For tutorials which require audio input, one must first manually enable the microphone access option in projucer (for macOS, iOS and Android).
There’s a note in the tutorials mentioning this but, almost invariably, it will be overlooked by some slightly thick readers such as myself. The problem is that then there is no warning when running the code. The window asking for permission to use the microphone only appears if the setting has been enabled.
But what makes things worse is that once you have compliled the code, if you then enable the setting in projucer and reopen in Xcode, the window still does not appear. One has to manually clear the build folder first for this to happen.
It would perhaps be a good idea to add something to the corresponding note in the tutorials such as: “If you have tried running the code without previously setting this option in projucer, then please clear the build folder and try again.”