Midwest Audio Fest

It’s that time audio enthusiasts! Registration for the 2019 Speaker Design Competition is now open! Visit for details and to list your speaker project. We are excited to see all returning participants, and look forward to meeting some new designers this year, as well! Be sure your plans include a visit to the Parts Express Tent Sale for the lowest prices of the year, and the Audio Swap Meet where you can buy and trade with other audio fans. We hope to see you this summer! Vivian and Jill
See more
See less

BSC Question

  • Filter
  • Time
  • Show
Clear All
new posts

  • BSC Question

    Quick question. In thinking about a paralleled resistor/inductor placed in series with a driver, I understand that the resistor's value determines the amount of high frequency attenuation. But (all things being equal) does an increase in the inductor's value shift the filter's midpoint frequency higher or lower?


  • #2

    Look at it as if you are effectively rolling off the "Highs" at a 6db/octave rate. A big inductor will start the rolloff lower in frequency.


    • #3
      Makes sense when you explain it that way. Thanks!


      • #4
        Originally posted by fernandov View Post
        ... does an increase in the inductor's value shift the filter's midpoint frequency higher or lower?...
        The inductive reactance of an inductor increases as the frequency across it increases therefore inductive reactance is proportional to frequency ( XL α ƒ )
        Simply it is a low pass action - larger value, lower frequency
        "Not a Speaker Designer - Not even on the Internet"
        “Pride is your greatest enemy, humility is your greatest friend.”
        "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."


        • #5
          extra thought: (except for "notch" type filters: LC/LCR - anytime both an inductor AND cap are involved - I THINK) whether in series or parallel (shunt to gnd) and regardless of filter type (LP, HP, or BandPass), LARGER (uF OR mH) always involves a lower Freq., and (vice versa) smaller is higher.


          • #6
            I know you already have your question answered. However, I have found this tool can be helpful as a good starting point for a BSC:
            All about Speaker Design YouTube Channel