Newbie needs advice - poor voice quality on new 710

I did some searching. Apologies if this has been asked before. I just picked up my new 710 at verizon yesterday after trading in my dinosaur nokia 918. The problem I'm having is voice quality. The caller's voice is loud enough - much better than the Nokia, but the voice tone seems to faintly warble in the background like someone's turning the tone from bass to treble and back or changing frequencies or something. Not hugely blatant, but it's beginning to really bother me. My analog phone never did this. I'm not feeling good about this phone, but maybe I'm overreacting. I need some solid advice from someone who's lived with this phone awhile. Do I have a bad one or do they all do this? Should I take it back? Any help appreciated.

you talking about when you talk you hear the warble? If so, you need to turn down your talk volume. Sounds like your getting feedback. Also, you might try and turning down the earpiece volume also, as it might be getting picked up by the mouth piece.

No, not when I talk. It's when the other person is talking. I turned down the handset volume, which helped a little bit, but the phenomenon still happens.