Same exact issue. "You sound like you are in a wind tunnel." I took my '18 Model 3 Performance to the service center and had them try to diagnose it. We took a drive and called in to the shop while going 80. Of course the person on the other end heard us "just fine." We tried with my Samsung S9 and his iPhone-something. He showed me a setting in the iPhone, I forget what it was, that he says helps iPhones. Some headset setting... But I think that is bogus. I was leaving it for some paint work, so he told me he was going to check all of my seals with "ultrasonics." Probably also BS just to shut me down. I told him, OK, I would leave myself some voicemails at different speeds and go from there.
He then offered that a good fix "if all else fails" is to pop the mic assembly off with a flathead screwdriver and pack some insulation around it. To me, that all but admitted that it's a known issue with the mic picking up road & wind noise. I'm not sure where I will go from here, but I am complaining to Tesla not over "road noise," which they seem to classify as subjective, and more to, "Bluetooth handsfree phone is not usable."
It sounds like, from these posts, the problem might not be fixable at all. For what it's worth, I was thinking it was the wind noise but now after that test drive with him, I am wondering if it is more road noise from the tires. We drove on a new road but my complaints generally come from a road with more noise.
I'll post again if I get anywhere with this, either by capturing it fail in voicemails and getting service to fix it, or if I go on my own and pack something around the mic..
H