The simplest possible circuit to generate a sound... (beginner)

[WahwaH]

Hello people!

      Lately I got myself very much interested in building my own
      stuff to synthesize a sound.
      As I am just a beginner, all the schematics I have seen so far
      are very complex and I don't think I could build anything like
      that.

      For the beginning I would like to ask you:
      What is the simplest circuit that would generate a sound (any
      sound - saw, square, sine... doesn't matter)? Could someone
      please show me schematics of such circuit?

      I mean it should say "ZZZZZZZ" when I turn it on, and also
      hopefully there would be a potentiometer to control it's pitch...

      If I build it correctly, later I would step into filters.

      Please understand me, right now it is terribly hard for me to
      look at these complex schematics for generating beautiful
      sounds. I need something simple to generate a beep or zzzz.

      Also, would this be possible with a 9V power source? (If not -
      that's ok, I'm just asking). ;-)

      THANK YOU IN ADVANCE!

Best regards,
   Vytis Puronas / WahwaH                       mailto:vip at takas.lt