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Building a Cabinet

Discussion in 'Amps and Cabs [BG]' started by bodhan, Aug 6, 2004.


  1. bodhan

    bodhan

    Nov 19, 2002
    Brazil
    Hi! I would like to build my own bass cabinet, probably similar to a GK 15". I have a Eminence LEGEND B15 speaker. This cabinet will be used in conjuction with my GK MB150E mini combo with a built in 12" speaker. Sorry to ask this on this forum ... I tried the search, but found nothing about cabinet construction projects. So, if anyone have any sugestion about this, I'll say thank you !!!!! :)
     
  2. Passinwind

    Passinwind I Know Nothing Supporting Member

  3. bodhan

    bodhan

    Nov 19, 2002
    Brazil
    Thanks! Big topic!
    Is there any free project for a bassguitar cabinet?
     
  4. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Is there a reason why you went for that speaker? I only ask because that speaker needs a fairly big cabinet. Roughly 200 to 300 litres ( 7-11 cubic feet), depending on your chosen allignment and tuning. Is the large size going to be a problem for you?
     
  5. The Legend CB15 runs in half the size. It is a bit more down at 43 Hz, but that is a result of the smaller cab size and fairly high efficiency at 97 SPL.
     
  6. bodhan

    bodhan

    Nov 19, 2002
    Brazil
    Ok, I confess: I have no idea about this matter. I thought you can just copy a cabinet dimensons and put any "good" bass speaker, and its done! Well, after a 2 day researching, I found a new world. Actually a big world.
    Petebass, I just found this speaker (the Legend B15) in a local store ... and after testing their specs into WinISD software, I realized what you meant: doghouse, a 308 L cabinet. Also, thanks to Bgavin: the CB15 can be mounted in a 100 L cabinet, and I'll send the B15 back to the store.
    I'll try to find a technician here to help me. Thanks, Guys!
     
  7. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    It's s great world though :)

    Do yourself a favour. Go and buy "The Loudspeaker Design cookbook" by Vance Dickason. It's the loudpeaker design bible. Even if you only ever build one loudspeaker in your whole life, it's worth the read. It also arms you with all the knowlege you'll ever need to help you chose which speakers to buy (wether for Bass, Pa, or even home Hi-Fi), and how to fix things when problems arise.
     
  8. bodhan

    bodhan

    Nov 19, 2002
    Brazil
    Thanks, Pete, I'll buy the book, but it takes 1 to 2 months to be delivered, and it'll take more 2 to 3 months to arrive in Brazil. I try another supllier other than Amazon...
    Meanwhile, I have another question: I tried the Eminence CB15 into the WINISD software and found a 4 cubic ft cabinet (113.26 litre), but according to Eminence's website: "Use one driver in a 2 cu. ft. box or two in a 4 cu. ft. box". Well, 2 cubic ft is 56.63 litres, is it ok to build such a small cabinet? It'll work ok with my GK MB150 with a 12 built in speaker ? Or, should I follow the WINISD and build a 100 litre cabinet?
    Remmember: I play jazz and bossa nova with my 4 string JazzBass.
    Thanks !
    ps.: I know that is much more logical to just go to a store and test / buy a cabinet, but that it's not true in Brazil, where prices for imported stuff are very, very high. Also the local industry can't match the quality of the big manufactures. That's why I am trying to figured out how to build a cabinet. Thank you all !
     
  9. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I'm not sure how Eminence came up with 56 litres? The is definitely too small for this driver, based on traditional speaker designs formulas and TS parameters.

    Stuffing a box into a small cabinet is nothing new. Lots of commercial cabs are made this way to give them a hump in the frequency response in the low mids, typically 100Hz or thereabouts. Bgavin refers to these cabs as those that "Honk". The trade off is it starts to run out of puff in the bottom end sooner, and the roll-off slope is greater. I wouldn't do it, especially since you seem to be playing smooth music that requires a smooth bass sound.

    If you need a smaller cab, there is a way to cheat a little bit. Stuffing the cabinet with acoustic foam tricks the speaker into seeing a larger cab. You can get up to 30% increase in cab volume if you stuff the cab completely. So you could build a 77 litre cab and stuff it (77*1.3=100), being careful of course not to obstruct the speaker movement or the air flow through the port. 77 litres isn't too big.