AudioKit is quite good, but it's a third-party solution that covers a fairly defined problem domain. And while the AudioKit devs are among the most experienced

AudioKit is quite good, but it's a third-party solution that covers a fairly defined problem domain. And while the AudioKit devs are among the most experienced Core Audio developers around, even they are frustrated by the lack of documentation. See, e.g., [1], where they say: "The most important example of this is that we don’t really understand at present how to create AUs which have polymorphic input and output busses. [snip] This is fundamentally because the Apple documentation on how this is supposed to work is essentially non-existent. I undoubtedly leverages the fact that the input and output busses are KVO compliant, but this is about as much as we know. We will have to figure it out via experimentation." [1] https://github.com/AudioKit/AudioKit/blob/master/docs/AudioUnitCreation.md https://github.com/AudioKit/AudioKit/blob/master/docs/AudioU...