Help! Screw hole spacing for mounting speakers

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Meeotch, Sep 10, 2019.

  1. Meeotch

    Meeotch Supporting Member

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    I recently purchased a cab direct from a manufacturer, and I am struggling to mount speakers into it properly. The issue is that the screw holes that were drilled into the baffle for mounting are too far apart.

    Measuring from center of screw hole to center of screw hole directly across the cutout, I am getting 11 13/16". I have measured 7 different speaker frames and they all measure 11 10/16" to 11 11/16" hole to hole. This is 1/8"+ discrepancy, and I will surely strip the screws and/or tnuts if I try to force the screw in at an angle.

    I have measured 3 different cabs and they all are at 11 10/16" hole to hole, no angling of the screw necessary. I feel like the template this manufacturer used is off, but they are insisting that there is no problem with the 11 13/16" spec. I'm just trying to figure out what the standard is here, please help!
     
  2. Rod

    Rod Tone is Paramount Supporting Member

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    Contact the manufacturer.... their spacing is wrong...
     
  3. Red House

    Red House Silver Supporting Member

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    Just as an FYI, I bought a pair of EV SRO Coffee Cans, but I could not mount them to any of my existing baffles, and had to have new baffles made especially for them.
     
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  4. bob-i

    bob-i Member

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    That’s strange, I had a pair of them in the 70s and used them in several different amps including a twin reverb. They fit in everything.
     
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  5. Meeotch

    Meeotch Supporting Member

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    Thanks for the input, as I mentioned the manufacturer insists that their spacing is correct. I would appreciate any info on standard specs for the mounting holes.

    To me it seems like 11 10/16" is the sweet spot as it is within 1/16" of all the frames I have measured.
     
  6. tarweed

    tarweed Member

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    can you use a rat-tail file to go in 1/16 (diagonally) on each hole - without causing damage?
    Would that void warranty?
     
  7. Kyle B

    Kyle B Supporting Member

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    Mounting slot distance on Celestions is 11.7" ( example https://celestion.com/product/26/heritage_series_g1265/)

    Celestions are probably about as "standard" as you're gonna find

    10/16=0.625
    11/16=0.6875
    12/16=0.7500
    13/16=0.8125


    0.8125 - 0.7=0.1125

    That's over 1/10th inch - Quite a difference. 11 11/16 is closest to the Celestion figure

    You might ask them whose speakers are standardized on 11 13/16

    Then decide if it's worth fighting over. You'll pay return shipping at a minimum I'd guess.

    You could enlarge the holes on your speaker or the cab, or perhaps use thinner screws (but something high-grade so they don't snap)
     
    Last edited: Sep 11, 2019
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  8. Washburnmemphis

    Washburnmemphis Member

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    Is the manufacture saying that the 11 13/16" is correct or that their template is normally correct? Could be that someone on their end screwed up the spacing somehow. Maybe try and send them some pics with a ruler showing what the actual measurements are.
     
  9. Pete Cage

    Pete Cage Member

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    11-5/8" is the measurement that I find best matches up with the range of most current speaker manufacturers' interpretation of a proper bolt circle on a 12" speaker. It seems that every builder has their own design-center spec... :mad:
     
  10. BluntForceTrauma

    BluntForceTrauma Member

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    Spin the speaker and drill new holes between the holes you have now.
     
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  11. wall_of_sleep

    wall_of_sleep Member

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    Nah mate, there's a 16th of an inch here somewhere and we're going to rip every board out of this house to find it.
     
  12. Meeotch

    Meeotch Supporting Member

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    Thanks for all the replies, my plan is to do just that...spin the speaker and drill new holes. It sucks to have to do that to a brand new cabinet, but at this point it's the only way to guarantee the holes are where I need them to be!
     
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  13. mattthehoople

    mattthehoople Member

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    Its a pain in the ass because the grill cloth is already installed. I'd return the cab if possible and just try to get a refund.

    If not, are you going to try drilling from the back of the baffle or are you taking off the grill cloth? I've never had an issue with Marshall, Mesa, Custom Audio, or Mojotone. But I have had a bad cab from another maker. It wasn't even remotely close to Celestion or Eminence clones. My Mojotone and CAE were balls on, drop dead center.
     
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  14. Meeotch

    Meeotch Supporting Member

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    Luckily the entire front grill is removable, so it will just be a matter of drilling and hammering in some t-nuts. I'm withholding the manufacturer's name for now because I'm not looking to throw anyone under the bus, but they have been great to communicate with and have assured me they will replace the cab if I mess it up.
     
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  15. mattthehoople

    mattthehoople Member

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    Because I'm kind of weird about cabinets, I would use small wooden dowels and plug the holes using wood glue, then razor off excess and sand smooth. You don't want to get all wired up and reassembled only to find out you have a strange whistling coming out of the four holes that are "coloring" your mic signal. I've had ported cabs produce some unwanted phase issues. I prefer sealed cabinets, like tightly sealed. Horses for courses.
     
  16. Meeotch

    Meeotch Supporting Member

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    That's a good point, thanks for chiming in. I'm hoping that the installed speaker's gasket will seal the holes that are not in use. But if I notice anything weird, your approach sounds perfect.
     
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