(taking it back to the list)
So, just to be clear, are you actually saying that PD's audio internals *are* multi-threaded?
Of course they are! Otherwise we wouldn't need the lockfree ringbuffer :)
The only occurrences I find in (0.53.1) of pthread_create() are in d_fft_fftsg.c and d_soundfile.c. Where and how is the audio thread created? How many audio threads are there?
The audio thread is created implicitly by the audio backend. Typically, there is only a single audio callback and thus only a single "audio thread" per application.
However, an application may create additional helper threads to spread DSP computation across multiple course. This is done by most modern DAWs. Another example would be Supernova, the alternative SuperCollider server by Tim Blechmann.)
Christof