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Is there an understandable explanation of “feedback” for normal people?
Plug a microphone into the AUX jack on your stereo, and then hold the mike in front of a speaker – that screech you hear is audio feedback.
If you hit a bell it makes a ringing tone. Any given bell always makes the same tone – the principle of church bells. If you set a sound system to output that same tone, the bell will start to ring in sympathy – also feedback. But in music, we say that the bell resonates, but it is the same thing.
All systems from a simple bell to a complex sound system have at least one resonant frequency where the note continues at the same frequency for as long as energy is supplied – positive feedback. Bad sound systems (and bells) have more than one resonant frequency.
Non-resonant frequencies die away much faster than resonant frequencies, so much more energy is required to maintain that particular sound. That is negative feedback.
Finally, if you hit a bloke down the pub, he will probably hit you back – feedback, but not as we know it 