vivo NEX S Review: Audio
Author:Soomal
Source:eng.soomal.com

Rate:09.88/158

The NEX series is vivo's latest flagships, and its extremely high screen ratio has become its brightest spot. And Soomal, as well as the readers of Soomal, are also very concerned about their audio performance. The Xplay series had been the sound quality banner for vivo, but with the appearance of NEX, Xplay is more and more likely to be cancelled.

NEX S, the NEX Ultimate version, uses the Qualcomm Snapdragon 845 processor, which integrates audio I/O controllers to provide stable and high I/O performance. The DAC used by NEX S is Cirrus Logic CS43199. This DAC is temporarily not found in Cirrus Logic road map. It should be a customized version of vivo. From a few disclosed parameters, it should be very close to the public offering model, CS43198. We guess that the difference is in the package. The CS43198 is an improved version of the CS4399, while the CS4399 is a classic CS4398 upgrade. We infer that CS43199 should be the same design of CS4398. We have paid attention to some statements on the social network, lots are probably confusing CS43199 and CS42LXX. CS42LXX is a low-end CODEC, while CS43199 is a flagship DAC model. The NEX S also uses three Analog Devices SSM6322 op amps. vivo did not explain how the three op amps work together. In order to reduce the area of the fabric, the CS43199 and the three op-amps are packaged together. The official statement is that half of the fabric area is saved compared to XPlay6.

Note that NEX also has a regular version, NEX A, which uses the Qualcomm Snapdragon 710 processor and the AKM AK4376 DAC. It cannot perform better on the sound quality than NEX S, unless vivo screws the NEX S up.

The music player is still old-fashioned style and no major change. It integrates both local and online audio playback. From X21, Deep Field sound effects have been added, but for audiophiles, this is meaningless. Local playback supports mainstream loss and lossless audio formats. NEX S also supports DSD64/128 playback. The compatibility is much better than that of Xplay6. However, switching tracks or fast-forward rewinding operations will cause a buzzing noise, affecting the experience, while playing other types files does not have this problem. The player has been improved intermittently for several years. Operational logic and stability are OK, but the lyric and album cover matching function has not been done well. NEX S is also the same. Hi-Fi is still placed as a system setting to switch and can be licensed for use by third-party app playback.

We start to add USB audio device compatibility test and Bluetooth decode supported test as the popularity of smartphone external device. We choose Musiland MD30 Plus as our audio device, using SuperDSP platform that is compatible with UAC2.0. Another one is Matrix Mini-i Pro 2S, adopting XMOS program. The reason why we choose these two is that they can display the current sampling rate on screen. We will add more devices in the future.

Testing Smartphone iPhone X iPhone 8 Plus Samsung Galaxy Note 8 Samsung Galaxy S8+ Samsung Galaxy S9 Huawei Mate 10 Huawei P20 Pro vivo X20 Plus vivo NEX S vivo X21 OnePlus 5T
UAC 2.0 Devices Auto Switch Sampling Rate Auto Switch Sampling Rate Locked to 48kHz or 192kHz Cannot Work Properly Locked to 48kHz or 192kHz Locked to 96kHz Locked to 96kHz/16bit Locked to 48kHz Locked to 48kHz Locked to 48kHz Locked to 48kHz
Comment higher than or equal to 96kHz will be locked to 192kHz, others are locked to 48 kHz

After turning on OTG support, NEXS can correctly identify the UAC 2.0 device, but the sampling rate will be locked at 48 kHz, that is, any sampling rate will be SRC, which is detrimental to the sound quality. On this issue, we have feedback to vivo on several occasions, but we have not yet resolved it on NEX S.

By convention, we use professional sound cards to record sounds, combining with common analysis, to provide quantitative results. NEX S outputs standard level in Hi-Fi mode, while the output level in normal mode is -7dB.

Testing Item 44.1kHz 44.1kHz @ Hi-Fi Mode 48kHz 48kHz @ Hi-Fi Mode 96kHz @ Hi-Fi Mode Xplay 6 Hi-Fi Mode 44.1kHz
Noise Level, dB -96.4 -96.8 -96.7 -96.4 -117.0 -96.7
Dynamic Range, dB 96.3 96.6 96.7 97.0 117.0 96.4
Total Harmonic Distortion(THD), % 0.0005 0.0005 0.0005 0.0005 0.0003 0.0004
Intermodulation Distortion, % 0.0046 0.0042 0.0043 0.0039 0.0007 0.0042
Stereo Crosstalk, dB -97.0 -97.5 -97.4 -97.3 -111.5 -97.4

The test was successfully completed and no SRC problem was found. The Hi-Fi mode or the normal mode performed very well at 44.1kHz/48kHz. Hi-Res audio test in Hi-Fi mode was passed, while normal mode does not support Hi-Res audio.

Let us show separately the graph of total harmonic distortion in Hi-Fi mode. It can be seen by experienced readers that this is a very good performance. The signal distortion is very small and it is rarely seen in analog signal tests. It also means sound "clean".

In real hearing part, we chose the vivo XE800, Vsonic GR07 carbon nanotube version, Creative Aurvana air, and Audeze LCDi4. The reference model is Xplay6.

Both sound styles are warm trend, and NEX S is warmer.

Treble: Xplay6's treble is slightly brighter, and it has advantages in both transient and dynamic. It can be quite a bit sharper in the performance of some plucked instruments. In the details, Xplay6 is also slightly better, but at high volume, the NEX S's high-frequency control is better and the sound is relatively stable.

Mids: both have very good sound stage, instrumental vocal positioning is very clear, detailed performance is also on par with, are the performance of the current mobile phone first-class performance. There is a slight difference in style, and NEX S sounds softer and more amicable, especially when listening to the voices of mature uncles and sisters.

Bass: The difference between the two bass performance is relatively obvious, NEX S is relatively soft, but the intensity is not bad. Transient of Xplay6 is relatively good, bass income is relatively fast, while in controlling, NEX S is relatively slightly better for sound volume control is more stable at higher volume. In terms of bass details, the NEX S is also slightly better, and really only a slight advantage. It can show the details of the vibration of a large drum slightly more.

If we only talk about details, transients, dynamics, and sound stages, these two smartphones have their advantages, and no one can overwhelm the other. But as for the overall sound, the difference between the two is still relatively easy to distinguish. NEX S is slightly inferior in overall details, but the sound style is softer and tenderer, and the resolution is only relatively weaker compared to Xplay6. In the current mobile phones, it is an absolute tier 1 level. Soft, means not the lacking-strength loose. The sound style of NEX S is basically the old-school-style taste of Cirrus Logic DAC products. The advantages of Xplay6, in fact, is also the advantage of ESS DAC. From the personal preferences of several Soomal editors, we like Cirrus Logic's style more. It can be considered that NEX S has the best sound quality in the current sales of mobile phones, and it is also one of the best sound quality in the development history of mobile phone Hi-Fi products.

If power full-sized headphones and those big appetite earplugs, NEX S still has the problem of obvious lack of output power, which seems to be the biggest bottleneck encountered by mobile phone Hi-Fi. It seems that the more powerful amp can be hardly embedded on the compact mobile phone motherboard, However, if you just power some small earplugs that are easy to push, the performance of NEX S will not be worse than portable DACs around 2000 Yuan (about $300).

From the materials to the actual hearing performance, although not a Hi-Fi high created, but we believe that vivo had paid enough. In the mobile phone Hi-Fi, those followers who have once got into had given up one by one, but vivo is still continuing investment in research and development. We have privately asked why we want to use SiP. The answer is to reduce the layout area and layout costs, so that it can be easily extended to more models. At the very least, the use of a smaller PCB area on the NEX S compared to the Xplay 6 overall shows more possibilities in the future.

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