Sallen-Key Topology, MFB and Butterworthy in Bandpass Design for Audio Circuit Design

This paper succinctly studied active filter topologies: Sallen-key circuit, MFB and Butterworth in band pass design for audio circuits. It has been able to identify distinctive suitable features with applications in audio frequencies range. The work also serves as a foundational study for an advanced work on active audio filters. Sallen-Key pluses with quality factor (Q) that can be varied via the inner gain (G) without modifying the mid frequency (fm). Notably, the Q and Am cannot be adjusted independently. Butterworth, maximally flat magnitude response in the pass band, has monotonic amplitude response with an excellent flat pass band, less phase shift, and better transient results.