For what it's worth, I just recently upgraded from Nexus 5 to Nexus 6 and I have had absolutely no problems with the device, especially with call volume. Litera

For what it's worth, I just recently upgraded from Nexus 5 to Nexus 6 and I have had absolutely no problems with the device, especially with call volume. Literally everything is a step up. I wouldn't let this sour you entirely, if your device has a problem, return it for a new one. I had an issue with my Play-store-purchased Nexus 4's earphone jack, prolly my fault, Google replaced it within a few days, paid for shipping and everything. There are a lot of business decisions that go into applying resources to problems, and we can't all assume we know those business decisions and the circumstances that are involved with making them. This could be a very small but vocal segment of the nexus 6 user-base, if it is a small problem, it should be treated as small priority. Personally, as a type-1 diabetic, it sucks seeing research done specifically for type-2 diabetes, but, unfortunately there are less of us, so it's seen as a lower priority.