Biquad Filter Non-Linearity I'm using a biquad filter algorithm in my project. I got 3, 16 size variable arrays summing into one and then gets filtered.

Now i want to filter each array seperately and sum after that, which if the filter was linear wouldn't be a problem, but result is non linear after all.

Am I doing something wrong with this process or biquad's non linear in nature?

If latter is true, can you recommend a nice filter to implement in embedded C, and musical sounding as well? (Quality factor is a must)

I'm using this to generate coefficients 

http://shepazu.github.io/Audio-EQ-Cookbook/audio-eq-cookbook.html
Turns out I was using same state buffer and instance for all three filters.

Whenever an array finishes filtering, new filter uses the old state array for that different timeline and it results in non-linear outputs at the end/start of a new one.

I created different state arrays and instances for each different array and the problem got fixed. Working smoothly as intended now.