm not to bent out of shape about it yet. I still have to finish the stage and screen wall anyway. If it was one of the last things on the list, that would be a different story. Glad i ordered it when I did...
post #218 of 534
Thread Starter 
Finished up the curve and step on the stage this evening.

Curve
IMG_3820.jpg

IMG_3821.jpg

Step
IMG_3822.jpg

IMG_3823.jpg

Lot's of family activities over the holiday weekend, so this will be all the work I do until next week. Looks like there's a sand storm in the extended forecast...rolleyes.gif

Have a great Thanksgiving everyone!!
post #219 of 534
good job... see it was not to bad to do rolleyes.gif
post #220 of 534
Thread Starter 
Thanks snickers. Yep. Not too bad at all. Even as a one person job. Thanks for your help in pushing me past my stalling phase.
post #221 of 534
How well did the 3/8" bend? I had some 1/2" left over but kept breaking it when trying to get it to curve. I tried kerfing(?) it but it would then just break along one of the kerfs. My span is shorter (47" both ways) so perhaps thats why I'm having so much trouble.
post #222 of 534
Quote:
Originally Posted by GWCR View Post

Thanks snickers. Yep. Not too bad at all. Even as a one person job. Thanks for your help in pushing me past my stalling phase.

any time

now you get to fill it with sand ha ha ha ha ....
post #223 of 534
Nice work. Beach time! tongue.gif
post #224 of 534
Thread Starter 
Quote:
Originally Posted by blipszyc View Post

How well did the 3/8" bend? I had some 1/2" left over but kept breaking it when trying to get it to curve. I tried kerfing(?) it but it would then just break along one of the kerfs. My span is shorter (47" both ways) so perhaps thats why I'm having so much trouble.
I wouldn't call it easy, but it bent without breaking anywhere. I followed the "pre-bend" that was already there...tongue.gif. Honestly, I can't imagine bending the 1/2" for that short a distance.
post #225 of 534
Thread Starter 
Quote:
Originally Posted by snickers1 View Post

any time
now you get to fill it with sand ha ha ha ha ....
Quote:
Originally Posted by vanice View Post

Nice work. Beach time! tongue.gif

Yeah, but I have a 15 year old who thinks he is strong. Time for him to earn his room and board! biggrin.gif
post #226 of 534
Looks good! What are you planning to layer on top of the stage?
Looking at the date on the calendar it looks like you may have to rename your thread tongue.gif
post #227 of 534
Thread Starter 
Thanks 235. I'm going to use 2 layers of 5/8 (19/32) OSB. I've seen people use either roofing felt or GG between the layers. I have both, so not sure which I will use yet (maybe both?).

The good thing about non-work related deadlines is, if you miss one, you get to set a new one rolleyes.gif New deadline is to be functional for my youngest to have a birthday party movie showing in there in mid-December. So the thread gets to keep its name, it's just the deadline that changes! biggrin.gif
post #228 of 534
Quote:
Originally Posted by GWCR View Post

Thanks 235. I'm going to use 2 layers of 5/8 (19/32) OSB. I've seen people use either roofing felt or GG between the layers. I have both, so not sure which I will use yet (maybe both?).

I wouldn't think you would want to use both. I'm guessing you would want the GG to adhere to both pieces of wood. I know that early on it was recommended to use roofing felt, but more people are going the GG route now. I recently finished my stage and am really glad I went with the sand, 2 layers of 3/4" OSB with GG between layers. It is as solid as a rock and barely makes a thump when you jump on it. If you have the GG already, I would recommend going that route.
post #229 of 534
Roofing felt is cheaper. The idea is to prevent wood to wood squeaks.

And if for any reason you ever need access to the sand, roofing felt again wins.
post #230 of 534
Quote:
Originally Posted by NGiovas View Post

It is as solid as a rock and barely makes a thump when you jump on it.

Well, that's feelgood for sure, but isn't it overkill vs just using the proper soft feet below the speakers? If you're using spikes I can understand why you'd need to dead dampen it.
post #231 of 534
Soft feet and rubber mats under a subwoofer will reduce, but not eliminate, energy (vibratory) transfer to the structure. Once that energy is in the structure it will manifest itself in walls, cabinets, floors, etc. which end up with the same resonance frequency. Equally to the point, as the motor moves forward/backward the cabinet will move backward/forward ... that ol' equal but opposite problem. When the cabinet moves in the opposite direction of the motor, that movement can, and will, reduce the effectiveness of the sub, if not its "crisp" response to the input signal. Subs, particularily high output/low frequency capable, need to be very firmly anchored to mass at least an order of magnitude greater than that of the sub. That mass needs to be reasonably isolated from the structure of the house. When mounted to a raised stage/platform, cavity resonance within that stage/platform should be reduced or eliminated. Sand is inexpensive, highly effective in absorbing vibratory resonances, and creates the high mass platform.

Green Glue between decking layers is preferred to roofing felt. Roofing felt was one of several different items used prior to the general and commercial availability of viscoelastic damping agents for CLD applications.
post #232 of 534
Thread Starter 
^^^ That's the answer I was looking for. GG it is. Thanks Dennis!!
post #233 of 534
Quote:
Originally Posted by Dennis Erskine View Post

Soft feet and rubber mats under a subwoofer will reduce, but not eliminate, energy (vibratory) transfer to the structure.

Properly tuned soft feet will make it quite difficult to measure any energy transfer. Wrongly tuned soft feet will of course be less efficient
Quote:
Equally to the point, as the motor moves forward/backward the cabinet will move backward/forward ... that ol' equal but opposite problem. When the cabinet moves in the opposite direction of the motor, that movement can, and will, reduce the effectiveness of the sub, if not its "crisp" response to the input signal. Subs, particularily high output/low frequency capable, need to be very firmly anchored to mass at least an order of magnitude greater than that of the sub. That mass needs to be reasonably isolated from the structure of the house. When mounted to a raised stage/platform, cavity resonance within that stage/platform should be reduced or eliminated. Sand is inexpensive, highly effective in absorbing vibratory resonances, and creates the high mass platform.

Well, Newton's Third at work here. But what you stated is somewhat off. It's not the weight of the subwoofer you have to calculate with - it's the moving mass of the cone. And the factor that the cabinet needs to oughtweigh that mass is approximately x1000, so three orders. Making sure subwoofer cabinets are heavy enough is quite possible, say for a 10" subwoofer with an Mmd at 30grams... that gives a cabinet weighing in at 30kg (~60 pounds). (Which is the weight of my 12" subwoofer cabinets, so they may be slightly on the light side)
Now, if people at attaching the speakers firmly to the stage, then that can count as part of the cabinet. Can't say I have seen anyone glue or drill speakers into the floor in any threads, though... If spikes or similar are used - then we still have a rocking system on top of the stage with a movement much more resonant than the small half-period movement on soft feet. Even just standing it flat on surface can induce a rocking movement pivoting around back/front edges of cabinet.

With properly tuned soft feet, I mean the kind you have to weigh the speakers both in front and back in case you need different stiffness due to the weight difference. I need to have my scales out and weigh front/back on my fronts - I only have the total weight presently...
Edited by Nightlord - 11/24/12 at 7:23am
post #234 of 534
Thread Starter 
After doing some math, it looks like I will need 67 bags of sand for the stage. If it wasn't so cold, I'd be sweating already...tongue.gif
post #235 of 534
Quote:
Originally Posted by GWCR View Post

After doing some math, it looks like I will need 67 bags of sand for the stage. If it wasn't so cold, I'd be sweating already...tongue.gif

You don't have to carry them all at once, y'know.wink.gifbiggrin.gif
post #236 of 534
Quote:
Originally Posted by GWCR View Post

After doing some math, it looks like I will need 67 bags of sand for the stage. If it wasn't so cold, I'd be sweating already...tongue.gif

67?? i filled every bit of my stage including the front step and i think yours is a little over 12ft wide? if so mine stage is also built like yours and is almost 16ft wide and i used a total of 60 bags ...... so i would think you be some where in the 50 or so bag range ?
post #237 of 534
Thread Starter 
That's what I thought too when I first did the calculations. Better to have another set of eyes on the math than to buy 17 extra bags of sand, so here it goes (all measurements are inside dimensions).



Large rectangles in back of stage 33"x14.4"x11.25"=5,383.125 in3. There are 9 of those (counting the middle split) so that is 48,448.125 in3

Curve are estimates, but based on middle depth so should be close.
9"x5.5"x11.25"=556.875 x 2 = 1,113.75 in3
8"x5"x11.25"=450 x 2 = 900 in3
7"x6.5"x11.25"=511.875 x 2 = 1,023.75 in3
5.5"x12"x11.25"=742.5 x 2 = 1,485 in3

Front corner rectangles 13"x9"x11.25"=1,316.25 x 2 = 2,632.5 in3

Front triangles 13"x13"x11.25"=1,901.25 in3

So totaling all that up I get 57,504.375 cubic inches of space to be filled with sand. One cubic foot is 1,728 cubic inches so 57,504.375/1,728=33.28 cubic feet of sand needed. 0.5 cubic feet per bag = 66.56 bags.

I would be REALLY happy if someone can point out a math error that would decrease the number of bags, but unfortunately I think my math is good tongue.gif
post #238 of 534
I ended up needing almost 70 bags for my stage which is the same design as yours. My stage is 147" wide x 57 1/2" deep. Looks like mine may be a little deeper than yours. I think your number is going to be close. You won't be able to fill each cavity perfectly because of the plastic lining but there will also be some spillage here and there. It's worth having an extra bag or two if it means not having to run back and forth to the store. I think I made three sand runs to finish mine. rolleyes.gif
post #239 of 534
I built your stage in CAD and came up with a volume of 68701.603 in^3. After subtracting an estimate for the boards within the stage, I came up with about 68 bags. So yeah, your estimate is pretty good. cool.gif

Snickers, I think I remember that you used 2x10s to frame your stage? If yes then that is likely why the numbers are a little off.
Edited by aaustin - 11/29/12 at 7:59am
post #240 of 534
Thread Starter 
vanice, my stage is 148" wide, and 52" deep at the sides. Center of step is at 54", so very similar indeed. I hear ya on the back and forth. I wonder how many extra miles and more time I added due to those trips!

Austin, I always expect you to take it up a notch. Should have asked you to build it in CAD and give me the dimensions prior to the build tongue.gif Thanks for plugging in the numbers!

Going to start with 67 and see what happens...
New Posts  All Forums:Forum Nav:
  Return Home

Gear mentioned in this thread:

AVS › AVS Forum › Home Entertainment & Theater Builder › Dedicated Theater Design & Construction › Deadline Has Been Set (and Re-Set...) Theater Build