Explore the fundamentals of analog filtering in this comprehensive DIY synthesizer tutorial. Delve into the construction of a voltage-controlled filter (VCF) from scratch, with detailed explanations of component functions suitable for beginners. Learn about passive first- and second-order high and low pass filters, oscillation basics, and filter analysis. Follow along with the provided bill of materials to build your own low pass and high pass filters. Discover how to adjust cutoff points and create higher-order filters. Perfect for synthesizer enthusiasts and electronics hobbyists looking to deepen their understanding of analog audio processing.