[matthewmcg]

It's a shame that a lot of this innovation, while radically increasing flexibility and dropping cost, has degraded call quality.

On the other hand, calls between certain compatible LTE handsets (AT&T calls this "HD Audio" in my market) sound far better than classic landlines ever did. Ditto for good Skype calls and Facetime Audio.

[umeshunni]

> AT&T calls this "HD Audio"

I believe the generic term is VoLTE - https://en.wikipedia.org/wiki/Voice_over_LTE

[pilsetnieks]

Not really. VoLTE is Voice over LTE[1], which most likely implements HD voice (wideband audio[2],) however, with carrier and device support HD voice could be done over 3G and 2G networks as well.

[1] https://en.wikipedia.org/wiki/Voice_over_LTE

[2] https://en.wikipedia.org/wiki/Wideband_audio

[kristofferR]

VoLTE will actually soon feature Enhanced Voice Services (EVS), or Full-HD Voice, which is a vast improvement over "regular" HD Voice.

EVS is supposedly transparent and full-band. http://spectrum.ieee.org/telecom/standards/full-hd-voice-wil...

[davidf18]

VoLTE is great -- I use it on Verizon. But at least with Verizon it is turned off by default and most people don't seem to turn it on. It is turned off by default because LTE coverage is not as complete as the legacy 3G coverage (yet).

Facebook audio as others have pointed out is great.

[r00fus]

T-Mobile had it from 2013 and earlier (they got the iPhone5 in 2013 and it supported HD Voice). Call quality can be like a clear Skype.

[cpach]

Facetime Audio is great. Very big difference compared to a regular cell phone call.

[ryanmonroe]

With iOS 9.3 you can set WiFi calling as the default (when wifi is available).

[cpach]

Didn’t know that. Neat :)

[lucaspiller]

There are good quality codecs available that use less bandwidth and have better quality than traditional phone calls, but they are encumbered by patents and license fees. Most people just care about getting a service cheaply/free rather than the actual quality, so most providers will just use the G711 (what landline phones use for trunking) or GSM codecs which are free to use. G722.2 (AMR-WB or "HD Audio") provides a better quality at less than half the bandwidth of G711, but it isn't free to use so very few providers support it.

Not only that, but the codec needs to be supported at all stages of the call (the phones, the VOIP server, the trunk if external, etc), and if not it'll need to be re-encoded, which uses more CPU and reduces the call quality. As such you are probably better off just sticking with a more common, lower quality, codec. It's a chicken and the egg problem as providers won't support more codecs until hardware does and vice-versa (Twilio's SIP trunking service only supports G711, which is kind of the lowest-of-the-low).