Workinonit,
In my unprofessional opinion, you would never ever hear a sound associated with piston rings, broken or otherwise. Because their job is to seal and scrape oil, any ring problem will be visible out the tailpipe or in poor engine performance, but not noise.
You stated your noise appeared suddenly. If this is accurate it almost precludes a internal 'wear' issue and points towards the failure of some component attached to the engine.
Using a short piece of heater hose as a stethoscope to find and pinpoint noises as the engine idles in the driveway may help isolate the sound. This is a common troubleshooting procedure and can produce great results...give it a try.
Stuart
