3 Inch thick cement ceiling - installing speakers

I am putting MC80 speakers in the cement ceiling. Haven't purchased yet. Ceiling is 3in thick then it is hollow.
I realized the dog ears don't extend beyond an inch or so. I thought about replacing the screws which the dog ears are attached to and putting in say 3 1/2 inch screws.
Does anyone know if this would work? Oh, and did I mention I am doing this in Mexico? as such, I have to carry speakers down to Mex and don't have any room to be wrong.



  • txcoastal1txcoastal1 Posts: 7,433
    You would have to trim back the white plastic guide for the dog ear flange
    See attached pdf I made up
  • johnonjohnon Posts: 2

    Great response!!

    So I trim that back then the dog ears can extend beyond that limit (with my 3 1/2 inche screws) is what I understand. Any idea why they have that plastic limit there? Is it creating resistance so under normal conditions you can snug it back to the drywall? Any risk that I won't be able to "snug" the dog ears back without that plastic limit because they are kind of floating, if that makes sense.

    Thanks! and double thanks for taking the time to make a mock up!
  • mdaudioguymdaudioguy Posts: 3,896
    The design ensures the dog ears turn and stay in the proper position (outward) when you start tightening the screws (with a normal ceiling). It won't do that with longer screws. Any chance you could position some wood above the hole and screw directly into it? This job is going to call for some good improv skills.
  • txcoastal1txcoastal1 Posts: 7,433
    mdaudioguy is correct
    The plastic not only guides it but it allows you to drive the screw into the dog ear
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