@jameslo Thanks for your reply.
Yeah, I think I did check up IAC driver. I checked 'IAC driver bus 1' in the MIDI settings window of Pd and clicked OK button, and I confirmed that there is an icon 'IAC driver' in the pannel of MIDI studio in my Mac. But still no sound output. MIDI messages are blocked in somewhere else. I couldn't find.

And, when using raspberry pi, I got the same problem too.

Hello, guys.

I am just starting PD now, but I am confronted at MIDI setup problem. I can't play MIDI algorithm. So I just opened up MIDI setup window, on the output devices I can't find 'AU DLS'. I am using Mac OSX. With MaxMSP, everything is OK. And when I choose 'to max 1', I can send MIDI messages from PD to Max without any problem. But, in PD window, I can't use GM MIDI. And I am afraid of not setting up MIDI part. Anybody can helps me out? Really appreciate it.