Accoustics affected by 12" beam?

Discussion in 'Archived Threads 2001-2004' started by Aaron Gould, Mar 4, 2002.

  1. Aaron Gould

    Aaron Gould Stunt Coordinator

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    Hi all,
    I would like to knock out a wall in our 11'-7" x 11'-3" basement room to make it 11'-7" x 18'-0". The wall I will be knocking out is a load-bearing wall. Because of this, I need to install a support beam across the newly opened gap.
    Here's an illustration of the future room:
    [​IMG]
    The dark gray vertical line down the middle of the room (just off centre) is the current wall, where the header will be.
    My city's regulations require that I use 5 (five!!) 2x12's for the beam. So that means a drop of 12 inches from the ceiling. The ceiling is only 7'-7" high. So there will be a beam a full foot below the rest of the ceiling running through the middle of the room.
    My question is: will a one foot drop noticably affect the accoustics of the room -- in particular, will it affect the Front 1 and Front 2 speakers with respect to those sitting on the couch? A subwoofer will likely be placed on the front corner too -- will that be affected too my this beam?
    The front speakers are floor standing Mirage OM-10's while the rears are matching OM-R2's mounted on the wall approximately one meter above ear level. The center channel is an OM-C2.
    (The aforementioned sub is a Paradigm 10" sub that I currently own, but is not in the illustration as I have not figured out where that will be placed yet.)
    Thanks for any help or input you folks may provide!
     
  2. Joe Meissner

    Joe Meissner Stunt Coordinator

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    Check into the code more and see if it allows you to use a steel beem instead. you might be able to lose a few inches off that beem. i think a 6 inch steel beem is equel to a 12 inch wood beem.
     
  3. Dennis Erskine

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    The beam will have less an impact on sound in your room than the big flat reflective surface of the desk and lack of a center channel. Your OM's are not very directional...so the beam may actually help.
     
  4. Aaron Gould

    Aaron Gould Stunt Coordinator

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    Hey guys, thanks for the replies.

    Joe:

    I called my city's building division. Apparently steal is allowed. From what I understand, they haven't had a lot of queries on this topic. They said I'd need a contractor with experience in that area, or an engineer to let me know just what kind of mass is sitting above that load-bearing wall. That way, we can find out what kind of beam is actually required. If that's the case, and even several 2x10 wood boards would suffice, I could live with that. Obviously, less is better, but there's only so much I can afford to do!

    Dennis:

    I do have a centre channel speaker (Mirage OM-C2). I forgot to include that in the picture. It will likely be mounted on an arm fastened to the wall immediately behind the television, in the Entertainment Centre part of my illustration (my current TV's top is not flat, so the speaker can't sit on top of it). It will be aimed directly at the middle of the couch.
     
  5. Scott Jelsma

    Scott Jelsma Auditioning

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    I have a similar issue with my Home Theater. I am about 70% completed with the construction, but I also have an I-beam running across the room. I've wondered what the acoustical affects will be.
    I would strongly suggest that you get an engineer involved in calculating the load requirements if you remove the supporting wall. If you can go with steel, it should be narrower than wood.
    I put in a new I-beam in my basement so I could get rid of a support column that was right in the wrong spot. See the site below for pictures of the beam installation. The new I-beam is 10" tall and 19 1/2 feet long.
    http://home.attbi.com/~jelsma
     
  6. Aaron Gould

    Aaron Gould Stunt Coordinator

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    Well, I've decided to just go with the 2x12 boards.
    The reason being that I am in a condominium unit (townhouse type), and I don't plan on living there for more than a couple years. Because of that, I'm not willing to put a lot of money into the place. My budget for the entire renovation is standing between $1000-1200 (Canadian). That includes the drywall, carpet, paint, wiring, etc (already have the A/V equipment). There's only grey wood paneling, and old linoleum down there now, so it'll be a step up regardless. [​IMG]
    As Dennis has mentioned, my omnipolar speakers should not be noticable affected by the beam, so that pretty much convinced me to forget the steel. It'd be nice from a size perspective, but there's only so much money I can throw at this project.
    When I buy a house in the future, I'll know what to look for in a basement now!
    Thanks for the help guys!
     

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