To weigh in with an opposite opinion: if you make audio software, please, don't spend your time on reimplementing audio filters. It takes time and focus from things your program just has no way of doing with 3d party plugins. There's an over-abundance of audio processing plugins of various kinds and it's much easier just to support LV2 or VST (or, maybe, Clap, if you're optimistic about its future).

If you must bundle something, just add a JSFX interpreter and bundle a bunch of JSFX scripts. Your power users will thank you for it.