Verizon iPhone 4: Thoroughly Reviewed
by Brian Klug on February 13, 2011 9:32 AM ESTVoice Quality
The other side of things is voice quality. Unfortunately we're still working on devising some objective call quality tests. On paper, the AT&T iPhone 4 supports wideband and narrowband adaptive multirate (NB-AMR and WB-AMR) voice codecs (vocoders) on UMTS. Remember that on UMTS (3G) voice and data are multiplexed and work at the same time. There's more bandwidth on that link, and as a result UMTS has a higher bitrate voice coder than GSM. That said AMR is variable bitrate (hence the name) and changes depending on link quality. UMTS has more dynamic range compared to GSM and CDMA2000 (EVRC) voice.
On the Verizon iPhone, EVRC is used as the vocoder. That's pretty much standard fare for CDMA2000 voice. The CDMA2000 spec has a number of different of vocoders, the most popular of which are 13k (for 13 kilobits/s), EVRC (which is 8, 4, or 0.8 kilobits/s), and somewhat newer EVRC-B. Way back in the day, it used to be almost trivially easy to change vocoders on Windows Mobile devices, and 13k sounded noticeably better than EVRC, which uses more compression. I've always found EVRC to be noticeably less appealing from an audio perspective than UMTS voice (WB-AMR), but roughly comparable to GSM voice. With EVRC there are audible compression artifacts at the start and end of spoken words, and more blocking and drop-out when 1x signal fades. In comparison, UMTS voice only drops out and degrades substantially right as you're at the bleeding edge of dropping the call entirely. EVRC has less dynamic range than UMTS, so it sounds subjectively louder - the tradeoff is that you lose high and low frequencies. Listening to "ess" sounds in words while on calls is always where the difference is noticeable.
The difference in dynamic range translates to the Verizon iPhone 4 being much louder, the same effect we discussed with the original iPhone 4 between calls on GSM and UMTS.
I set out to show the difference between GSM, UMTS, and CDMA2000 voice by calling the local ASOS weather station. I put together a video with the two iPhones calling the same number and running through the weather report one complete time. Unfortunately, the video camera I have doesn't quite do justice to how audibly different the three calls are, and I lack high quality audio recording equipment. We might follow up with different audio equipment soon, however.
The bigger difference between the two is reliability. Because voice and SMS goes over 1xRTT on Verizon, usually when you can't transact data, calls still work. With the AT&T iPhone 4, when saturation on UMTS happens, you won't be able to call or transact data unless you manually toggle 2G. The result is some built-in robustness for voice on Verizon purely because of that voice/data segregation. In addition, Verizon often puts 1x voice on 800 MHz spectrum and EVDO on 1900 MHz PCS where posisble, so voice coverage tends to work even in places data doesn't necessarily.
In use, the Verizon iPhone 4 will briefly show the "o" symbol for 1xRTT data and then quickly re-acquire EVDO and show "3G." After a call you can see this behavior and the quick re-acquisition of EVDO.
It'd be pure speculation at this point to predict how well Verizon's network will cope with more and more iPhone users. That said, having the data-hungry iPhone on two major carriers definitely will help spread the load as users switch depending on which is better in their market.
Facebook
Twitter
RSS
35 Comments
View All Comments
shakyone - Sunday, February 13, 2011 - link
Wife got the VZ iPhone 6 days ago. I use an Android phone. After one week, I have yet to experience one dropped call of 23, since it arrived, (used Android's call Log). It is as reliable as her VZ Blackberry. The audio is as good too. My brother has an AT&T iPhone 3GS. I don't talk to him that often, but it has dropped calls on me 3 of the last 7 times I called him in the last four months. I don't have much experience with friends that have the AT&T iPhone 4G.MonkeyPaw - Sunday, February 13, 2011 - link
ATT iPhone 3G user here. I have dropped calls all the time. Doesn't matter where I am. Our other phone is a cheap T-mobile phone, and even with a cheap 2 year old flip phone, calls rarely failed. The worst that happened was poor call quality on occasion.Wiggy McShades - Sunday, February 13, 2011 - link
Where do you live? I'm in the Boston area and have never once had a dropped call using an iphone 3g and now an iphone 4. I'm pretty certain my location is why I've had such a great experience with at&t, are you not near a major city? Or is it really just luck that the area I'm in is well covered?JimmiG - Sunday, February 13, 2011 - link
That really is abysmally slow.. not fast enough to watch video at decent quality, for example. I get around 3500kbps down/1400 up in my apartment on the outskirts of town using the HTC Desire and HSDPA, faster near urban centers.I wouldn't call it a smartphone unless you get at least 2Mb, maybe 1.5Mb/s out of it, since slower speeds render many of the features unusable, limiting you to texting and maybe browsing with images turned off.
dagamer34 - Sunday, February 13, 2011 - link
Some signal is better than no signal at all.Shadowself - Sunday, February 13, 2011 - link
This is *absolutely* true. Some signal is better than none.However, as the article mentions, this is very dependent on the individual. One person may almost never experience dropped calls on AT&T due to where and when they use their phone. In such a situation that person may adamantly prefer the AT&T iPhone over the Verison model. Alternately, another person may use their phone -- even in the same city -- in locals and at times where the phone routinely drops calls due to AT&T's network issues. In this case that user would just as adamantly prefer Verison over AT&T.
My wife's personal experience is that the parking lot of her office is a true Verizon dead zone. There is virtually no detectable signal there at all even with very sophisticated equipment and large antennas. You have to move several hundred yards from her parking lot (in almost any direction) for any Verizon phone to work. Verizon has known about this dead spot for over 8 years and has yet to negotiate a new tower in the area (or modify existing towers) to fill that hole. Therefore, for her Verizon is not an option.
It all comes down to what you need and *your" use.
vol7ron - Sunday, February 13, 2011 - link
Oh no. These Verizon vs AT&T flame-wars are almost worse than the Microsoft vs Apple.At least in the later, you had a constant product difference. In service providers its subject to location. And in major cities, I've never had a problem with AT&T except in metros, where they didn't have antennas and Vzn decided to put some up and large venues where you got a lot of units in one tight area at the same time, like large conferences or concerts.
I've had just as much trouble with Verizon black spots as I've had with AT&T. It's all based on where you are and where you travel.
asandok - Sunday, February 13, 2011 - link
In ifixit's teardown they say the wi-fi antenna is what you point out to be the cell antenna. Which is it? It looks like they made a boo boo. Awesome write up though! Love these!Brian Klug - Monday, February 14, 2011 - link
Indeed, the component they pointed to and called the WiFi antenna is the first of two cellular feed lines, and that part has indeed not changed. It's for cellular (and was on the GSM/UMTS iPhone) and not WiFi. Even the FCC correctly labels it as being a feed line for cellular. WiFi has always been at the top in the same place with the same package, though the WiFi antenna did change slightly with the Verizon version.-Brian
Montrey - Sunday, February 13, 2011 - link
Funny you mention how inaudible the vibrate is. I had my Verizon iPhone on vibrate during a physics test Friday, it rang in the pocket of my jeans and my professor heard it 20 feet away and threatened to kick me out if I didn't turn off my phone. Maybe he just has superhuman hearing, I thought it was pretty quiet, especially compared to the droid eris it just replaced.