Have you ever noticed that call quality on your iPhone 6 is rather inconsistent? You call someone up and it sounds great — almost like they’re in the room with you. However, you then call someone else and it sounds like the plain awfulness that you’ve been accustomed to over the years. Why is this?
You may think that the better call quality that you sometimes get is a new iPhone 6 feature, and that’s partially true, but that amazing crystal-clear call quality is actually a carrier-specific feature called HD Voice.
However, in order for it to work, a phone has to support HD Voice, and the iPhone 6 and iPhone 6 plus both do, meaning that you’ll get better call quality and the person you’re talking to will sound way better than you were used to. Why, though, does this excellent call quality not work all the time?
The simple answer is that in order for HD Voice to work, yourself and the person you’re calling both need an iPhone 6 or iPhone 6 Plus and must be on the same carrier. Even if you’re on Verizon and have an iPhone 6 and your caller is on a Sprint iPhone 6, it won’t work, even though both carriers feature HD Voice.
The iPhone 6 and the iPhone 6 Plus aren’t the only Apple smartphones with HD Voice support, as the iPhone 5s, iPhone 5c, and the iPhone 5 come with support for HD Voice as well, but even then, it depends on the carrier as far as what devices it will support.
So as long as both callers have one of these devices and are on the same carrier, HD Voice will be enabled for both parties, allowing for crystal-clear call quality. Verizon, Sprint, AT&T and T-Mobile all support HD Voice.
What exactly is HD Voice, though? HD Voice is also technically called wideband audio, and it essentially extends the frequency range of audio signals that it can transmit, resulting in a wider frequency band being sent through the air (hence the name).
To put it simply, a normal phone call with any cell phone will only transmit certain frequencies of your voice while you talk, and that frequency band is rather limited with normal phone calls. This results in pretty crappy call quality most of the time. However, with HD Voice, the phone call can transmit wider frequencies, meaning more of your voice is transmitted through the air to the other side, resulting in way better call quality.
Some carriers, including Verizon, AT&T and T-Mobile also have what’s called VoLTE (Voice Over LTE), allowing phone calls to be sent through LTE rather than traditional cell towers. Verizon, for instance, has something called Advanced Calling 1.0, which is enabled through VoLTE and consists of a suite of features that include HD Voice, simultaneous voice and data functionality, and the ability to have conference calls with multiple callers. Advanced Calling 1.0, however, only works with the iPhone 6 and iPhone 6 Plus as far as Apple devices are concerned.
Sometimes, VoLTE is automatically enabled on your iPhone out of the box, but if not (and Verizon requires that you opt-in), you can enable it by going into Settings, tapping on Cellular and then Enable LTE. From there, select Voice & Data.
The best part about VoLTE and HD Voice is that it doesn’t cost extra, so enabling it won’t increase your monthly bill or change anything. It’s essentially a free feature that carriers are now including in all cellular plans, and it’s worth it to enable HD Voice.
At that point, if you and your caller both have iPhones that support HD Voice and are on the same carrier, you should experience excellent call quality. Otherwise, you’ll be bothered with the regular crappy call quality that you’ve had to suffer through for years.