Bass Cab DIY

Discussion in 'Amps and Cabs [BG]' started by obird66, Feb 21, 2010.

  1. obird66


    Feb 21, 2010
    Im thinking of building a 2x12 bass cab, however this will be my first time and i hope that some of the answers to my questions will help out others like me.
    First i need a pair of speakers which can both handle 250W my thoughts was a pair of Fane SOVEREIGN 12-300, it states the vas litres is 62, is this number the disired volume of air behind the speaker and if i had a pair of speakers do i just double the number or is there a rule for several speakers. Also is the space behind the speaker 62 or (62- speaker's volume).

    I was considering of putting a port in the cab but firstly im not sure if it makes much difference, i have been told to be ports which are about half the diametre of the speaker, and also when it comes to it's position where is the best place to put them i was thinking below the pair smack bang in the middle.

    Lastly putting two speakers horizontally next to each causes constructive and destructive interference, if i was to put the speakers on one baffle board where there both facing the same direction will the interference effect be noticable.

    I'll be grateful for any answers
  2. Sundogue


    Apr 26, 2001
    Wausau, WI
    Do a search here on "DIY" and also "fEarful" and read those threads. There is A LOT you need to learn to build a bass cab that functions much less one that does it well.

    I'm not trying to dissuade you from doing the DIY thing because I think every bass player should try it at least once. But I can tell from your post you need to do some reading up on bass cab design before you launch into this. I just don't want your first DIY cab build to be your last because you didn't do your homework first.

    Ports are a function of "tuning" the cab correctly for a given output, so unless it is a sealed cab, ports (number, size, length) make a HUGE difference. The size of the speaker has nothing to do with the size of the ports. The correct design is everything.
  3. obird66


    Feb 21, 2010
    cheers for the advise i will check those threads out
  4. Sundogue


    Apr 26, 2001
    Wausau, WI
    Go here and download WinISD (both Beta and Pro). Learn to use it.

    It allows you to input the Theile/Small parameters of any speaker you might want to use and then it will give you an optimal speaker cab design (flat response...think like studio quality).

    Then you can design your box (bigger or smaller, change dimensions, etc.) and port tuning (tune it to 40 Hz or 50Hz, etc.) and you can then play around with your design and look at what affect is has on your output at different frequencies. Like if you want it to put out deep lows (bigger box), or be stronger in the mids (smaller box), for example. But you have to learn what those graphs mean in real world use.

    Keep in mind when building a bass cab, you can only have two of these three...Low, Loud or Small. You can't have all three in one cab.

    Then read up, and read some more. And then play around with WinISD some more. Then read some more. You'll want to spend more time designing your cab and even more time reading up on bass cab design, long before you actually build one. But it will be well worth it if you take the time to understand how your design affects what you hear.

    The most important thing to remember is that you have to design your cab and it's port tuning around the T/S specs of the speaker you choose. You have to match your cab to the speaker. It's the cab design itself that maximizes the speaker's capabilities.

    It's a whole lot more involved than simply throwing some speakers in a box. But it is a lot of fun if you like doing this kind of thing. For your first build you may want to use an existing, proven design to get the hang of it (the fEarful is one that comes to mind, or one of Bill Fitzmaurice cab designs).

    Many will tell you not to waste your time, but time spent learning anything is time well spent. And keep in mind that more is learned through failure than through success.
  5. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA