Voice Quality on Smart Phones Still Sucks (2014) | Hacker News Reader

Voice Quality on Smart Phones Still Sucks (2014)

consumerreports.org

56 pointsmhb45 comments

Cell quality of GSM/CDMA or others isn't good but the article ignores all the Wi-fi calling, FaceTime Audio and VOIP type calls you can make on a smart phone now. I've found that those are substantially better quality than any landline or cell.

If you want to know the real reason for this, it's because normal cell calls still have to go over POTS (https://en.wikipedia.org/wiki/Plain_old_telephone_service) on the backend, which typically uses 8-bit mu-law companding of audio at 8kHz. This compresses the typical frequency range for phone calls to 300-3000Hz, which is a lot smaller than the real range of human hearing, although it covers the range used by human speech so it was considered totally acceptable before unreliable wireless packeting became the typical last leg.

VoIP, FaceTime, Skype and other IP-only technologies can use much better audio codecs, going all the way up to CD quality audio (44kHz, 16bit). This makes a huge difference when there is background noise and clipping and less than optimal transmission conditions.

(Source: I used to work for an IVR company.)

I'd argue that 64 kbit PCM performs significantly better than most compressed codecs in high noise situations, I don't consider it a benefit to include audio up to CD quality for a conversation on the phone, because much of what you do include is unwanted/unneeded noise.

That doesn't really explain why smartphones (and cell phones in general) sound so much worse than landlines, does it?

It's the combination of wireless packets dropping and the audio having to be degraded to 8bit/8kHz to pass between carriers that really brings on the terrible. It's kind of like TCP over TCP [1] -- works well enough a lot of the time, but when it fails, it fails badly because of how the two layers aren't really built for each other.

[1]: http://sites.inka.de/bigred/devel/tcp-tcp.html

POTS lines do not carry more audio bandwidth than a cell phone. All of them are 64kbit PCM uncompressed audio.

Ah, ok, that makes more sense.

Compression largely, EVRC and GSM (CDMA and GSM respectively) are pretty heavily compressed, while I prefer the sound of EVRC, both are compressed - another thing to point out is most smartphones are pretty lousy telephones, bad earpieces, poor microphones, and so on. If you want to see how cellular handset can perform, use a good communications grade handset.

Any recommendations or examples of "good communications grade" handsets?

> This compresses the typical frequency range for phone calls to 300-3000Hz, which is a lot smaller than the real range of human hearing, although it covers the range used by human speech so it was considered totally acceptable before unreliable wireless packeting became the typical last leg.

But... landline telephones have always mangled human speech. They're awful.

I deal with a ton of cell towers interconnected with Ethernet over fiber [ Ethernet point to point built on MPLS ]. I am not sure about cell towers over POTS but I dont think thats how its done now.

Thats not to say there arent legacy towers out there on POTS, but all new towers are on Ethernet via fiber as far as I can tell.

Sure, you can connect the towers to the carrier however you want, and this is why certain carriers can sometimes hack in better quality protocols within-network (see the discussion on voLTE further down the page). Carrier-to-carrier connections, however, still have to use POTS/PSTN (since, if you send a voice call to another carrier's network, you can't a priori know it's a smartphone vs. a landline vs. something else right now, and PSTN is the only standard they all agree on). I agree, it's dumb.

Also see https://en.wikipedia.org/wiki/Public_switched_telephone_netw... regarding the 64kbit/s limitation.

I've usually found POTS-to-POTS calls to sound much better than latest-iPhone to latest-iPhone telephone calls. Why can't cells at least get to that level?

Also since the article has written, VoLTE has launched on many networks which is a huge improvement

My brother accidentally called me with Hangouts the other day and the quality was just shockingly better. I've started using it instead of a regular call where it makes sense (i.e. the other person is on hangouts+wifi too, essentially. I don't want to use up their data plan for it).

Yeah, consumer reports is blaming the cell phones for poor voice quality, but it really seems to be the phone companies.

In a previous job most of my team worked out of Bulgaria, and I could hear them better over Skype on my iPhone than I could hear my wife on a regular phone call. Headphones helped the sound quality even more, but it really wasn't necessary.

I started playing around with a Lumia 530 on T-Mobile which has HD Voice and the call quality is night and day compared to my Nexus 4. Everyone I've talked to says the calls sound dramatically better and I'm not aware of anyone who has HD Voice capable phones. The noise cancelling seems to be a big thing as most people tell me that they can't tell I'm driving when I have them on speaker phone.

I didn't realize it had HD Voice and chalked it up to Nokia just knowing how to make a decent handset.

This! HD Voice is amazing and honestly I wish I could have a dumb phone that could do Skype calls and HD Voice. Honestly the only reason I like having a smartphone is the better call quality for (some) voice comms.

The Nexus 4 also has HD voice, at least on T-Mobile.

I seriously question your claim and would require some citation. The Nexus 4 call quality is abysmal and the dual microphones to cancel out background noise seem to only amplify it. It's not just my phone because I've had 2 now, I love the phone but it's call quality sucks.

My pet peeve is that speaker phone quality was better on cheap flip-phone vs. what you get a smart phones. This caused me to start using a headset. For home meetings, my cordless phone's speaker phone is better than any cell phone, even though it's using "MagicJack".

The app that I want for my phone is phone.

VoLTE is becoming fairly prevalent now. With the new wideband codecs, quality can be quite good.

The problem is that there is no cross-carrier HD voice or VoLTE. If you call someone on another carrier your call quality will be flushed down the toilet.

These idiots refuse to inter-operate. This is why data calling (Facetime audio, Google Hangouts(?), Skype, Whatsapp, etc) is going to crush the cellular industry. It's going to be fragmented and ugly, but at least the call quality won't suck.

>>These idiots refuse to inter-operate.

Not true. There is tremendous effort in place trying to get IMS roaming/interop working. http://www.gsma.com/newsroom/wp-content/uploads/2013/04/IR.6...

The problem isn't idiots refusing to interoperate, it's that the standards are implemented in subtly different ways between operators.

So if you're on an AT&T or VZW network making calls to a Sprint person, you have 5 dependencies in play:

1) IMS compatible home network w/ HD voice codec support 2) HD Voice compatible home device 3) IMS compatible destination network w/ HD voice codec support 4) Interop agreement between carriers. 5) HD Voice compatible destination device.

Device churn is just as big a hurdle as the non-trivial network compatibility problem.

Exactly. The only realistic way to do it in the short term I think is to have everything fall back to G.711 but they you still end up with multiple codecs which is not idea.

None of those IP voice services interoperate either, it's the same issue just at another layer with a different set of greedy corporations.

True, but it's easy to switch between these upper-level services. It's a pain to change cell providers (in the US).

> It's a pain to change cell providers (in the US).

What!? You can port your number from one carrier to another with ease, for several years now.

Cellular carriers at this point are really just low traffic ISPs anyway.

It seems like if you are calling another network, your network should be able to terminate your HD voice call at the edge, and you would still get at least wired telephone quality.

That's what you get, and it's bad.

It's so bad these days I can't stand talking on the phone to anyone who isn't using data (facetime, etc) or HD Voice. I literally cannot understand what people are saying half the time. And company support phone numbers? The worst. Their callcenters are using terrible voip with overloaded trunks.

It feels like we've spent the last 10 years trying to kill the phone call.

Isn't landline better quality than cell?

Landlines are limited to whatever quality 100 year old degrading copper lines can carry. It's the bare minimum. I had thought for a long time 3G and better had wider bandwidth. I'm not certain though.

I don't think the carriers would want to, a traditional voice call is 'less expensive' than a HD Voice call.

Also you can configure your verizon phone to use voLTE and then google voice supports it, so you can get some voLTE benefits (like using data while on the phone) and voLTE to carriers verizon doesn't yet partner with for voLTE

(VoLTE is branded as HD Voice for many phones.)

Cell phones actually inject "comfort noise" on the receiving end so that you can't detect when the stream is cut off during pauses in the conversation. I would venture that they just keep it on all the time, set above the actual noise in the voice data stream so that you don't hear two different noise levels.

I've been starting to get HD voice calls when I get a hold of someone with a compatible device. The clarity is so improved that we don't end up talking about anything but how good the call sounds.

Call quality on any device I've owned with T-Mobile for the past two years since I switched from AT&T has been great, more carriers need to get off their butts and upgrade to HD Voice.

We have AT&T HD Voice here, it's very impressive if you manage to have two people on new iPhones (6 or better).

So this was from last year it seems. These days there is "HD Voice" on voice calls on t-mobile. Sounds quite good to my, nominal, ears.

but does the average customer care? similar to how Pono may have better audio quality, most people are just fine with a compressed mp3.

Its what works and its just good enough.

> but does the average customer care?

They do, but they don't understand why it's bad. This is 'can you hear me now' and 'what'd you say' happen most of the time

The wideband "hd audio" codec was developed by telecom people in the 70s. The problem with mobile is that the vocoder is trying to cope with a channel having 99% packet loss and latency variance 10x over the mean. The width of the passband is the least of voice's problems.

The solution to mobile voice's problem is for the carriers to invest in a network that isn't ludicrously oversold.

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