Author here. SignalKit is the DSP engine I extracted from my macOS audio app.

7 processors (EQ, compressor, limiter, LUFS meter, stereo widener, crossfeed, ring buffer) built on Apple's Accelerate framework.

Zero heap allocations in the process() path. Safe to call from a CoreAudio IOProc. No locks, no Foundation, no ObjC messaging.

Full pipeline runs in ~38 μs on M4 Max at 512 frames/48 kHz.

60 tests including DFT frequency validation and BS.1770 LUFS calibration. MIT licensed, zero dependencies.

The common take is you need C++ for real-time audio. This is my argument that Swift + UnsafeMutablePointer + vDSP works for this class of processor.