Sony Xperia XZ Premium Review: Call Quality
Author:Soomal
Source:eng.soomal.com

Rate:10.00/10

Xperia XZ Premium is the latest Sony flagship smartphone, Except the Sony brand, the 4K solution HDR display screen and latest Exmor RS IMX400 also attracts lots attention. Calls are still the fundamental function of a phone, will it be good? Now, let's have a look at it.

Why delayed? Because our Xperia XZ Premium met some problem on earpiece speaker, that when hand-holding calling, the earpiece would crack lot that cannot be function normally, we must send it to repair. After repairing, this Xperia XZ Premium got right, no cracks again.

Our Sony XZP comes with the Qualcomm SD835 processor, supports dual SIM card. Sony designed a special SIM card slot, that users can pull the tray out with just their fingernails. If you change a SIM card or MicroSD card, it would restart automatically. The SIM1 tray is using a single tray, and using a LED light to detect whether it is open or closed, when the light leaks, this smartphone may regard this is changing inserted card, then restart. So, we strongly recommend you keep an eye on this tray when changing your SIM or MicroSD card. The call, contractor, SMS interface is just like what native Android is. As usual, we place this cell phone indoor with normal signal, and set the call voice volume to maximum, then call 10010 [GSM], which is China Unicom customer service hotline, and 10086 [VoLTE], which is China Mobile customer service hotline. And we use WeChat, the most popular tool in china, as VoIP. Then use professional sound card and microphone for recording and analysis.

Earpiece Speaker Test

We place this cell phone indoor with normal signal, and set the call voice volume to maximum, then call 10010 [GSM], which is China Unicom customer service hotline. Then use professional sound card and microphone for recording and analysis.

Testing Item Xperia XZ Premium OnePlus 5 Nubia Z17 HTC U11 Galaxy S8+ iPhone 7 Plus
Output Level of Earpiece,dB -11.85 -9.54 -9.89 -10.18 -10.2/-9.98 -8.06

The earpiece speaker has a relative low volume, and sounds a little thin in vocal. It is interesting that it is a little lauder [about -10.8dB] before repaired.

Loud Speaker Test

Speaker test was undertaken indoors with ambient noise level at 40dB or less, we turn up the ringtone volume to its maximum, and then use a sound level meter to measure sound level at the distance of one meter from the phone.

Testing Item Xperia XZ Premium OnePlus 5 Nubia Z17 HTC U11 Galaxy S8+ iPhone 7 Plus
Face Up,dB 69.4 79.9 75.8 75.6 73.4 78.9
Face Down,dB 71.5 77.4 75.7 74.8 73.7 79.8
In Camera Bag,dB 64.8 75.5 74.7 75.6 69.1 73.3

Although Xperia XZP has stereo speakers, its volume is lower than the mainstream, such as Samsung Galaxy S8, HTC U11, or Nubia Z17.

Noise Reduction Test

We place this phone indoors with ambient noise level at 32db or less, in the middle of the room, we use a human-like structure "handholding" the phone to send voice signal, and put surround speakers in a certain distance playing 5 kinds of simulating ambient noise at 6db SNR. Then we standardize the recording from this end, and run a specific program comparing this recording with raw speech recording and noise-speech mixed recording to get noise reduction level, SNR improvement and SNRI-to-NPLR difference quantitative result.

Testing Item[Hand Holding] Noisy Crowd Background Music Pink Noise Roadside Voice
Total Noise Level Reduction,dB[Higher is Better] 37.0 36.8 37.4 35.6 39.8
SNR Improvement,dB[Higher is Better] 29.3 31.8 30.7 29.4 31.2
SNRI-to-NPLR difference,dB[-4 to 3] -1.6 0.6 -2.0 -1.9 0.3
Testing Item[Hand Free] Noisy Crowd Background Music Pink Noise Roadside Voice
Total Noise Level Reduction,dB[Higher is Better] 16.4 18.6 28.5 27.7 15.7
SNR Improvement,dB[Higher is Better] 6.6 16.3 19.4 18.9 11.0
SNRI-to-NPLR difference,dB[-4 to 3] -5.2 0.0 -5.3 -3.1 0.7
Testing Item[VoIP] Noisy Crowd Background Music Pink Noise Roadside Voice
Total Noise Level Reduction,dB[Higher is Better] 30.5 25.0 38.0 37.8 29.2
SNR Improvement,dB[Higher is Better] 13.1 15.1 18.8 17.6 20.2
SNRI-to-NPLR difference,dB[-4 to 3] -0.5 -0.9 -1.5 -0.6 0.1
  • Total Noise Level Reduction, TNLR: Total Noise Level Reduction illustrates the reduction of ambient noise level. The average level is above 5dB. Theoretically, higher TNLR would be better, but an over high result may be caused by severe attenuation of voice signal, or interruption caused by poor phone signal or noise reduction algorithm flaw.
    Signal-to-Noise Ratio Improvement, SNRI: capability of an NS method to enhance the speech component of a noisy speech signal from an additive background noise. SNR improves after noise reduction by comparing noise-reduced and raw voice signal. Generally, the improvement is over 4dB.
    SNRI-to-NPLR difference, DSN: the signal level difference between raw and noise-reduced. Noise reduction process would attenuate voice signal level, cell phones would gain signal to ensure the call quality. Theoretically, it would be best that signal level remain the same before and after noise reduction. A standard signal level peak is -2.5dB. If the signal was gained too high, overflow would happen, and that means frequent crackle, too low, voice signal strength would not be enough, and that means the sound would be too low, and the other end would not hear clearly.
    The result is just a test reference under similiar circumstances or conditions, third-party websites or official technical data cannot be used for comparison.

Sony Xperia XZ Premium has an excellent hand-holding noise reduction performance, for it can filter almost all music or voice ambient noise which are hard to be distinguished. In hand-free mode, it is not that excellent as it performs in hand-holding mode, for losing some voice signal in noisy circumstance. However, its VoIP performance is not as good as the Qualcomm Snapdragon 835 equipped smartphones, but still reliable.

In summary, Sony Xperia XZ Premium has a fair call performance. It has an excellent noise reduction in hand-holding mode, the only shortage of it is the relatively low laud speaker volume.

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