We subjected the Xiaomi Mix Fold 2 to our rigorous SBMARK audio test suite to measure its performance both when recording sound using its built-in microphones, and when playing audio through its speakers.
In this review, we’ll analyze how it performed in a variety of tests and several common use cases.
Overview
Key audio specs include:
- Three speakers (two on the underside when unfolded, one under the front screen when folded)
- No audio jack output
- Dolby Atmos technology
Reproduction
Pros
- Sharp attack and good punch across all volume levels
- It tends to sound better at higher volumes
Against
- Disappointing spatial performance for a foldable
- More artifacts than expected
- Disappointing tonal performance
Registration
Pros
- Good dynamic performance
- Mostly free from unwanted audio artifacts
Against
- No audio zoom capability.
- Tonal balance could be better in some apps
With a SBMARK audio score of 121, the Xiaomi Mix Fold 2 performed decent overall in our tests compared to the smartphone market as a whole. However, the results started to look a little less impressive when you consider the Mix Fold 2’s large size in its unfolded state and its hefty price tag. Overall, Xiaomi’s latest foldable is somewhat of a missed opportunity in terms of the physical implementation of speakers and microphones, as well as audio tuning.
As a playback device, the Mix Fold 2 worked best when listening to music, but it was also a decent option for gaming and watching movies, thanks to sharp attack and good punch across the board of volume. Overall playback quality was pretty poor for a device at the higher end of the Ultra-Premium price range. The same could be said for the recording, but on the bright side, most of the audio recordings remained intelligible in windy conditions and were fairly free of artifacts.
Trial summary
Learn about SBMARK audio tests: For scoring and analysis in our smartphone audio reviews, SBMARK engineers perform a series of objective tests and undertake more than 20 hours of perceptual evaluation under controlled laboratory conditions.
(For more details on our playback protocol, click here; for more details on our recording protocol, click here.)
The following section compiles the key elements of our extensive testing and analysis performed in the SBMARK laboratories. Detailed performance evaluations in the form of reports are available upon request. Do not hesitate to contact us.
How the audio playback score is composed
SBMARK engineers test playback through smartphone speakers, the performance of which is evaluated in our labs and under real-life conditions, using apps and preset settings.
When using the Mix Fold 2 as a playback device, it delivered average tonal performance in our tests. Tonal balance was disappointing overall, with a focus on the top end but also a lack of brightness in the upper treble. At the same time, the bass was insufficient, despite the artificial boost. Dynamics were pretty good overall, thanks to very crisp attack across all volume levels, decent bass accuracy, and good punch.
The Xiaomi scored decently in the space category, but given the device’s large size when unfolded, our testers expected much more. When held in portrait orientation, the Mix Fold 2 offered no stereo audio. The width of the rendered soundstage was decent in landscape orientation, but again the results seemed less impressive considering the device’s large size. The localizability of individual sound sources in the scene was quite good, but voices sounded too far away most of the time.
Our audio experts found the maximum volume to be average and the minimum volume too low for good intelligibility of quiet content. However, the volume steps were consistent from the lowest level to the highest. We encountered a number of unwanted audio artifacts during our testing, including compression and distortion at all volume levels. With the device unfolded, it was also virtually impossible not to cover the left and right speakers with your hands.
Hear about the playback performance of the smartphone tested in this comparison with some of its competitors:
Recordings of smartphones playing some of our songs at 60 LAeq in an anechoic environment via 2 microphones in AB configuration, at 30 cm
Here’s how the Xiaomi Mix Fold 2 fares in playback use cases compared to its competitors:
Playback of use case scores
The Timbre score represents how well a phone reproduces sound across the audible tonal range and takes into account bass, mids, treble, tonal balance, and volume dependency. It is the most important attribute for reproduction.
Frequency response of music reproduction
A 1/12-octave frequency response graph, which measures the loudness of each frequency emitted by your smartphone as it reproduces a pure sine wave in an anechoic environment.
The Dynamics Score measures the accuracy of changes in the energy level of sound sources, such as how accurately a bass note or impact sound of drums is played.
Secondary attributes for spatial testing include pinpointing the location of a specific sound, its positional balance, distance, and amplitude.
The volume score represents the overall volume of a smartphone and how smoothly the volume increases and decreases based on user input.
Here are some sound pressure levels (SPL) measured while playing our sample recordings of hip-hop and classical music at maximum volume:
hip-hop | Classic | |
Xiaomi Mix Fold 2 | 72.2 dBA | 67.9 dBA |
Samsung Galaxy Z Fold4 | 71.1 dBA | 67.3 dBA |
Apple iPhone 14 Pro Max | 74 dBA | 71.1 dBA |
The following graph shows the gradual changes in volume from minimum to maximum. We expect these changes to be consistent across the range, so that all volume steps match user expectations:
Music volume consistency
This line graph shows the relative loudness of the playback versus the user selected volume step, measured at several volume steps with correlated pink noise in an anechoic box recorded 0.20 meter on axis.
The artifact score measures the extent to which the sound is affected by various types of distortion. The higher the score, the less noticeable sound disturbances are. Distortion can occur due to the sound processing in the device and the quality of the speakers.
Playback Total Harmonic Distortion (maximum volume)
This graph shows total harmonic distortion and noise over the audible frequency range.
It represents the distortion and noise of the device playing our test signal (0 dB Fs, Sweep Sine in an anechoic box at 40cm) at the device’s maximum volume.
How the score of the audio recording is composed
SBMARK engineers test recording by evaluating recorded files on reference audio equipment. These recordings are made in our laboratories and under real-life conditions, using apps and default settings.
When recording, the Xiaomi delivered decent tonal performance overall, but our experts found the tonal balance lacked top-end range and brightness when recording with the main and selfie cameras. When recording at high SPLs, for example, concerts, the tonal balance was subtly rendered, with a significant lack of bass and bass extension. In terms of dynamics, the device offered an average signal-to-noise ratio. The envelope was quite accurate but overall sounded slightly flat.
Sound scene recording breadth was good with the main camera, but noticeably smaller with the selfie camera and memo app. Distance rendering was realistic and locateability was good across all use cases, resulting in overall average spatial performance. Volume performance was good in all use cases, and in our recording tests, the Mix Fold 2 was virtually free of unwanted artifacts aside from some bass distortion and pumping at high SPLs. The rendering of the background was quite natural.
Here’s how the Xiaomi Mix Fold 2 fares in recording use cases compared to its competitors:
Use case scoring
The Timbre Score represents how well a phone captures sounds across the audible tonal range and takes into account bass, mids, treble, and tonal balance. It is the most important attribute for registration.
Video frequency response of life
A 1/12-octave frequency response graph, which measures the loudness of each frequency captured by your smartphone while recording a pure sine wave in an anechoic environment.
The Dynamics Score measures the accuracy of changes in the energy level of sound sources, such as how accurately plosives in a voice (p, t, k, for example) are reproduced. The score also considers the signal-to-noise ratio (SNR), such as how loud the lead voice is compared to the background noise.
Secondary attributes for spatial testing include locating a specific sound’s location, positional balance, distance, and amplitude on recorded audio files.
Directness of registration
Smartphone directivity graph while recording test signals using the camera app, with the main camera. It represents the acoustic energy (in dB) on the angle of incidence of the sound source. (Normalized to 0° angle, in front of the device.)
The loudness score represents how loud audio is normalized on recorded files and how well the device handles noisy environments, such as electronic concerts, while recording.
Here are the sound levels recorded in the audio and video files, measured in LUFS (Loudness Unit Full Scale); for reference, we expect volume levels to be above -24 LUFS for recorded content:
Encounter | Videos life | Selfie videos | Memorandum | |
Xiaomi Mix Fold 2 | -25.3 LUFS | -22.8 LUFS | -19.7 LUFS | -20.8 LUFS |
Samsung Galaxy Z Fold4 | -25.8 LUFS | -21.6 LUFS | -22.7 LUFS | -21 LUFS |
Apple iPhone 14 Pro Max | -26 LUFS | -22.9 LUFS | -19.2 LUFS | -19.6 LUFS |
The Artifacts score measures the extent to which recorded sounds are affected by various types of distortions. The higher the score, the less noticeable sound disturbances are. Distortions can occur due to in-device sound processing and microphone quality, as well as user handling, such as how the phone is held.
In this audio comparison, you can hear how this smartphone handles wind noise compared to its competitors:
matrix(3) {
[“Xiaomi Mix Fold 2”]=> string(64) “resources/Xiaomi/MixFold2/XiaomiMIXFold2_MicrophoneArtifacts.m4a”
[“Samsung Galaxy Z Fold4”]=> string(69) “resources/Xiaomi/MixFold2/SamsungGalaxyZFold4_MicrophoneArtifacts.m4a”
[“Apple iPhone 14 Pro Max”]=> string(69) “resources/Xiaomi/MixFold2/AppleiPhone14ProMax_MicrophoneArtifacts.m4a” }
Recordings of a voice sample with slight background noise, facing a 5 m/s turbulent wind
Background evaluates how smoothly various sounds around a voice blend into the video recording file. For example, when recording a speech at an event, the background shouldn’t interfere with the main vocal, but should provide context of your surroundings.
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