In life, music was a distant thing heard during village festivals. There were no radios, no instruments, in the Kurosaki household, and while servants would hum under their breath, nobody dared sing.
The silence couldn't distract Hisoka from the press of other people's emotion. He learned to listen for the rhythms in the wind, the high and low notes of the old house creaking, the percussion of footsteps and rattle of carried objects. He could sink into sound, anchor himself against the pain of contact.
"Hisoka," Tsuzuki says.
Hisoka focuses on the music of the voice, lets Tsuzuki touch him.