How to Build Audio Filter Circuits - Circuit Basics
Design Low-Pass, High-Pass, and Band-Pass Filters in Browser in Minutes | via @adi_news « Adafruit Industries – Makers, hackers, artists, designers and engineers!
HF auto bandpass filter controlled by Arduino (real test) - YouTube
Active Low Pass Filter RC applied in Projects with Arduino - Hackster.io
Minimalist low-pass filter library – Martin Bloedorn