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Xiaomi Redmi K40 Gaming Audio review: Loud and artifact-free

Reading Time: 5 min read
68
audio

In spring 2021, Xiaomi released the Redmi K40 Gaming, Redmi’s first gaming smartphone. It’s got a 6.67″ display, OLED flexible straight screen, 5065mAh battery, 67W flash charging, and according to the brand, it’s particularly light and thin. There is even a special K40 Edition Bruce Lee King of Kung Fu, although we tested the standard model.

On the audio side, it has two speakers, three mics, and sound by JBL. Let’s see how it measures up in our rigorous audio test suite.

Audio specifications include:

  • Two speakers at the top and bottom edges of the device, side firing.
  • Three mics
  • Sound by JBL

About DXOMARK Audio tests: For scoring and analysis in our smartphone audio reviews, DXOMARK engineers perform a variety of objective tests and undertake more than 20 hours of perceptual evaluation under controlled lab conditions. This article highlights the most important results of our testing. Note that we evaluate both Playback and Recording using only the device’s built-in hardware and default apps. (For more details about our Playback protocol, click here; for more details about our Recording protocol, click here.)

Test summary


Xiaomi Redmi K40 Gaming
68
audio
71
playback

59
recording

Playback

Pros

Cons

  • The first volume step is too low.
  • There is a lack of low-end extension.

Recording

Pros

Cons

  • Background has a hissy sound.
  • Stereo field is quite narrow.

The Xiaomi Redmi K40 Gaming earned an overall score of 68. Among the devices we’ve tested in our Advanced category, this puts it in good territory, just one point down from the Samsung Galaxy A52 5G, though a few notches further down from the top score in the group, earned by its brand sibling, the Xiaomi Mi 10S, at 80.

Xiaomi Redmi K40 Gaming showed good overall timbre in the movie use case.

In playback testing, the K40 Gaming was somewhat below average in timbre, but had decent scores in the spatial and dynamics attributes, and good scores in volume and artifacts. The device was particularly adept at delivering good overall timbre in the movie use case.

As a recording device, the K40 Gaming fell short of average.  In fact, this was somewhat of a surprise. Its brand sibling, the K40 Pro+, snagged an impressive 70 in recording overall, and an 81 in recording timbre. This Redmi device, on the other hand, produces recordings with uneven timbre and a lot of artifacts.

Sub-scores explained

The DXOMARK Audio overall score of 68 for the Xiaomi Redmi K40 Gaming is derived from its Playback and Recording scores and their respective sub-scores. In this section, we’ll take a closer look at these audio quality sub-scores and explain what they mean for the user.

Playback

Timbre

Xiaomi Redmi K40 Gaming

62

82

Black Shark 4 Pro
Best: Black Shark 4 Pro (82)

Timbre tests measure how well a phone reproduces sound across the audible tonal range and takes into account bass, midrange, treble, tonal balance, and volume dependency.

The Redmi K40 Gaming delivers an adequate performance in timbre, with a tonal balance marked by correct treble and high-end extension in the music use case, though treble was somewhat lacking in some other use cases. The device earned the highest marks when being used for viewing movies, where it delivered more clarity.

Music playback frequency response

The K40 Gaming produces clean midrange, but the high-mids are overly prominent in the movie use case. Despite the lack of low-end extension, bass is correct, especially when the device is held in portrait mode. The tonal balance holds up well at maximum volume, with slightly more bass than at nominal volumes.

Dynamics

Xiaomi Redmi K40 Gaming

69

81

Black Shark 4 Pro
Best: Black Shark 4 Pro (81)

DXOMARK’s dynamics tests measure how well a device reproduces the energy level of a sound source, and how precisely it reproduces bass frequencies.

The Redmi device produces good attack at nominal volume, but it becomes slightly rounded at soft volume. Bass precision is on target, despite the lack of low-end extension, making the envelope of the bass slightly imprecise, especially at soft volume.
Xiaomi Redmi K40 Gaming is the Redmi line’s first gaming phone.

The punch is quite good at nominal volume. The lack of lower frequency content renders it quite feeble at soft volume, however.

Spatial

Xiaomi Redmi K40 Gaming

69

82

Black Shark 4 Pro
Best: Black Shark 4 Pro (82)

The sub-attributes for perceptual spatial tests include localizability, balance, distance, and wideness.

The K40 Gaming earned a respectable score in spatial. Wideness was good, and localizability was also a plus, despite the relative lack of treble to help the ear locate sounds. Voices are well-centered, and the distance rendering is realistic, even if it could be improved with a bit more clarity.

As is the case with many smartphones, the stereo image doesn’t rotate in inverted landscape; that’s especially irksome when watching movies. The K40 Gaming could have had a higher score in this attribute had this flaw been fixed.

Volume

Xiaomi Redmi K40 Gaming

76

79

Black Shark 4 Pro
Best: Black Shark 4 Pro (79)

Volume tests measure both the overall loudness a device is able to reproduce and how smoothly volume increases and decreases based on user input.

The K40 Gaming earned a very good score in the volume attribute, just three points down from the current top score, held by both the Black Shark 4 Pro and the Realme X2 Pro. The loudness is good at maximum volume, but the first volume step is set a little too low to be able to perceive some details. Overall, the volume steps are fairly consistent.

Here are the results of the objective measurements we carried out in our laboratories, using recordings of both hip-hop and classical music played at the maximum user volume step:

Hip-Hop Classical
Xiaomi Redmi K40 Gaming 79.7 dBA 77.4 dBA
Nubia RedMagic 6 Pro 75.9 dBA 72.8 dBA
ZTE Axon 30 Ultra 74.6 dBA 71.3 dBA

Artifacts

Xiaomi Redmi K40 Gaming

86

96

Samsung Galaxy A52 5G
Best: Samsung Galaxy A52 5G (96)

Artifacts tests measure how much source audio is distorted when played back through a device’s speakers. Distortion can occur both because of sound processing in the device and because of the quality of the speakers.

The Redmi K40 Gaming earned an excellent score in this attribute; very few artifacts were observed. A few unwanted signals were present, but they would not be perceivable in daily use.

Recording

Timbre

Xiaomi Redmi K40 Gaming

65

88

Asus Smartphone for Snapdragon Insiders
Best: Asus Smartphone for Snapdragon Insiders (88)

As a recording device, the Xiaomi Redmi K40 Gaming is below average overall. The K40 Gaming’s recordings lack high-end extension, making the sound a bit muffled sometimes. At high volume, the treble can become metallic and sibilant. 

Life video frequency response

The midrange is inconsistent. Numerous resonances make it sound canny and slightly nasal, sometimes even boxy, especially noticeable in the urban selfie video use case. The bass lacks low-end extension, which makes it sound a bit skinny.

Dynamics

Xiaomi Redmi K40 Gaming

60

78

OnePlus 8
Best: OnePlus 8 (78)

The K40 Gaming fares better in recording dynamics, with good signal-to-noise ratio (SNR), which makes recordings clear and intelligible, although in some cases the lack of midrange clarity impairs that intelligibility.

At high volumes, such as in the electronic music concert use case, recordings sound quite compressed, and the envelope is not accurate.

 

Spatial

Xiaomi Redmi K40 Gaming

56

78

Black Shark 4 Pro
Best: Black Shark 4 Pro (78)

Recordings made with the K40 Gaming are not very wide in most cases. The stereo scene is relatively narrow, and the perceived distance seems to be a bit farther than the original source. The noise reduction tends to create a blurriness that impedes the localization of voices.

In the meeting use case, the Redmi device performs better, producing good wideness.

Volume

Xiaomi Redmi K40 Gaming

57

89

Xiaomi Mi 10S
Best: Xiaomi Mi 10S (89)

The K40 Gaming delivers good overall loudness in its recordings, but the feeling of volume can sometimes be lessened by the lack of low-end extension, as in the electronic music concert use case, for example. It performs very well in most other use cases, however, especially in indoor selfie, where it earned an elite score.

Here are our test results, measured in LUFS (Loudness Unit Full Scale). As a reference, we expect loudness levels to be above -24 LUFS for recorded content:

Meeting Life Video Selfie Video Memo
Xiaomi Redmi K40 Gaming -27.7 LUFS -20.2 LUFS -18.9 LUFS -21.7 LUFS
Nubia RedMagic 6 Pro -34.8 LUFS -23.9 LUFS -19.3 LUFS -27.7 LUFS
ZTE Axon 30 Ultra -28.5 LUFS -24 LUFS -26.6 LUFS -20.4 LUFS

Artifacts

Xiaomi Redmi K40 Gaming

65

90

Asus Smartphone for Snapdragon Insiders
Best: Asus Smartphone for Snapdragon Insiders (90)

The K40 Gaming produces quite a few artifacts. It tends to sound compressed and pumping is evident on loud sound sources, such as shouts or loud music.

Xiaomi Redmi K40 Gaming phone does produce quite a few artifacts.

The microphones have a tendency to distort sound sources. In loud situations, such as recording a concert, intermit noises can occur on top of the previously mentioned artifacts. You can check for artifacts yourself in this sample recording:

Background

Xiaomi Redmi K40 Gaming

36

58

Apple iPhone XS Max
Best: Apple iPhone XS Max (58)

The background signal recorded with the K40 Gaming lacks a bit of low-end extension and is resonant in the midrange, making it sound thin and boxy. On top of that, hissing is present on background in most use cases, and this knocked down the score greatly.

Conclusion

Those looking for an adept tool for recording in a variety of situations would be wise to look elsewhere. In playback, the Xiaomi Redmi K40 Gaming will please gamers looking for loud volume, decent spatial attributes, and good performance on dynamics sub-attributes like attack and punch.

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