Hi Phil,

first set its audio API to portaudio, then switch DSP on?

Yes

I tried that, and still get no sound output.

But, do you have the "unknown API error" on the Pd window?

If not, check the in/out channels on the subprocess' Audio Settings menu and set them to match your system.

I would also "Save all preferences" (or "save to" if you need them in a file) after finding the correct settings.