Sub built in to TV stand?

Discussion in 'Home Theater Projects' started by Christpher_S, Apr 25, 2004.

  1. Christpher_S

    Christpher_S Stunt Coordinator

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    Hi Folks.

    I'm about to build a pretty large stand for my tv, which will house HT components and provide some storage space for CD's and DVD's. I'm going to end up with quite a bit of void space inside this thing on the bottom and I'm thinking this would be great to use as an enclosure for a sub. After playing around with the design some, I can get an easy four cubic feet and maybe up to five if I increase the construction complexity a fair amount.

    Could someone take the time to make a couple suggestions I should go research? I've been reading through quite a few posts here on the Tempest sub with a plate amp and that sounds like a very nice way to get performance at a good price. It looks like most folks are using enclosures with twice the volume I have to work with though. I'll try to give a pretty good list of constraints for the project below. Sorry if it makes this post really long. BTW, I'm using an old Energy S8 with B&W DM303's right now, so there is huge room for improvement.

    System will be used 80 percent for HT.

    Budget for driver(s) & amp(s) is $500.00 or less.

    The only surface large enough for a driver over 10" inches is the bottom but I could go up to 18" if down firing is the way to go.

    I need to keep the clearance between the cabinet and the floor as low as possible to keep the overall height of the cabinet where I want it. My TV is going on top...

    The downstairs of my house is basically just open space, wrapping around a column for the staircase and other stuff. Picture a 25' by 28' rectangle with a 10' by 6' retangle in the center and you're pretty close. The 10' by 6' retangle is the only divider between "rooms". The sub will sit against one wall of this center section.

    I own high quality wood working tools and I know how to use them, so that's not a problem. I don't have time to spend on things like TL even though I probably could build it and I do have an interest. The KISS principle is telling me to find a 12" or 15" driver recommended for use in 3.5 to 4 cube enclosures, tune my volume to exactly what the manufacturer suggests, and seal that sucker in there firing down at the floor. I know a ported or PR design could do a lot to fill my large room with sound though.

    So, have I given enough info to help narrow down my choices?

    One specific question I have is how close can I get my driver to my tube TV? Also,how much clearance do I need below my enclosure for a down firing configuration? Floor is wood.


    Thanks for any help!

    -Chris
     
  2. Joey Skinner

    Joey Skinner Second Unit

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    You might have a problem with the magnet of the sub driver affecting your TV unles it is a plasma or LCD.
     
  3. Mark Shannon

    Mark Shannon Screenwriter

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    I'm no expert, but a general rule of thumb is nowhere close.
     
  4. Bob Bartlett

    Bob Bartlett Stunt Coordinator

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    I agree. I couldn't get my tempest within a few feet of my crt and I had problems.
     
  5. DanielKellmii

    DanielKellmii Supporting Actor

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    The magnetic field of the magnet is probably too large to place it in a TV stand, although, that is a really great idea. With the skills, tools and budget you have, you should check out "The Cult of the Infinetly Baffled." Just do a search. I plan on doing on sometime in the next 6 months.
     
  6. Dave Poehlman

    Dave Poehlman Producer

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    I would agree with the other posts in saying you would need to go with a shielded driver... or, at the very least, attaching some bucking magnets.

    Also, the vibrations from the sub may wreak havok on your DVD/CD player causing them to skip.
     
  7. Christpher_S

    Christpher_S Stunt Coordinator

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    Joey/Mark/Bob,

    Thanks for the info. I'm pretty concerned about the magnetic field but I like this idea so much I think I'm going to order a driver and do a little testing, but with a cheap TV.

    Daniel,

    I've been reading about IB but my system is downstairs so there is no attic to use as the enclosure. I'm considering playing around with it in the master bedroom though. There are already speakers mounted in the sloping ceiling above the TV so it wouldn't bother me much to do another one up there. There are already speakers wires run up there so I might be able to make it happen pretty easy.

    Dave,

    I was concerned about the vibration as well. I found a thread about using large sub enclosures as end tables though and most people stated that the vibration of the cabinet wasn't bad. I have a feeling the weight of the cabinet and having a 36" tv, plus HT components sitting on top, will keep it reasonably still. Maybe. [​IMG]

    -Chris
     
  8. Christpher_S

    Christpher_S Stunt Coordinator

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    If anyone is interested, I spent some time on the Adire web site and then tweaked my cabinet design a little. It looks like I can get enough volume to run a single Shiva in the EBS setup. I basically dropped my cabinet flat on the floor to keep the overall height where I need it but get more internal volume. Even after subtracting volume for the driver, bracing, and a port, I'm right at 5 cubic feet.

    If I mount the driver as far to one side as possible, I can get about 20" of separation between the magnet and my TV. I would actually like to do the PR setup, but I don't have a 15" flat surface to mount the radiator. The measurements they posted showed a flatter curve up toward the crossover point, which I think would be good since my main speakers are small. I know I could use two 10" radiators or something like that but then I wouldn't be able to take advantage of the work done by the manufacturer. I'll just go ported.

    Hopefully, I can find a way to shield the driver or something so this whole thing will work.

    Anyone see flaws in my logic before I jump in to this?

    -Chris
     
  9. GrahamT

    GrahamT Supporting Actor

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    I have my downfiring EBS Tempest right beside my 32" CRT. There is no problem. But When I used to have it in a front firing enclosure I couldn't even get the driver within about 2.5'.

    Another thing to consider is that the best place for the TV may be a poor place for the sub. You wont really know until you build it thought. Good luck with the project
     
  10. Christpher_S

    Christpher_S Stunt Coordinator

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    Graham,

    I know the room positioning for the sub isn't the best. There just isn't a clean way to run cables anywhere else though. I would have to run a cable up two floors to the attic and then fish it back down on the other wall. My little Energy S8 doesn't do as bad as you might expect and it's pretty close to the location where the new sub will be. I've been reading about the BFE and it sounds like it might be a good addition to my system. Even if I don't get optimum performance, I expect it will be far superior to what I have now.

    -Chris
     
  11. Dean-P

    Dean-P Stunt Coordinator

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    My 54l shiva sits right beside my tv and during action scenes, will actually shake the screen.[​IMG]
    I think putting a sub under the tv for a stand would/could cause the tv to over vibrate...
     
  12. Christpher_S

    Christpher_S Stunt Coordinator

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    You guys are so negative. [​IMG] It looks like I need to find a way to do some testing before jumping too deep into this. I could probably build a sealed enclosure for a Shiva in a few hours so maybe I'll do that and place it next to the tv to see what happens. I might be able to sell it or something after...

    Thanks for all the advice. I appreciate it, even if you guys are taking my dreams and stomping on them. [​IMG]

    -Chris
     
  13. DanielKellmii

    DanielKellmii Supporting Actor

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    A few hours!!!! Man, you are good.
     
  14. Joey Skinner

    Joey Skinner Second Unit

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    If you have the driver (or something similar) just place it by your TV and move it closer until you get distortion then you'll know how close you can put it. You can also shield it with thick 1/4 in steel plate. Maybe someone else will know more on how to do that.

    I had problems with with my old Pioneer HPM 100s; I couldn't get them within 3 to 4 feet of my Sony CRT tv. Then I built my GR Reseach AV3 HT system and I couldn't get the shielded center speaker within a couple of feet. Always had a green spot in the corner of the tube which went away when I moved the TV to the bedroom. Now I have a Sony lcd rear projection that is not affected by magnetic field.

    Sorry about the negativity but magnetic fields from huge speakers and CRTs don't mix!

    Let us know how it goes. There is probably a solution out there.
     
  15. Christpher_S

    Christpher_S Stunt Coordinator

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    Daniel,

    I'm not talking about a nicely finished box in a few hours. But, cutting the panels on the tablesaw, using the jigsaw to make some holes in the internal bracing then slapping some glue on and clamping it all together could be done in an afternoon I think. A biscuit joiner would speed it up even more. If you haven't used a biscuit joiner before, it's amazing how fast you can put together MDF and have it come out nice and square.

    Joey,

    I was just joking about the negativity thing, as I'm sure you realize. Apparently there is a dealer in Colleyville that stocks the Adire drivers so I think I'll pick one up. I'm in South Denton County by the way. (Just noticed your location)

    -Chris
     
  16. Dennis_H

    Dennis_H Stunt Coordinator

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    Who is the dealer in Colleyville? I'm in Bedford and would love to see what their prices are.

    Dennis H
     
  17. Christpher_S

    Christpher_S Stunt Coordinator

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    Dennis,

    This is from the Adire Dealer Search page. I haven't called yet so I don't have any other info about them.

    -Chris


    Colleyville Loudspeaker Works
    309 Glade Road
    Colleyville, TX 76034
    PHONE: 1 817 577 0078
     
  18. Dave Poehlman

    Dave Poehlman Producer

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    That's the best way to find out for sure... just do it. I think it depends on how sensitive the TV is too. I was able to put some non-shielded 6.5" 2-ways right next to my 27" RCA crt with no problems.

    Of course.. you're talking about a 12" driver here.... good luck and keep us posted.
     

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