How open should an open back be?

Discussion in 'Shock Brother's DIY Amps' started by Polderpatat, Jan 23, 2019.

  1. Polderpatat

    Polderpatat TDPRI Member

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    I'm planning on making a tweed champ clone. But make a simple cube open back cab for it (so much deeper than a regular tweed champ). Why? just because I like the look of a cube amp haha

    However when searching for open backs, almost all of them seem like close backs with a hole in it, why do we want a semi backpanel?
     
    Last edited: Jan 23, 2019
  2. jsnwhite619

    jsnwhite619 Friend of Leo's

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    No back equals no bass response, probably no matter how deep you make it.

    Sent from my XT1585 using Tapatalk
     
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  3. luckett

    luckett Banned

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    So your footswitch and guitar cable don't fall out when you carry the amp.

    It would increase bass response if you made it long enough, but it would look like a really long square tube.
     
  4. FenderLover

    FenderLover Friend of Leo's

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    A back panel has a more finished look IMO. Any opening the size of the speaker is basically an open back, again IMO. I have gravitated towards a large oval just because it looks cool.
     
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  5. teletimetx

    teletimetx Doctor of Teleocity

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    Here's how I did the back of a 2X10 cab. Sounds good to me. As you can see, I used the top part for the input jack.

    fun experiment: make a back panel; then try your cab with and without the panel. Whatever panel you design should not be very expensive. Use your ears to decide.

    cab reverse 2.jpg
     
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  6. tubeswell

    tubeswell Friend of Leo's

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    With open-backed cabs, I reckon it’s a combination of personal preference about the convenience of having some place to stow your spare pedals and cables onboard your cab, and the aural ‘zing’ from the lack of back-pressure on the cone. I find that having somewhere between 1/3 to 3/4 of the cab back (by area) ‘open’ does it for me. This is based on my own ‘scientific experimentation’ ;-)

    (Edit: the speaker(s) and the type of amp, plays a part in the way it turns out too)
     
    Last edited: Jan 23, 2019
  7. schmee

    schmee Poster Extraordinaire

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    OK, warning: A deep cab will make it woofy and hi fi. It elevates bass response. That's why bass amps are deep and guitar amps are not.
    Other than that 1/3 open in the back is nice. Any openness over sealed is a significant change in tone. If you insist on a cube I wouldn't put a back on it at all.
     
  8. Urshurak776

    Urshurak776 Tele-Holic

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    I say whatever makes the woman comfortable. No complaints from me.
     
  9. Jimmy Dean

    Jimmy Dean Tele-Afflicted

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    I built a cab for a single 12 about 7 years ago. I used 2 panels in the back with a panel sized open space in the middle. After about a week I was not liking my tone. Cut another board & sealed up the hole just for kicks. I liked the sealed cab better, tighter & more focused. I also have the speaker front mounted. I do miss not having the cable or whatever storage area.
     
  10. jvin248

    jvin248 Poster Extraordinaire

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  11. magicfingers99

    magicfingers99 Friend of Leo's

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    butt-crack shouldn't show unless you're a plumber or paris hilton...
     
  12. RodeoTex

    RodeoTex Poster Extraordinaire

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    I asked a similar question a couple years ago and was told that the total number of square inches of open area on the back panel should at least be equal to the area of the speaker(s).
    I don't know the science but it has worked very well for me on three cabinet builds.
     
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