My wife and I both have the S8. While driving, I will connect my phone to the Bluetooth receiver in my car, and we can talk that way, at least until she tried to use her speakerphone so she can have her hands free. Once she does that, she quickly becomes muffled, to the point where it sounds like she has a stack of pillows over the phone. If I disconnect from my Bluetooth, or she she turns off speakerphone, the call quality becomes more acceptable. We have both tried resetting our phones, and neither of us uses HD/WiFi calling. I get the same results if I use an aux cord btw, so it doesn't seem to be on my end, and obviously holding my phone while driving is right out of the question. Need help before these phones go through the wall.