I couldn't hear the young lady's voice clearly enough from the SYNC/navigation system in the Edge ST. She sounded like either she, or me, was underwater. I came to the conclusion the voice only originates from the center dash speaker. So I replaced it with a better one. The one I chose for the upgrade is an Infinity Reference REF-3032cfx Reference Series 3-1/2" 2-way car speaker.
I'm amazed with the voice clarity now. The OEM center dash speaker was a cheap paper one and it's magnet was so weak it wouldn't hold a paper clip. I didn't find that the center dash speaker contributed much to music... maybe none, if it does it would only be an improvement as well.
Any way, I only used one speaker of the pair and would like to sell the other (one) speaker, it's new in the box and has never been installed.
I'm asking US $50 including shipping.