Introduction to Digital Filters



Although I have a background in electrical engineering and programming, Audulus was really my first serious exposure to musical synthesis in general and digital synthesis in particular. I had played with other plug-ins, but never really considered the actual code producing the sound. When I discovered Audulus, I soon realized that the underlying mathematics were more complex than I had thought. After puzzling over some of SansNom’s excellent filter designs, I decided to do some further study. Even though I had been exposed to most of the math before (a very long time before!), I struggled to understand many of the papers. This is an attempt on my part to help others who are not familiar with calculus to understand the basic principles as it applies to filters. In the tutorial I cover basic integration, and how it applies to a simple RC filter circuit, and then show how these same principles can be applied to a digital signal by constructing a digital model of the filter. I have included the examples as an Audulus file as well for your reference. I hope you find it useful. I would like to thank @biminiroad and @robertsyrett for their generous help and encouragement.
Introduction to Digital Filters.pdf (1.4 MB)
Intorduction to Digital Filters.audulus (103.0 KB)


This is an amazing intro to digital filters and really helped me learn a lot! Required reading for anyone who’s interested in building their own digital filters in Audulus.


This is great, thanks for putting it together!


That’s awesome - you did a great job at reducing many college classes into a succinct, yet understandable document. This takes me back to college, and working through the same math (including the calculus and the various other methods of determining area under a line), but I’m sure you know as well as I do how complex (sic) the math can get when you start looking at filters in greater detail.