Another guitar tech question

[Born to Lose]

I have a question about guitar feedback. How is it controlled? I watch live performances by, say, Pearl Jam, or Rise Against, or Social Distortion and their guitars feed back constantly live. Even in the studio. I know feedback is caused by the guitar being on and the strings being allowed to vibrate freely.

But then you have Neil Young, whose guitars seem to feed back in-between notes in solos. I know distortion can be behind this, but it seems to happen much more quickly than the strings would be able to get themselves vibrating.

And then on the other end of the spectrum is Bruce Springsteen, who just lets his guitar hang there, plugged in, volume knob on ten, and there is no feedback sound at all.

What

 

[Rattlesnake Rock n Roller]

There is two types of feedback, the musical type where the strings are vibrated by the volume from the amp and is usually a pleasing feedback and sounds cool.
Then there is Microphonic feedback which is caused by the windings in the pickups vibrating at very high frequencies causing a squeal and this is not musical and unwanted. It's rectified by "potting" the pickups of the guitar. The pickups are removed and dipped in melted wax and the wax finds it's way into the windings inside the pickups coils and stops them vibrating microphonically.

 

[Born to Lose]

Oh, so a guitar can be feedback proofed?

I actually like the screeching sound that guitars make sometimes.