Cell phones have come a long way, but despite ever-advancing hardware, call quality over cellular airwaves still leaves a lot to be desired. You're probably all too familiar with the choppy, robotic, and static-riddled calls that sound like they're coming from a walkie-talkie, not a fancy new smartphone. Well, just like broadcast TV underwent a high-definition makeover, the next generation of cellular call quality is on the horizon, and it's called HD Voice.

Wondering what all the fuss is about? We've recorded some sample HD Voice calls and standard voice calls so you can take a listen and compare for yourself.

Every major carrier is working on bringing HD Voice to its customers, but not all HD Voice is created equal. Different carriers implement different codecs, so there won't be interoperability right out of the gate. T-Mobile, for instance, uses AMR-WB (adaptive multi-rate, wideband) through its existing 3G network, while Sprint uses EVRC-NW over its CDMA 1X Advanced network. Meanwhile, AT&T and Verizon are working on their own versions of HD Voice using Voice over LTE (VoLTE).

What does that mean for you? To start, you'll only be able to enjoy the benefits of HD Voice when calling someone else on the same carrier with a phone that supports HD Voice. Hopefully carriers will follow through with interoperability, but until then, you won't hear HD Voice if you're making a call out of your network.

T-Mobile has the most mature and widespread HD Voice implementation at the moment, so we decided to put it to the test and upload some samples so you can hear for yourself. For our HD Voice tests, we used an unlocked Nexus 5($259.00 at Amazon) with a T-Mobile SIM and an HTC One (M8), also activated on T-Mobile. We attached a microphone to the earpiece of the HTC One (M8) and connected it to a desktop computer that recorded our sample calls using Audacity. I made the first set of calls, reading some headlines from The New York Times aloud into the Nexus 5 mic. In a second set of calls, I set up a Bose SoundLink III($499.97 at Amazon) and played back Lil Jon's "Turn Down for What" with the Nexus 5 about four inches away from the speaker for both calls. For our standard call tests, I swapped out the T-Mobile SIM in the Nexus 5 for an AT&T SIM and repeated every test.

To clarify: We realize this isn't exactly a fair fight, since call quality between different networks can vary greatly depending on a number of factors. This setup allowed us to eliminate any discrepencies on the hardware level, and in each instance, signal strength for AT&T and T-Mobile was more or less equal. This is by no means a condemnation of AT&T's call quality—in fact, as far as standard calls go, these results were fairly positive.

Voice Samples:

Standard

HD Voice

Neither here offers pristine audio, but to my ear, HD Voice on T-Mobile delivers fuller, more natural sounding audio. My voice distorts at times, but generally sounds clean and easy to understand. The standard call doesn't sound terrible here, but you can pick up that distinctive robotic, distant quality that plagues most normal calls. There's still distortion and hissy sibilance, too, while you can hear a few clicks and pops throughout.

Speaker Samples:

Standard

HD Voice

Playing back Lil Jon's "Turn Down for What" using the Bose SoundLink III reveals an even bigger disparity. Again, neither sounds particularly good, but you can actually hear the music coming through the HD Voice call, while the standard call is a garbled mess of indistinct noise.

I made a number of calls to real people in the PC Labs in addition to these controlled tests, and every time I noticed a distinct advantage to HD Voice calls. While I'm not sure it's the same jump from standard-definition video content to high-definition, the results are definitely promising.

For more, read How to Buy a Cell Phone, The 10 Best Smartphones, and The Best Android Phones.

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