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fEarful™ 12/6 & 15/6 enclosure designs - FREE! (Part II)

Discussion in 'Amps and Cabs [BG]' started by Kelly Lee, Apr 3, 2009.


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  1. Swift713

    Swift713

    Dec 4, 2006
    Florence, Ma
    Yeah, I don't have a dado set for my table saw. Plus, some of the dado's aren't thru cuts. I never invested in the undersized plywood router bits either. I have total faith in Titebond.
    I'm 1/2 way through the glue up and I'm happy to say I'm a better bass player than cabinet builder ;) but I can always make a prettier box if I care.
    So where are people putting their crossovers? What sort of gauge wire should I be using? The 3012lf has nice screw down wire clamps but should I solder wire to the alpha, crossover, and jack?
     
  2. vlad335

    vlad335 Supporting Member

    Apr 14, 2003
    Latrobe, PA
    Always solder connectors. ( Except 3015LF and 3012LF) If you use spade connectors they are going to slip off eventually, and this will invariably happen at a gig. :D
     
  3. vlad335

    vlad335 Supporting Member

    Apr 14, 2003
    Latrobe, PA
    I plan to biamp so can't answer the crossover question. Mr. Fitzmaurice recommends 16ga wire for wiring inside a cab. Personally I like to use 16 gauge copper automotive hookup wire I buy at Walmart in black and red colors. It's cheap and easy to solder to Speakon connectors. According to Bill, you don't need expensive heavy gauge speaker wire for the short run inside a cabinet.
     
  4. GregBlach

    GregBlach

    Mar 5, 2009
    Denmark
    Hi all,

    As some of you may have noticed I am building a 12/6 (3012LF + 6ND410) and a 12/- (3012LF). I intend to use passive crossovers. I was looking at the Eminence crossovers, but it seems impossible to buy them here in Europe.

    So, I was searching for alternatives and came across these two:

    Link Dynamics X/over 2 way 800 Hz

    Link Dynamics Lo-pass filter 800Hz

    Don't they look like they will get the job done? :confused:

    /Greg
     
  5. davio

    davio

    Nov 2, 2006
    Boston, MA
    Or paint it clear! I definitely vote clear.
     
  6. Looking at the response chart for your 6", it appears to me than no less than 1,000 Hz is the optimal crossover point.
    The cost of passive components isn't prohibitive at this frequency.

    If you build a passive crossover, both 12" cabs must be used at all times, or the crossover will not work properly.
    An active crossover with bi-amping will cure this problem and allow you balance the levels or use only one cab.

    If you go passive, a Linkwitz-Reilly 4th order will protect your 6" from getting pounded. It will not protect against over voltage.
    Pink noise typically models music signal where the power density rolls off at the rate of -10dB per decade.
    This means 1000 Hz power is down -10dB from 100 Hz power.

    50% input power for the 6" driver (60w) is a conservative safe point below power compression.
    Raise this 60w by +10dB to get 600w for the woofers.
    This is 300w per 3012LF driver, or 66% of rated input power. If you have a limiter set to 49v (300w into 8 ohms) you should be good to go.

    Note this 300w is music program, not swept sine.
    A swept sine at this level will smoke your 6" driver.
     
  7. GregBlach

    GregBlach

    Mar 5, 2009
    Denmark
    bgavin,

    Thank you for your reply, although most of it is way beyond my knowledge. :meh:

    You did notice the crossover and lo-pass filter I refered to in my previous post, right? I was looking for something like this dividing at 800Hz because it had been mentioned by greenboy several times in this thread, that this would fit the 12/6 very well.

    I really don't know anything about crossovers what-so-ever, but you say an active solution might be a way to go? Would you please educate me by making an active crossover suggestion for my setup?:

    12/6
    12/-
    Eden WTX-260

    /Greg
     
  8. davio

    davio

    Nov 2, 2006
    Boston, MA
    Greg, greenboy and others have posted numerous times about their DSP solutions. Do a quick search and if you can't find anything maybe someone will chime in with some help.
     
  9. MX21

    MX21 Supporting Member

    Sep 28, 2007
    Grass Valley, CA
    I put mine on the ceiling, just above the jack plate. I glued 4 small blocks of leftover plywood scraps where the corners of the crossover would be. Then screwed the crossover to the blocks.

    MX
     
  10. MX21

    MX21 Supporting Member

    Sep 28, 2007
    Grass Valley, CA
    Exactly what I used, except mine's green and red, since it's what I had on hand.

    I temporarily used spade terminals since I'll have to pull everything out when I put on the finish.

    MX
     
  11. rdpbass

    rdpbass Supporting Member

    Oct 29, 2005
    Utah
    OK I wanna build the 1212/6 I think it would be a nice stand alone. But I'm not able to figure out the parts I would need for a cross-over. I can figure out schematics.It's just figureing the values that have me messed up. does any one know of a cross-over schematic thatwill work with the 4 ohm 12's and 8ohm 6, or if some one can do the math I'd could build it. I think GB did a great job on the plans. I've gotta gutard I need to bury.
     
  12. Why bother with doing the math the hard way?
    There are any number of L-R 4th order calculators on the web.

    All you have to know is the actual impedance of each driver at the crossover frequency. The nominal value is not sufficient.

    You plug in these impedance values into the calculator, and it gives you the values for the inductors and caps. It even gives you a picture.

    You will find the cost of the passive components is probably the same (or higher) than a decent, used active crossover.
     
  13. synaesthesia

    synaesthesia

    Apr 13, 2004
    UK
    +1. Also it gives you options in driver choice as you can match levels electronically.
     
  14. GregBlach

    GregBlach

    Mar 5, 2009
    Denmark
  15. GregBlach

    GregBlach

    Mar 5, 2009
    Denmark
    Which crossover did you end up getting?
     
  16. MX21

    MX21 Supporting Member

    Sep 28, 2007
    Grass Valley, CA
    Eminence PXB2:800
     
  17. It's a nice crossover, but not for a 4-ohm woofer load.

    For the 2x12 cab, you either go active, or roll your own.
     
  18. davio

    davio

    Nov 2, 2006
    Boston, MA
    ...or use the second output from a power amp (or a head with two power outs like the Ashdown LG1000) with a lowpass filter going to the second woofer.
     
  19. vlad335

    vlad335 Supporting Member

    Apr 14, 2003
    Latrobe, PA
    What happened to Greenboy?
     
  20. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Family business again, I think. His dad's in ill health and he was talking about going to see him a few days ago.
     



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