Resonant filters
Filter Circuits with Capacitors
Bode Plots
Project 170
operational amplifier - Is the cut-off frequency of a 4th-order filter at -12 dB or -6 dB? - Electrical Engineering Stack Exchange
6dB Passive Crossovers
How to design Shelf and Butterworth HP or LP 6db/oct, 12db/oct filter? - Q&A - SigmaDSP Processors & SigmaStudio Dev. Tool - EngineerZone
What makes 6dB filters so special – Just Blogging
How do speaker manufacturers calculate the -6dB frequency cutoff? | Audio Science Review (ASR) Forum
Solved: 6 dB/octave highpass Butterworth problem - NI Community
Filter slope - Apple Support
Roll-off - Wikiwand
Why do the orders of hi/low pass filters go in 6 dB increments? - Sound Design Stack Exchange
Analog filters
Linkwitz–Riley filter - Wikipedia
What makes 6dB filters so special – Just Blogging
Spectrum Analyzer Basics: Bandwidth - Siglent
Further With Filters
High-Pass Filter - Audacity Manual
Analog filters
Audio Filters -- Theory and Practice
First Order Passive Crossovers, 6 dB per Octave
Should the slope of your filter be 6, 12, 18 or 24 dB per octave?
First Order Passive Crossovers, 6 dB per Octave
