Passive Filter (High Pass) for Sub Question

Discussion in 'Archived Threads 2001-2004' started by Anthony AC, Mar 12, 2003.

  1. Anthony AC

    Anthony AC Extra

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    OK, I'm a newbie so go easy.

    Planning my DIY sub, I find that below about 19 Hz the driver goes into excursion overdrive. Hence as is commonly recommended a HP filter at just above this point is a good idea. Can someone tell me if at a 4 ohm sub impedance and wanting a crossover at 20 Hz, why I cannot just install a 2000uF cap (2200 available) as a passive filter after the amp and before the driver. I know (after reading [​IMG]) that the driver will vary with impedance at different frequencies but at this low a figure won't it be pretty stable at the rated value? Can I just do this?

    Any advice would be appreciated. Thanks, Anthony.
     
  2. Isaac C

    Isaac C Stunt Coordinator

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  3. Dave Milne

    Dave Milne Supporting Actor

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    Assuming for a moment that the cap would work (which it won't, as Isaac demonstrated)... Rod's rumble filter will give you 36db/oct rolloff (instead of 6) and cost less than a 2200uF, 100V, non-polar capacitor (if you can even buy such a thing). Electrolytics are polarized and unacceptable as pass elements in audio applications.
     

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