cutting into a closed speaker cab

Discussion in 'Amps and Cabs' started by andrewgreen, Dec 20, 2009.

  1. andrewgreen

    andrewgreen Member

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    i've got a 1x12 lopo line closed classic cab. i have discovered that i need an open speaker cab, but i do not want to ruin the purpose of the cab i have. plus, i cannot afford to buy another (more transactions = loss of money).

    any recommendations on how i should cut a 12x12 (or another size) port in the rear of the cab and possibly making it convertible (allowing the piece to be reattached)?

    thanks for the help.
     
  2. cap'n'crunch

    cap'n'crunch Member

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    I'm not real familiar with those cabs. If the back is removable then I'd just replace the back with painted pieces of birch plywood with the proper size opening that you need. If you want you could get some vinyl at Joanns fabrics to cover the pieces with. Who sees the back anyway? No need to buy a whole sheet of plywood. Lowes and Home Depot both sell smaller project sizes pieces of birch plywood. You could then get a third piece of plywood to screw into place covering the opening to make it convertible. Just attach some wood strips to the inside back opening to screw the convertible piece to.
     
  3. Sean

    Sean Supporting Member

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    I have a 1x15 Lopoline cab from before they were called Lopoline. The speaker was front loaded into a closed back cab. I wanted an open back, so I found some 6 inch speaker ports on Ebay, cut a hole in the rear of the cab and glued the port in so it looked nice. It worked great. I also did it with a closed back 2x12 and had similiar good results.

    The downside is that it is not reversable- both cabs did not have screwed on backs.

    I will post a picture later if I get a minute.
     
  4. blackba

    blackba Supporting Member

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    I converted a couple of my cabs to opened back. I just make a new back. I ordered the 3/4" 13ply plywood, cut 2 strips and left about a 4-5" opening. I added the jack in one section. I then covered the new back pieces with tolex. Turned out great.

    http://www.woodnshop.com/Hardwood/Baltic_Birch_Plywood.htm

    Update: Found picture of the back. This cab was a closed back Fender Bandmaster 212 cab. The nice thing is I still have the original back if I want to go to closed back.

    [​IMG]
     
    Last edited: Dec 20, 2009
  5. andrewgreen

    andrewgreen Member

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    cap'n'crunch: i wish the back was removable, but lopoline makes there closed cabs with a non-removable back, which is an essential part of the cab structure. thanks for the advice, though!

    sean: how do you like those ports? would a port sound different than a larger rectangular cut out?

    blackba: thanks, man! appreciate the advice.
     
  6. andrewgreen

    andrewgreen Member

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  7. Sean

    Sean Supporting Member

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    I have no idea what the difference would be with different shapes- I assume there would be a difference. All I know is I turned a cabinet that didn't work well for me into one that did.

    I also had to cut the port that I bought- it was a port "tube". I know that different length tubes affect different frequencies, so I cut the port flush with the back of the cab. I basically cut a hole in the back of the cabinet and used the port to make it look nice. I couldn't think of a better way to do that (maybe weather striping of some sort would work?).

    Also keep in mind that the back of the cabinet is sort of load bearing in cabinets like that- if you cut too much away, I'm guessing structure of the cabinet may be a bit compromised.

    I will put a picture up as soon as I get done putting up the Xmas tree.
     
  8. Dave

    Dave Member

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    The size of the opening is more critical than the shape. Hard to say what would be best for your particular cabinet, but I would start with a hole that is the same area as the speaker. For a 12" speaker (actually about 11.5") the area is about 95 inches, so try a rectangular hole about 8" x 12", or whatever dimension works out to about 95 inches.
     
  9. Sean

    Sean Supporting Member

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    All right- these pictures are going to make some people cringe, but that's OK- this works for me. I realized that I do not like closed back cabinets, so I opened them up the best way I could figure out.

    Lopoline 1x15
    [​IMG]

    [​IMG]

    Fender 2x12- I started with 2 ports, and there wasn't much change, so I added 2 more and got the open back sound I was after.
    [​IMG]
     

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