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Please expand on something Vance Dickason merely brushed over.

Discussion in 'Amps and Cabs [BG]' started by Petebass, Jan 22, 2005.

  1. Petebass


    Dec 22, 2002
    QLD Australia
    In his chapter on vented enclosures he talks about filtering out frequencies below Fb and gives us this diagram for a passive subsonic filter:-

    -------Capacitor 1-----|------Capacitor2----|----------
    IN........................Resistor1 ................Resistor2..........OUT

    He makes no mention of what frequency it starts to operate, or the slope of the filter. I like the idea because using resistors in place of inductors will significantly reduce the bulk of such a device.

    Does anyone know how to calculate the cap and resistor values for these types of filters?
  2. Trevorus


    Oct 18, 2002
    Urbana, IL
    I didn't think about resistors, but the problem with them is that they are hard to get in high enough power handling capacities. Unless you plan on using this in an effects loop as a line level filter.
  3. Jim York

    Jim York

    Oct 27, 2004
    That diagram is one of a filter for use between a pre-amp and power amp, not one in a speaker cabinet.
  4. Trevorus


    Oct 18, 2002
    Urbana, IL
    That is what I thought. Do you know the math there by chance?