Are the AudioObject APIs (such as AudioObjectGetPropertyData, AudioObjectSetPropertyData, etc.) thread-safe? Meaning, for the same AudioObjectID is it safe to do things like: Get a property in one thread while setting the same property in another thread Set the same property in two different threads Add and remove property listeners in different threads Put differently, is there any internal synchronization or mutex for this kind of usage or is the burden on the caller? I was unable to find any documentation either way which makes me think that the APIs are not thread-safe.