Which Netgear Prosafe switch is it exactly? Are you sure that there is no loop in your network design?
I would disconnect everything but Phantoms, Dialog, Internet connection and a PC / Laptop from the main switch. Then I would try listening online music just with this basic configuration.
I would disconnect everything but Phantoms, Dialog, Internet connection and a PC / Laptop from the main switch. Then I would try listening online music just with this basic configuration.