Thank you for the replies!
@whale-av That first link had the solution.
Thanks again!

Hello,
I'm just beginning to learn pure data....
I would like to work with sounds coming from an external input.
As I saw in a tutorial, I want to show the envelope of the sound coming from the mic.
Seems quite basic but... nothing is happening?!
Can someone help me out with this?
Here's a printscreen of all the different settings.
What am I missing???
Also, I checked with reaper, there is sound coming in through the mic. I closed reaper before opening pure data to make sure there's no conflict with the sound device. That didn't help though...

(i'm on mac osx 10.14.4 )