Zing Systems, a Mountain View company developing WiFi mobile audio and entertainment devices that are “always connected,” and which don’t require connection to a PC, has raised $13 million in a third round of funding, according to VentureWire.

The funding, which closed last month, was led by new investor IDG Ventures Boston with participation from previous investors Redpoint Ventures and Camp Ventures. Zing Chief Financial Officer Doug Sinclair said the company has now raised less than $20 million to date, VentureWire said.