Ask HN: How do people working on advance technologies get their help?

I am a web developer and have always got my problems solved with Google or Stackoverflow. Sometimes, I have got stuck for long hours but only for my own silliness. I believe that is because the web operates on much higher level of abstraction and has an extensive community online.

I wonder how do people working on advanced / low level realms of programming like audio processing, embedded computing or robotics get their help? provided the online community is quite small since you are dealing with a specific low level kind of programming.