IB in a 6000 cuft HT (27L x 22W x 10H) - AVS Forum
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post #1 of 27 Old 10-21-2012, 11:22 AM - Thread Starter
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SEE UPDATED PICS BELOW (12-14-2012)




Hi all!

I had posted a thread in the Dedicated Theater Design & Construction forum (a month or so ago) seeking advice on potential bass trap ideas for the HT I will be building once our home is complete.

Here is the opening statement from that thread :
"...We are having a new home built. Once the home is completed I will begin finishing the basement. One portion of this basement is under one of the garages (the 3 car) so it will have a SpanCrete ceiling. The whole theater will be a sarcophagus of concrete making for some great isolation. I have been planning this new build for the last 12 months or so..."


I already have Eight 18" Fi IB318's and also Two 15" Dayton Titanic MkIII's. I have attached a link to the most current iteration of my design so far.

The front baffle/screen wall will still have the eight 18" Fi IB318's mounted in a sorta stepped shelf which will protrude about 1 foot into the room (it will be about 25" high). The front baffle will be angled in slightly on each side with four drivers per side. The left side "room" will have the 19" rack (in red). The left side "room" is just a void but built in to add symmetry and give additional air space for the IB side.

At the rear of the room in each corner will be bass traps 6' wide floor to ceiling (filled with regular fiberglass insulation). The lower portion on each side will have a built in 11ft3 ported 15" Dayton Titanic sub tuned to 20hz. These would act as filler subs to help tame some bass peaks (hopefully).

My plan is to go with a Denon AVR-4520 which has Audyssey MultEQ XT32 which provides equalization for two separate subwoofers.

Anyone see anything wrong with this current idea?

Thanks in advance,
Rob

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #2 of 27 Old 10-23-2012, 12:51 PM
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The biggest problem I see with that design is making a baffle strong enough to handle the vibrations of a 8X18" line array. Have you thought about a manifold? It would help to reduce the structural vibrations significantly. How much back space do you have for the IB? I used 4 of the FI IB18's with about 500 Cu ft.

Another thing to keep in mind is that concrete does conduct mechanical vibrations fairly well. I would make sure none of your room framing comes in contact with the concrete (room within a room) and would even suggest additional soundproofing methods. My theater room is surrounded on 3 sides with concrete, but I still built a room within a room with 3 layers (2 layers of drywall and a layer of OSB. I did the same thing for the IB chamber. The soundproofing efforts were the best thing I spent money on. The best aspect is that it lowers your noise floor so much that you can hear details like whispers without having to turn it up. The noise floor of your room has a huge effect on the dynamic range. I rarely miss dialog in the theater but do all the time when watching elsewhere.
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post #3 of 27 Old 10-23-2012, 12:54 PM
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One other thing - I had initially planned to do a couple extra subs to augment the bass. I really doubt that 2 15's are going to be able to correct any nulls from 8 18's unless they are pushed to their max to try and keep up, or the IB is throttled back. In other words, the capability of the 15's are going to be the limiting factor in the system.
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post #4 of 27 Old 10-23-2012, 02:14 PM - Thread Starter
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Quote:
Originally Posted by stockmonkey2000 View Post

The biggest problem I see with that design is making a baffle strong enough to handle the vibrations of a 8X18" line array. Have you thought about a manifold? It would help to reduce the structural vibrations significantly. How much back space do you have for the IB? I used 4 of the FI IB18's with about 500 Cu ft.
Another thing to keep in mind is that concrete does conduct mechanical vibrations fairly well. I would make sure none of your room framing comes in contact with the concrete (room within a room) and would even suggest additional soundproofing methods. My theater room is surrounded on 3 sides with concrete, but I still built a room within a room with 3 layers (2 layers of drywall and a layer of OSB. I did the same thing for the IB chamber. The soundproofing efforts were the best thing I spent money on. The best aspect is that it lowers your noise floor so much that you can hear details like whispers without having to turn it up. The noise floor of your room has a huge effect on the dynamic range. I rarely miss dialog in the theater but do all the time when watching elsewhere.

I'm not worried about noise due to the fact that this entire portion of the basement is under the 3 car garage. No adjacent walls to any living space. Not that it matters but this room is also 2 feet deeper than the rest of the basement too (12ft vs 10ft).

The air volume behind the baffle wall coupled with the additional air space in the chamber on the right side of drawing provide a bit over 10x's VAS. I have attached a drawing of how I plan on building the front wall & baffle :

th_FrontWall.jpg

All lumber will be secured to one another and the concrete via construction adhesive and nails. I think it will be plenty sturdy, but my drawing is here to be looked at by all and critiqued! Any advice/suggestions WELCOMED!

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #5 of 27 Old 10-23-2012, 04:13 PM - Thread Starter
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Quote:
Originally Posted by stockmonkey2000 View Post

One other thing - I had initially planned to do a couple extra subs to augment the bass. I really doubt that 2 15's are going to be able to correct any nulls from 8 18's unless they are pushed to their max to try and keep up, or the IB is throttled back. In other words, the capability of the 15's are going to be the limiting factor in the system.

I know they wont be able to keep up at all, I was simply hoping that they would provide some sort of benefit to taming some peaks caused by the front 18's. Would I be better off not installing the 15's?? Depending on budget I may be able to put two more Titanic 15's (for a total of two per side in the rear). Pointless???

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #6 of 27 Old 10-26-2012, 06:56 AM
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Rooms with stiff boundaries are prone to lumpy bass, but you have an ideal layout for 4x two-driver opposed manifolds placed at the 1/4 width and height positions on the screen wall. Manifolds help tame vibration from the drivers; wall position will help tame width and height room modes. Your traps should help with the remaining modes.

If you decide to stick with the line at the floor/wall boundary intersection, consider adding 2x6s from the top of the driver positions angled back down to the floor to be certain the drivers can't move.

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post #7 of 27 Old 10-26-2012, 10:59 AM
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I've had a 4 driver array (18" Ascendant Audio Avalanche) in the front wall of my living room next to the ceiling for 5 or so years. There's never been any wall flex or paint cracking. Arrays are just fine IF braced properly.

120@20@14'
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post #8 of 27 Old 10-27-2012, 05:59 AM - Thread Starter
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Thanks Paul so much for the input.

I'm not too worried about flex, but your suggestion sounds like it would have a substantial benefit to helping room modes by having the drivers spaced in that manner. Of course I could be completely off base too.

BTW, I didn't realize who you were until I clicked your link. I have run across your room (web page) several time in the past while researching my new upcoming project. Also FOH had given me your link too over on The Cult as a good reference! Small world, I mean web.....

Thanks Paul,
Rob

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #9 of 27 Old 10-27-2012, 10:28 AM
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If you are going to do the 15s in the back... I know you will lose a bit of output but I would put them in sealed boxes, a much better match with the IB subs. I attempted running 2 lesser ported subs with my IB for a while, never could get them to mate well and in the end the SQ and umph was way better with only the IB playing.... only strong as the weakest link sort of thing, I suppose. This is just my experience, every case is a bit different.

-RMB

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post #10 of 27 Old 10-27-2012, 12:25 PM - Thread Starter
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Quote:
Originally Posted by Rmb1080p View Post

If you are going to do the 15s in the back... I know you will lose a bit of output but I would put them in sealed boxes, a much better match with the IB subs. I attempted running 2 lesser ported subs with my IB for a while, never could get them to mate well and in the end the SQ and umph was way better with only the IB playing.... only strong as the weakest link sort of thing, I suppose. This is just my experience, every case is a bit different.
-RMB


I should have mentioned earlier that making the 15's sealed (vs. ported) was suggested earlier to me over on The Cult. I am now toying with 4 of the 18's along the bottom baffle, a pair of manifolds (w/2 18's each) located higher and to the sides of the screen wall and 2, possibly 4 15's in the rear corners hidden inside the bass traps.

Thanks.

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #11 of 27 Old 10-27-2012, 02:07 PM
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If you have 4 portable/temporary subs, you can use them to test positions before you install the IB. (Be sure to try the four 1/4-1/4 positions.) Otherwise, download and use the "Room Response Calculator" or something similar. RRC only does 2 driver positions but, since you room is fairly symmetrical, you can input just one side...one lower position and one upper. Assuming your sweet spot is on the room centerline, the SW can do a reasonable job of predicting SS response with only 2 of the suggested 4 driver positions. Final positions for the portable 15s can be found empirically.

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post #12 of 27 Old 12-14-2012, 06:16 AM - Thread Starter
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Excavation has begun :

At the time of this post, backfill is complete and steel + Spancrete being set in place. Below are pics leading up to this :


Forms getting setup:



Future Home HT (under 3 car bay) from above :



Looking towards rear wall and entry to HT from outside :



Looing at rear wall of HT from outside:



Standing in HT at front right corner looking back at left rear corner:



Standing in HT at front left corner looking back at right rear corner and entry:



Standing in single car bay looking towards HT:



Standing at front right corner of home looking diagonally towards rear:



Standing at front left corner of home looking diagonally towards rear:



Standing in front of home looking at side-load bay (HT below it) :



Looking down at walk-up entry to basement:

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #13 of 27 Old 12-14-2012, 08:05 AM - Thread Starter
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I should mention the screen will be retractable (10 or 12' wide) since a 60" TV will reside on the wall when the screen is not needed. The screen case will be secured to the Spancrete ceiling (3bay garage floor). This wall will be extremely heavily braced and the knee wall/baffle will be decoupled to a certain degree from the wall as well. I'm not too worried about vibrations at this point.

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #14 of 27 Old 12-15-2012, 05:49 AM - Thread Starter
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I have designed the wall with the IB subs stacked vertically, 4 per side, but this would necessitate even more structural reinforcement. Having them all mounted horizontally at the bottom makes it easier to design in additional reinforcement. Plus it is no less visually jaw dropping seeing eight foot-&-a-half cones pointing at you. Having manifolds as others have suggested would hide the drivers. I want folks to know what their in for the second they enter the room. wink.gif

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #15 of 27 Old 12-16-2012, 11:18 AM
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Just wanted to say that I think you're room is going to turn out to be real neat! I totally love the concept of the 'under the garage' room and would have loved to do one in our current house, but did not find out about the possibility until about 6 months after it was built. The house would have lent itself perfectly to the idea as there is a 1200 sq.ft. (4-5 car) garage and we have a walkout basement with all windows a few feet above ground level -- a 700 sq. ft. bunker theater and a 500 sq.ft. gym/workout area connected to the main walkout basement by a hidden hallway would have been absolutely killer. I would still love to do it...maybe someday.

Looks like a pretty nice neighborhood you're in. smile.gif
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post #16 of 27 Old 12-16-2012, 11:48 AM
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Sweet build. Nice big room eek.gif

Be mindful, if you can .... that spreading the drivers in both the vertical and horizontal across the screenwall is a technically superior approach. Would it matter? Yes, but hard to say how much.

Best of luck

------------------------------------
Flat, Deep, Clean, Linear, and Loud
------------------------------------
Active 16.8kw, 7.3 system
(3)Seaton Cat12C up front, (4)QSC K8 sides/rears
(2)Seaton SubM-HP, (4)18" IB
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post #17 of 27 Old 12-17-2012, 05:21 AM - Thread Starter
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Quote:
Originally Posted by Aaron Smith View Post

Just wanted to say that I think you're room is going to turn out to be real neat! I totally love the concept of the 'under the garage' room and would have loved to do one in our current house, but did not find out about the possibility until about 6 months after it was built. The house would have lent itself perfectly to the idea as there is a 1200 sq.ft. (4-5 car) garage and we have a walkout basement with all windows a few feet above ground level -- a 700 sq. ft. bunker theater and a 500 sq.ft. gym/workout area connected to the main walkout basement by a hidden hallway would have been absolutely killer. I would still love to do it...maybe someday.
Looks like a pretty nice neighborhood you're in. smile.gif


I originally wanted to build a large ranch style home which in turn means a huge basement. After coercing me we went with the 2 story my wife wanted.

I wanted a space that was 100% UNOBSTRUCTED by HVAC duct work, beams or poles. Spancrete (and it's other trade names) allows this. Since no one lives in the garage (not yet anyway ;-) ), I don't have to go overboard with any isolation techniques (DD, GG, clips....); although, the manner in which I will be re-enforcing the walls due to the IB Sub arrangement will already contribute to some isolation. The only real downside beyond the additional cost is the fact that you must excavate ~ two feet deeper for that area since the Spancrete and the garage floor (the top of the Spancrete will still have 4" of concrete poured over it) occupy about that much.


I'm pretty sure despite having planned this room for the better part of a year, the design will probably change between now and May'ish......

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #18 of 27 Old 12-17-2012, 07:05 AM
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Don't underestimate how much force will be on that wall if you go with a line array with 8 drivers. Really make sure it is well braced, vertically and horizontally if necessary.

My build thread

My 8 x RE XXX 18" Subwoofers, IB build
Couldn't pour water out of a boot with instructions on the heel.

Do you know what Nemesis means?

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post #19 of 27 Old 12-17-2012, 07:18 AM - Thread Starter
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Originally Posted by JapanDave View Post

Don't underestimate how much force will be on that wall if you go with a line array with 8 drivers. Really make sure it is well braced, vertically and horizontally if necessary.

Thanks for the advice JD!

I posted this a few post up :



I may use 2x8 for the wall in place of the 2x6 pictured. The rear bracing may include wall (rear of framed wall) to wall (concrete wall) bracing in addition to the wall to floor brace as depicted. Also note that the knee wall which is the baffle is a separate structure from the main wall and it too is heavily braced. Due to it being short and stout and secured to the concrete floor via a wide base, it should be very rigid in and of itself, yes?

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #20 of 27 Old 12-17-2012, 07:50 AM
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Quote:
Originally Posted by rms8 View Post

I originally wanted to build a large ranch style home which in turn means a huge basement. After coercing me we went with the 2 story my wife wanted.
I wanted a space that was 100% UNOBSTRUCTED by HVAC duct work, beams or poles. Spancrete (and it's other trade names) allows this. Since no one lives in the garage (not yet anyway ;-) ), I don't have to go overboard with any isolation techniques (DD, GG, clips....); although, the manner in which I will be re-enforcing the walls due to the IB Sub arrangement will already contribute to some isolation. The only real downside beyond the additional cost is the fact that you must excavate ~ two feet deeper for that area since the Spancrete and the garage floor (the top of the Spancrete will still have 4" of concrete poured over it) occupy about that much.
I'm pretty sure despite having planned this room for the better part of a year, the design will probably change between now and May'ish......

I totally agree -- it does seem like a nearly ideal location for a HT room. The isolation provided is spectacular, and another huge benefit is the free geothermal room conditioning effect you will have from a room without windows and surrounded by earth on 4 sides with a thick concrete top as well.

The only downside I've heard about that you did not mention is that because the room is a total concrete-encased bunker, the room modes will be a little more prominent and stubborn to deal with due to the stiff nature of all of the surfaces. This seems like a fair tradeoff to potentially have to deal with to get this type of 'free' isolation IMHO.

Also, the tactile 'feel' for the listener from a room with a concrete floor is inherently lesser than a room with a wood-based substructure. Are you going with any type of wood subfloor or going to roll with the concrete?I believe this can be largely overcome with Vd from the drivers; especially after seeing JapanDave's report back from the initial test run of his 4 RE XXX 18" IB in his concrete bunker room. 51 liters of Vd goodness can provide it's own kind of tactile feel without the need for extra structure quivering apparently. So, of course, he's going to add another 3 XXX's to the mix soon to bring him up to 89 liters... smile.gif

rms8, you'll have a stout 58 liters with your 8 FI's -- maybe you want to buy my 4 NIB FI's (I just ordered 8 Stereo Integrity 18's) to bring you up to 12 so you can keep up with Dave? biggrin.gif (would put you at 87 liters)

One construction detail I am curious about -- I know they do a 4" pour over the Spancrete, but are there measures taken for waterproofing the ceiling of the HT room? Some sort of rubber membrane between the two or something?
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post #21 of 27 Old 12-17-2012, 07:52 AM
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Yes, that should be a pretty solid wall. But I would add a layer of 1" ply with the OSB and drywall. Also I can't remember where I saw it, but someone was still experiencing flex with 2 x 8 bracing around the line array. You may even what to consider doubling up the 2 x 8's just to be sure. It should not cost that much more to do it and I would rather have the piece of mind that I am getting the full potential from the drivers.

Nice looking build BTW, I bet you can't wait for it to be completed?

My build thread

My 8 x RE XXX 18" Subwoofers, IB build
Couldn't pour water out of a boot with instructions on the heel.

Do you know what Nemesis means?

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post #22 of 27 Old 12-17-2012, 11:02 AM - Thread Starter
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Quote:
Originally Posted by Aaron Smith View Post

I totally agree -- it does seem like a nearly ideal location for a HT room. The isolation provided is spectacular, and another huge benefit is the free geothermal room conditioning effect you will have from a room without windows and surrounded by earth on 4 sides with a thick concrete top as well.
The only downside I've heard about that you did not mention is that because the room is a total concrete-encased bunker, the room modes will be a little more prominent and stubborn to deal with due to the stiff nature of all of the surfaces. This seems like a fair tradeoff to potentially have to deal with to get this type of 'free' isolation IMHO.
Also, the tactile 'feel' for the listener from a room with a concrete floor is inherently lesser than a room with a wood-based substructure. Are you going with any type of wood subfloor or going to roll with the concrete?I believe this can be largely overcome with Vd from the drivers; especially after seeing JapanDave's report back from the initial test run of his 4 RE XXX 18" IB in his concrete bunker room. 51 liters of Vd goodness can provide it's own kind of tactile feel without the need for extra structure quivering apparently. So, of course, he's going to add another 3 XXX's to the mix soon to bring him up to 89 liters... smile.gif
rms8, you'll have a stout 58 liters with your 8 FI's -- maybe you want to buy my 4 NIB FI's (I just ordered 8 Stereo Integrity 18's) to bring you up to 12 so you can keep up with Dave? biggrin.gif (would put you at 87 liters)
One construction detail I am curious about -- I know they do a 4" pour over the Spancrete, but are there measures taken for waterproofing the ceiling of the HT room? Some sort of rubber membrane between the two or something?

For tactile feel, I have implemented the next best thing to a full D-Box setup. My current seating platforms are built in a "flimsy" nature. Two original Buttkickers (the bigger ones) shake the platform while Aura Bass Shakers (4 per couch) vibrate the actual seats.

My next theater will take my "flimsy" platform + ButtKickers one step further. I will mount 2 BK'ers per platform. There will be one in one corner with the second catty-corner from that, and wired out of phase to eachother. This will really get the inertia going and cause the whole platform to vibrate more than it currently does with a single corner mounted BK'er arrangement. This is a proven design as far as I am concerned as it has REALLY opened everyone's (those who have been in my current HT) eyes to the fact that there is single digit content on blue-rays. The BEST part about this whole BK'er + flimsy platform concept is that you're getting the ultimate tactile sensation WITHOUT any damage to your ears.

The trick is the isolation feet are not mounted in the traditional/logical locations. Instead of providing maximum support for the platform, they support the inner portion of the platform only. This allows the edges/ends of the platform to actually bend and dip a bit if you stand on it. Below is an old pic of my first experiment with this design (note location of feet on right side of pic). My future platform will be independent for each row, as opposed to the single platform for both rows below. Plus, since the concrete floor has zero give, all that motion from the BK'er through the platform is all sent into your body via the seats!! Words simply cannot describe the sensation other than to say its a poor-man's D-Box !


Regarding your question about waterproofing the top of the spancrete....Yes, they will have a membrane between the spancrete and concrete poured over it. This will prevent any sort of water/oil or whatever from leaking through.

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #23 of 27 Old 12-17-2012, 11:47 AM
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Originally Posted by rms8 View Post

For tactile feel, I have implemented the next best thing to a full D-Box setup. My current seating platforms are built in a "flimsy" nature. Two original Buttkickers (the bigger ones) shake the platform while Aura Bass Shakers (4 per couch) vibrate the actual seats.
My next theater will take my "flimsy" platform + ButtKickers one step further. I will mount 2 BK'ers per platform. There will be one in one corner with the second catty-corner from that, and wired out of phase to eachother. This will really get the inertia going and cause the whole platform to vibrate more than it currently does with a single corner mounted BK'er arrangement. This is a proven design as far as I am concerned as it has REALLY opened everyone's (those who have been in my current HT) eyes to the fact that there is single digit content on blue-rays. The BEST part about this whole BK'er + flimsy platform concept is that you're getting the ultimate tactile sensation WITHOUT any damage to your ears.
The trick is the isolation feet are not mounted in the traditional/logical locations. Instead of providing maximum support for the platform, they support the inner portion of the platform only. This allows the edges/ends of the platform to actually bend and dip a bit if you stand on it. Below is an old pic of my first experiment with this design (note location of feet on right side of pic). My future platform will be independent for each row, as opposed to the single platform for both rows below. Plus, since the concrete floor has zero give, all that motion from the BK'er through the platform is all sent into your body via the seats!! Words simply cannot describe the sensation other than to say its a poor-man's D-Box !
.

My 'tactile feel' concerns for your room--->CHECK! biggrin.gif I see the idea has crossed your mind. smile.gif Sounds like a pretty cool implementation.

I hope I get lucky for tactile feel in my room and won't have to go through all the work you did. Based on a few tests done with smaller subs, this room totally floating over the garage being driven by 8 18's should be like sitting on one giant Buttkicker. smile.gif
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post #24 of 27 Old 12-17-2012, 12:21 PM - Thread Starter
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Originally Posted by Aaron Smith View Post

, this room totally floating over the garage being driven by 8 18's should be like sitting on one giant Buttkicker. smile.gif

Is this your HT you mention? Or did you mean "under" ?

If this is yours, puhlezze privide a link to pics!

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #25 of 27 Old 12-17-2012, 02:14 PM - Thread Starter
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Yes, that should be a pretty solid wall. But I would add a layer of 1" ply with the OSB and drywall. Also I can't remember where I saw it, but someone was still experiencing flex with 2 x 8 bracing around the line array. You may even what to consider doubling up the 2 x 8's just to be sure. It should not cost that much more to do it and I would rather have the piece of mind that I am getting the full potential from the drivers.
Nice looking build BTW, I bet you can't wait for it to be completed?


I'll make a note of the 1" plywood and additional 2x8's ! Thanks!

Your build looks remarkable to say the least! Awesome!

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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post #26 of 27 Old 12-17-2012, 03:02 PM
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Originally Posted by rms8 View Post

Is this your HT you mention? Or did you mean "under" ?
If this is yours, puhlezze privide a link to pics!

It's a bonus room directly above the garage...kind of vaporware really. rolleyes.gif The room was built without HT on the radar many years ago and is a I-wish-it-were-bigger 12'x24'. It was going to be a HT/office combo (with the screen in a dormer on one of the long walls), then right at the point of mudding/taping I put the brakes on the project and decided to flip the orientation and dedicate it all to HT. Reasons for the delay: work and life in general became too busy for a few years after my business partner left--->then my wife and I started planning out a couple of different additions (for a larger HT room) that in the end just didn't make financial sense in this neighborhood--->then I was kind of turned off to the whole project as we started thinking about building again. But the realization is the room is a great location for a HT room, and even if we do end up building another house, it needs to be finished and I'm sure the buyer will enjoy the room quite a bit (even if it is a bit narrow).

The 'makeshift' HT room in the basement family room isn't a terrible place to be and has probably been one of the reasons for the delay: anchored by a pair of LS-6 line arrays, various capable subs that have come and gone, a 60" plasma viewed from 9' away, seating for 12 or more (big 12' sectional with as many barstools as we want behind it), and about $10k retail worth of ASC tube traps/wall panels that I picked up stupid cheap on CL.

Appreciate the fact that the guys here haven't banned me for all of the chatter without any action...hope to rectify that soon. biggrin.gif
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post #27 of 27 Old 12-18-2012, 12:32 AM
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Regarding the use of additional speakers for the purpose of "EQ".... i am a big fan of the "less is more" theory, not in the regards of displacement, but regarding number of types of drivers used in the system.... for example 1 driver capable of 20-20khz @ 140db all the way across would be great.... but until then we have to mix-and-match best we can... so i advise keep it simple when it comes to the speakers... you may want to get creative in the digital EQ department instead. i dunno, thoughts of phase and x-over issues and other gaps/peaks come to mind that may make it even more difficult to smooth out when using similar types of speakers (i.e. ultra LF subs) that need to cover different bands which are close to each other. dag that doesnt even make sense the way i just said it..... anyway i have always had better luck when properly using less speakers, with better attention to system design in order to achieve a better quality sound... hope it helps
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