Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Audio Crossover Frequency Equation...

  1. Aug 22, 2015 #1
    Can anyone verify or correct this equation to work out the crossover frequencies of a three tier sound system please? I never was the best in my physics classes...

    (Please find attached "Crossover Freq.dpf")

    And thank you in advance for your time.
    Sorry about the way i have had to write it.

    Many thanks,


    Attached Files:

    Last edited: Aug 22, 2015
  2. jcsd
  3. Aug 23, 2015 #2


    User Avatar
    Gold Member

    I have no idea what you are doing. Why are you choosing those frequencies, and what is the point of your calculations? I'm totally missing something.
  4. Aug 23, 2015 #3
    Sorry, its hard to write in one foul swoop without getting too confusing.
    To set the scene: This is all in a free field environment (no variables) and i'm only picking these frequencies in particular so i can do the equation now and know i am correct.

    This is so i can just apply the equation with the correct frequencies on every different sound system that i use giving the best sound out of the speakers. (Just to add, I will also be taking the room into consideration after this process and not at this point).

    My objective is to split three tiers of speakers equality using a logarithmic (Log10) equation.
    The reason i have chosen these frequencies is because i know:
    - The bass drivers (speakers) go as low as 30Hz, in turn i want to roll off at a 24Db per octave slope. Thus choosing 35Hz as a rough estimate.
    - The tops (top speakers) go as high as 19000Hz and again i roll off at a 24Db per oct.
    - In between these two sets of speakers is a middle layer of speakers (mids) that overlap (frequency wise) both the tops and bass.

    When the speakers overlap it boosts the signal by 3Db so the idea is that i create the most flat frequency response from all the speakers combined by crossing the frequencies over at the value worked out by the equation i added before. Also at the point of crossover a -3Db attenuation is added to remove the unwanted boost.

    I'm not 100% sure i got the equation correct though, my maths and algebra skills are not the best. ;)

    I was always told in university that this was the correct way to get the least stress out of the speakers and the cleanest sound.

    Thanks for taking the time to read this, its greatly appreciated.


    Ps Attached is a picture of the sort of sound systems i am currently using.

    Attached Files:

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook