How to make an Audio Equalizer

Thread Starter


Joined Mar 3, 2017
Hello everyone, i just want to ask on what to do first in doing a baxandall audio equalizer. Our professor just give us a 5 center frequencies which is 100hz, 320hz, 1000hz, 3200hz and 10000hz as a given. What to do? Thank you.


Joined Jan 3, 2011
I would assume you've received some sort of information in the course that is applicable to the problem. Start there. Or Google "Baxandall EQ".


Joined Apr 5, 2008

Baxandall will say that the tone control is done in the feedback of an amplifier.
Most circuits for Baxandall tone contol have only 3 frequencies.
I never have seen any circuit with more than 3.

If you want to have more frequencies, look for a graphic equalizer, but that will likely not use the baxandall circuit.



Joined Feb 5, 2010
Use 5 single freq "tone" controls, built baxandall style, feeding a five input summing amp and a follow on power amp to give +4 dbm at full volume.

That will be $40.00 for the engineering advice. :)


Joined Jun 17, 2014
Hello there,

One way to approach the problem is to examine a circuit that is already made, analyze it, understand it, and then modify it to fit your need. This is a typical way to start with a circuit that has already been invented and in widespread use. For an equalizer you would want to change the center frequencies and channel spacings for example.

Another way is to look into sub circuits that may be used in your final design such as a gyrator. Once you understand that circuit for example you can then go on to create larger value inductors for use in tuned circuits that would be used in an equalizer circuit and dont actually require the use of any inductors. If you are allowed to use inductors then you may not need this but i cant know that unless you tell me.