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What's so great about Cast-frame woofers?

Discussion in 'Amps and Cabs [BG]' started by Woodboy, Jan 22, 2004.


  1. Woodboy

    Woodboy

    Jun 9, 2003
    St. Louis, MO
    Most of the higher priced cabs use cast-frame woofers. Are these necessarily better than stamped frame woofers? Does the cast frame mean higher power handling?
     
  2. Nick Gann

    Nick Gann Talkbass' Tubist in Residence

    Mar 24, 2002
    Silver Spring, MD
    I dunno, but mine sound awesome :bassist:
     
  3. Cast frame drivers have one distinct advantage (among others) over stamped frame drivers:

    If the cabinet or driver is ever dropped, the cast basket is much less likely to deflect (bend) and will likely perform just as it did before the physical shock.

    Drop a cabinet or driver with a stamped basket, and the weight of the magnet may deflect (bend) the frame and the speaker will never work right. Once you misalign the magnetic gap in relation to the voice coil, game over. In the dumpster.

    Then again, if you treat your gear kindly (as we all should) this problem is not likely to happen, regardless if your baskets are stamped or cast.

    FWIW
    b

    :)
     
  4. notanaggie

    notanaggie Guest

    Sep 30, 2003
    Cast frames are usually aluminum, so they don't "steal" any of the magnetic field from the magnet structure. That probably isn't a big deal.

    They also are more rigid, so theoretically they should be better at the infamous "transients" that were discussed elsewhere. A springy stamped frame may deflect a bit and absorb some energy that would go into the cone. Maybe not a huge effect either.

    But, being aluminum, a cast frame is a big heatsink, and can let the speaker handle more power, by keeping the magnet structure cooler. A cooler magnet structure sucks more heat out of the voice coil, keeping it cooler, and so allows higher power without "power compression".

    When the V.C. gets hot, its resistance goes up, and its sensitivity drops. May be as much as 3 dB, which cuts your power in half. The V.C. might be at 300 deg F, which is pretty hot. With the temperature coefficient of copper, you could figure out what increase of resistance that would be. I'm too lazy to figure it though.
     
  5. As with everything else, there is a flipside to this. As stated above, cast framed woofers are usually better due to increased frame rigidity, the ability to disipate heat, and higher strength to weight ratios. Unfortunately, some no-name (or even cheaper brand-name) woofers use poor castings which actually make them inferior to stamped frame ones.

    Some companies will do anything for marketing!