We put the OnePlus Open through our rigorous SBMARK Audio test suite to measure its performance in both recording sound using the built-in microphones and playing audio through its speakers.
In this review, we’ll break down how it performed in a variety of tests and several common use cases.
Overview
Key audio specifications include:
- Three speakers (top left, top right, bottom right, when open)
- No jack audio output
Playback
Pros
- Very pleasant and warm tone
- Stereo in portrait orientation (when open)
- Excellent artifact performance
Against
- Very limited upper treble and treble extension
- The minimum volume is too low
- Dynamic performance is hindered by compression
- Apart from portrait stereophony, unremarkable spatial performance
Registration
Pros
- Good tonal balance, consistent across all use cases
- Good signal-to-noise ratio
- Good spatial performance
- Excellent audio zoom performance
Against
- Midrange can lack clarity, treble lacks top-end extension
- Fights high sound pressure levels
With an overall score of 135, the OnePlus Open performed well in the SBMARK Audio tests. Thanks to an additional speaker, it is one of the very few foldable phones that offer stereo playback in portrait orientation when opened, making better use of its design and large size and providing better immersion than most competitors.
In our tests, the OnePlus performed consistently well in all use cases, thanks to a very pleasant timbre in both playback and recording. Our testers appreciated the device’s effective audio zoom feature, but also noted some flaws such as a lack of high-end extension, sometimes excessive dynamic processing, and compression in both playback and recording. According to measurements, neither the integrated speakers nor the microphones offer a full frequency range, which is unusual for a device of this class. However, that didn’t stop the OnePlus from delivering satisfying timbre and solid performance in our tests.
Test summary
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 brings together key elements of our comprehensive testing and analysis performed in 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, whose performance is evaluated in our labs and in real-life conditions, using apps and default settings.
In playback, the OnePlus Open offered a pleasant timbre with a smooth tonal balance. The midrange was particularly warm and satisfying, but the lack of upper treble resulted in a certain dullness when listening to music. The bass sounded quite strong and round, but lacked extension in the low end. Dynamic performance was decent overall, but significantly hampered by high-volume compression. Attack seemed crisp and precise when listening to music or watching movies, but appeared slightly weak when gaming. Its performance was less satisfactory even at low and maximum volumes. As for bass performance, it offers good support, but the accuracy of the envelope was compromised by the compression, which also had a negative impact on the punch.
Thanks to a third speaker at the top left of the device, OnePlus Open is one of the rare and few foldables that offer stereo in vertical orientation as well as horizontal. However, the spatial performance still leaves some room for improvement. For starters, in our tests, the third speaker was very quiet, meaning that neither the balance nor the amplitude were actually good in portrait orientation, despite stereophony. The results in landscape orientation were also not particularly impressive. The stereo image wasn’t too wide, and while localizability was fine, it wasn’t always easy to locate individual sound sources. Distance performance was quite good, but voices could sound slightly further away than expected.
The distribution of volume levels was quite consistent and the maximum volume setting was quite high, but our experts found that the minimum volume level was extremely low and therefore difficult to use. Artifact performance was very good however, with only some compression evident at both nominal and maximum volumes, which was generally not problematic for the listening experience. Additionally, the device’s built-in speakers were virtually impossible to occlude.
Listen to the playback performance of the tested smartphone in this comparison with some of its competitors:
Recordings of smartphones playing some of our music tracks at 60 LAeq in an anechoic environment using 2 microphones in AB configuration, at 30 cm
Here’s how the OnePlus Open performs in playback use cases compared to its competitors:
Playing use case scores
The Timbre score represents the quality with which a phone reproduces sound across the entire audible tonal range and takes into account bass, midrange, treble, tonal balance and volume dependence. It is the most important attribute for reproduction.
Frequency response of music playback
A 1/12 octave frequency response graph, measuring the loudness of each frequency output by the smartphone when playing 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 the sound of a drum impact is reproduced.
Secondary attributes of spatial tests include identifying 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 (SPLs) measured when playing our sample recordings of hip-hop and classical music at maximum volume:
| Hip Hop | Classic | |
| OnePlus open | 75 dBA | 73.5 dBA |
| Samsung Galaxy Z Fold5 | 72.8 dBA | 69.4 dBA |
| Apple iPhone 15 Pro Max | 75.1 dBA | 72.3 dBA |
The following graph shows the gradual changes in volume going from minimum to maximum. We expect these changes to be consistent across the range, so that all volume increases match user expectations:
Music volume consistency
This line graph shows the relative volume of playback versus the user-selected volume increment, measured at different volume increments with correlated pink noise in an anechoic box recorded on-axis at 0.20 meters.
The Artifacts score measures the extent to which the sound is affected by various types of distortion. The higher the score, the less noticeable the sound disturbances will be. Distortions may occur due to the sound processing in the device and the quality of the speakers.
Total harmonic distortion during playback (maximum volume)
This graph shows total harmonic distortion and noise in 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 40 cm) 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 in real-life conditions, using apps and default settings.
When used as a recording device, OnePlus provided good tonal balance in all use cases. With the main and front cameras, the treble was correct but would have benefited from some additional high-end extension. It seemed clearer with the memo app. The midrange was satisfying and natural in all use cases, and while bass performance was good, it lacked low-end extension and depth. Thanks to a very effective noise reduction algorithm, the signal-to-noise ratio was good when recording with the main and front cameras. Attack was generally sharp and precise, but at high sound pressure levels, such as when recording loud concerts, the compression resulted in a lack of clarity.
The breadth of the sound stage and the localizability of individual sound sources proved to be very good when recording with the main camera. With the front camera the range was more limited, but the localizability remained good. Furthermore, distance rendering was realistic on all recording apps. Recording volume was adequate with the main and front cameras, but slightly weaker with the Memo app. Recordings made with the OnePlus were mostly free of artifacts, except for some compression at high sound pressure levels. Background rendering was also excellent and free of noticeable artifacts.
Here’s how OnePlus Open performs in recording use cases compared to its competitors:
Recording use case scores
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, measuring the loudness of each frequency captured by the 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 a voice’s plosives (p, tek, for example) are reproduced. The score also considers the signal-to-noise ratio (SNR), such as how loud the main voice is compared to the background noise.
Secondary attributes for spatial testing include identifying the location of a specific sound, its positional balance, distance, and amplitude on recorded audio files.
Directivity of registration
Graph of smartphone directivity while recording test signals using the camera app, with the main camera. It represents the acoustic energy (in dB) compared to the angle of incidence of the sound source. (Normalized to the 0° angle, in front of the device.)
The loudness score represents how well the audio on recorded files is normalized and how well the device handles noisy environments, such as electronic concerts, during 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 about life | Selfie videos | Memorandum | |
| OnePlus open | -26.8 LUFS | -21 LUFS | -19.2 LUFS | -19.1 LUFS |
| Samsung Galaxy Z Fold5 | -25.8 LUFS | -22.1 LUFS | -21 LUFS | -21.1 LUFS |
| Apple iPhone 15 Pro Max | -24.9 LUFS | -22.1 LUFS | -20.5 LUFS | -19.2 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 the sound disturbances will be. Distortions may occur due to the sound processing in the device and the quality of the microphones, 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) {
[“OnePlus Open”]=> string(62) “resources/OnePlus/OpenV2.2/OnePlusOpen_MicrophoneArtifacts.m4a”
[“Samsung Galaxy Z Fold5”]=> string(70) “resources/OnePlus/OpenV2.2/SamsungGalaxyZFold5_MicrophoneArtifacts.m4a”
[“Apple iPhone 15 Pro Max”]=> string(70) “resources/OnePlus/OpenV2.2/AppleiPhone15ProMax_MicrophoneArtifacts.m4a” }
Recordings of a speech sample with light background noise, exposed to a turbulent wind of 5 m/s
Background evaluates how naturally the various sounds around a voice blend together in the video recording file. For example, when recording a speech at an event, the background should not interfere with the main voice, but should provide context to the surrounding environment.
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