We have Server machine, this computer with Headphones, and we have Client computer, this is remote PC with music =) On Server we should first open port for listening connections from Client :
# on ubuntu
sudo ufw allow from <Client_IP> to any port 4656 proto tcp
# on fedora ( with firewalld )
sudo firewall-ctl --add-port 4656/tcp
note: port 4656 just for sample. you can use any port you want
than on Server, from current user add listening for connections