The word "grating" might fit because something that is "unsightly" could also be described as an unpleasant sound or something that is not good to our ears (a harsh sound). When something is grating, it's extremely harsh and irritating, like the grating sound of your alarm clock early on a Monday morning. As an adjective, grating is particularly good for describing unpleasant sounds, like the grating voice of someone who's nagging you.
: sounding harsh and unpleasant.
"a high, grating voice"
Here are some example sentences (from Oxford) -
‘The man had rambled at her too, in a gravely, grating voice, explaining who he was and where he was taking her.’
‘The rough grating voices tore through the darkness and pierced his ears.’
‘Then he laughed a harsh, grating laugh Kaitlin had never heard.’
‘With a harsh grating sound, the lid slid off, exposing its contents: a small black metal box, the size of a briefcase.’
‘There was a harsh, tinny grating sound, echoing into his ears, as the sphere ground against the wall.’