"They are listening to music."
Translation:One słuchają muzyki.
Take note that słyszeć and słuchać are different verbs, the latter requires genitive.
Grammatically ok but somehow illogical. They are listening in a manner that is determined by the music. One can „tańczyć do muzyki” (to dance and match the music with moves). One can also „śpiewać do muzyki” (to sing, and to fit to the music). But „słuchać do muzyki” is as I said, illogical.
We cannot directly substitute one preposition for other and expect that all will be fine. It doesn't work with preposition.
I was using 'do' as English 'to' as i have learnt is used when going 'to' somewhere. Your description in this context is more like 'with'. I now realise the context of use is different. 'To' a location, for which we use the same word when listening 'to' music but in Polish, not a context for 'do'.