Improved audio quality is a hard thing to measure. Lots of cell phone carriers claim to have it. But only T-Mobile and Verizon actually offer nationwide VoLTE (Voice over LTE) — the relatively new calling standard that, when possible, places calls over 4G LTE data networks, instead of the traditional circuit-switched networks.
We’re still a long ways away from the day when you’ll get pure HD voice with every phone call. These days, there are so many limitations that HD voice may not actually be very noticeable. Nevertheless, our guide will give you everything you need to enable HD voice on your iPhone 6. We’ll also outline the limitations. Thankfully, those limitations are shrinking. Expect to see more VoLTE ready phones in the next few months.
By default, your iPhone 6 limits 4G LTE network to “Data only.” To enable HD voice, you’ll have to configure your iPhone 6 to have voice and data sent over the 4G LTE network. This means you will need to manually enable VoLTE. From your iPhone 6’s home screen, go to Settings > Cellular > Enable LTE > then select Voice and Data.
iPhone 6 users with T-Mobile contracts can enjoy the simple, one-step activation of HD voice (there are lots of limitations, see below). Not the case when you’re under contract with Verizon. It added an additional step called, Advanced Calling 1.0. Both the Verizon and T-Mobile offer VoLTE services at no extra charge.
To activate Advanced Calling 1.0, log on to your Verizon account > Manage My Account > Change Features > Add Advanced Calling.
AT&T: AT&T provides limited HD voice service. Currently, HD Voice is available in Illinois, Wisconsin, Indiana, and parts of Minnesota.
Sprint: Sprint does not offer HD Voice over VoLTE.
Okay, so HD Voice sounds pretty good. But here’s the deal, HD voice will only happen once in a blue moon. VoLTE is still new. And many HD Voice and VoLTE connections frequently drop calls. That’s because both lines engaged in the HD Voice conversation have to remain in a LTE network for the duration of the call. The call will drop if one line leaves the 4G LTE network or the connection becomes too weak.
What’s more, HD voice will only work when both callers are using VoLTE ready phones on the same carrier. Aside from the iPhone 6, only a few other VoLTE-ready devices are currently available, including Samsung Galaxy S5 and the Galaxy Note 3.