vivo Xplay 6 Review: Call Quality


Xplay 6 is the latest vivo flagship smartphone. It is an upgraded version of Xplay 5s with larger internal storage, RAM, audio, and an extra camera. Of course, we are still concerning about the call quality.

Although Qualcomm provided a more advanced processor, Snapdragon 821, Xplay 6 still adopts the Qualcomm Snapdragon 820 processor, just the same with Xplay 5s. Snapdragon 821 has a higher frequency, a higher camera supporting, but the same X12 LTE modem, which supports all wireless network provided by China's mobile telecom carrier. Aqstic, named by Qualcomm, is the audio CODEC responsible for all audio I/O. A phone call requires not just the processor, DSP and CODEC chip, but also microphone, speaker and the internal driver. Most Chinese brand Android smartphones are adopting Qualcomm or MTK's solution, although the solutions are similar, manufacturers are using different microphones, circuit designs, and even tendency, so the call quality of different smartphones is also quite different.

Let's go back to Xplay 6. It adopts dual microphone for sampling, just like most android smartphones, the voice solution and noise cancellation algorithm are provided by Qualcomm. You can switch off dual-microphone noise cancellation if you are worrying about the call quality under extreme noisy scenes. Xplay 6 supports China Mobile VoLTE. Users in Beijing can send a message to open this function and get 200 minutes' free calls. By convention,

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, and 10086 [VoLTE], which is China Mobile customer service hotline. Then use professional sound card and microphone for recording and analysis.

Testing Item Xplay 6 OPPO R9s iPhone 7 Plus Moto Z One Plus 3 Huawei P9 Xplay 5s
Output Level of Earpiece,dB -10.56 -11.5 -8.06 -18.43 -10.46 -7.59 -9.55

Xplay6's earpiece output volume is average, similar to Samsung Galaxy S7 Edge and One Plus 3. You can see from the recording frequency response graph that the output sampling rate under VoLTE gains from 4kHz to 8kHz, leading a more detailed, richer and brighter voice, especially female voice. However, another reason, has nothing to do with Xplay 6, is China Mobile improved the poor hotline voice quality.

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 vivo Xplay 6 OPPO R9s MOTO Z iPhone 7 One Plus 3 Xplay 5S Huawei P9
Face Up,dB 78.1 78.7 74.1 79.2 76.8 78.7 74.8
Face Down,dB 78.3 77.0 75.2 78.6 77.3 80.4 74.7
In Camera Bag,dB 70.0 69.4 69.8 72.6 72.3 73.4 67.4

Xplay 6's loud speaker has a slight lower volume than Xplay 5s, and a similar sound tendency. However, it sounds thinner and dryer than iPhone 7 Plus, Google Nexus 6P, or even an elder Xplay 3s at high volume. The majority smartphones' loud speaker we tested are similar to Xplay 6, high volume but not that good quality.

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[GSM Hand Holding] Noisy Crowd Background Music Pink Noise Roadside Voice
Total Noise Level Reduction,dB[Higher is Better] 34.1 21.8 36.2 43.1 23.4
SNR Improvement,dB[Higher is Better] 28.4 17.4 30.9 34.2 18.8
SNRI-to-NPLR difference,dB[-4 to 3] -1.5 1.5 -3.1 -3.6 1.8
Testing Item[VoLTE Hand Holding] Noisy Crowd Background Music Pink Noise Roadside Voice
Total Noise Level Reduction,dB[Higher is Better] 41.3 32.1 43.9 48.4 34.3
SNR Improvement,dB[Higher is Better] 34.7 28.5 37.9 40.7 23.3
SNRI-to-NPLR difference,dB[-4 to 3] -3.5 1.2 -4.7 -5.2 1.2
Testing Item[Hand-Free Mode] Noisy Crowd Background Music Pink Noise Roadside Voice
Total Noise Level Reduction,dB[Higher is Better] 38.2 28.1 42.3 45.1 25.5
SNR Improvement,dB[Higher is Better] 29.2 21.3 31.8 33.4 17.3
SNRI-to-NPLR difference,dB[-4 to 3] -7.3 -0.8 -8.5 -8.8 0.4
  • 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.

Xplay 6's overall noise cancellation ability is similar to that of Xplay 5s. When dual-microphone noise reduction switched on, the recording level will lower than raw voice signal, and voice signal will be lost at hand-free mode. If you call under noisy scene, or use hand-free mode often, we recommend you to switch off dual-microphone noise reduction to gain the call volume.

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