Thank you both for your prompt response and assistance! The tires are a soft summer variety, type: Continental Sport Contact 2's. They haven't been rotated and appear to be on the correct sides. There still is quite a bit of central tread, with the side tread somewhat worn towards the very outer edge of the sidewall.
As for natural sounding, it def does not sound "natural" but neither mechanical, as might be the case if it was a grinding sound. It definitely was not originally there.
After hearing your thoughts, I will pay attention to the tires to see if they are the culprit. On the other hand, when I lower my head towards the rear interior carpet above the glove right in front of the engine, the sound seems louder?
I'll let you know what I come up with after closer observation when driving.
Thank you!
