Speaker damage?

Hello, I was just setting up a new pair of speakers when I plugged the source's RCA connectors into the amp while the amp was already on. This produced some incoherent static - nothing too loud as the volume on the amp was only at moderate levels - but I'm still concerned this could have been bad for the speakers. The speakers are so new that I'm not familiar with the sound enough to know if it has changed. Could this have caused damage to them?

Thank you.
No. Only if you had the volume turned too high and there was clipping would you have damaged the speakers. It might sound awful but don't worry.
+1 shadorne

It is very hard to damage speaker, other than by clipping, as shadorne stated. Clipping creates a lot of high frequency energy that can burn out the tweeter.  
One other way to damage speakers is driving the woofers so hard, the former is bent from bottoming out. There's zero chance you did that in this situation.
Thank you for your responses! The amp was just at listening volume, so there wouldn't have been any clipping right?

Looking into it a bit more apparently RCA cables won't be properly grounded as they're being plugged in, which is what caused the sound. Does that change anything?

Thank you again.
Don't worry about it. You're fine.... Enjoy your new speakers.
Most likely nothing happened and everything is OK , but next time plug interconnects or speaker cables only when the amp is off.
One of the easiest ways to blow a woofer is with a high volume ground buzz -- loose RCA connections can do this very easily as I discovered to my cost with a pair of Magico V3s -- one reason to avoid those "twist to tighten" "collect chucking " WBT plugs, I've had too many where the shield has gotten loose
Folkfreak, that was what happened but if the volume was only at listening level or lower would there be any issue? What is the best way to tell if there was any woofer damage?
When I damaged my woofer it was immediately audible (buzzing sounds) -- but woofers are tough and you'd really be hearing it before they got damaged -- mine was a full volume short without any volume control.
The static you heard is no different in frequency range from the loud static heard between stations when running through the FM dial on a tuner. Speakers are meant to produce sound at rather loud volumes. What happened was that you were startled when you heard the sound. But your speakers weren't startled - they just did what they were supposed to do - and were not damaged in any way.