Pure Data externals for Mac.

fumio~: simple digital model of the Korg MS20 filter, derived from Miller Puckette ~bob (4th order Runge-Kutta)

ota~: simple digital model of a classic 4-pole OTA filter,  derived from Miller Puckette ~bob (4th order Runge-Kutta)

ring64~: extremely stable 64-band resonator

zdsv~: zero-delay feedback state variable filter