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Sennheiser CX True Wireless Headphones Review

Tested using Methodology v1.5
Reviewed Aug 11, 2021 at 09:45 am
Sennheiser CX True Wireless Picture
6.6
Neutral Sound
7.5
Commute/Travel
8.1
Sports/Fitness
6.8
Office
5.5
Wireless Gaming
5.3
Wired Gaming
6.3
Phone Calls
Type In-ear
Enclosure Closed-Back
Wireless Truly Wireless
Noise Cancelling No
Mic Yes
Transducer Dynamic

The Sennheiser CX True Wireless are the next-generation version of the Sennheiser CX 400BT True Wireless. These in-ears are well-built, very portable, and have a stable, breathable fit. Their bass-heavy default sound profile may not suit all listeners, but thankfully you can adjust this via their in-app EQ. On the downside, they're relatively bulky by the standards of truly wireless in-ears, which could lead to some discomfort during longer listening sessions. They also lack an ANC feature and do a poor job of blocking out bass-range ambient noise like the rumble of bus or plane engines.

Our Verdict

6.6 Neutral Sound

The Sennheiser CX True Wireless are okay for neutral sound. Out-of-the-box, they have a somewhat warm, bass-heavy sound profile that adds thump and rumble to EDM and hip-hop tracks but can muddy some vocals and lead instrumentals. Their underemphasized treble response can also veil and muffle higher notes. Thankfully, their companion app features a graphic EQ that allows you to tweak their audio reproduction to your liking.

Pros
  • Full-featured companion app.
Cons
  • Compact soundstage.
7.5 Commute/Travel

The Sennheiser CX True Wireless are good for commuting and traveling. They're compact and sturdy, which makes them a good option for on-the-go use. Their six-hour-plus battery life is decent, and their charging case supplies enough power for roughly two additional charges. They also have very low Bluetooth audio latency on mobile devices, though this can vary in the real world. Unfortunately, they struggle to block out bass-range ambient noise, like the low rumble of bus or plane engines.

Pros
  • Great build quality.
  • Full-featured companion app.
Cons
  • Struggle to block out bass-range ambient noise.
8.1 Sports/Fitness

The Sennheiser CX True Wireless are a great option for sports and fitness. They have a fairly stable fit, though they can start to loosen if you move your head around too vigorously. They're also highly breathable, so you shouldn't sweat more than usual while wearing them. Their control scheme is also fairly fully-featured, allowing you to make a wide range of adjustments without requiring you to pull out your phone and ruin your rhythm. In addition, they feel very well-built with an IPX4 rating for water resistance, but we don't currently test for that.

Pros
  • Great build quality.
  • Stable, breathable fit.
  • Comprehensive control scheme.
Cons
  • Bulky design protrudes from the ear.
6.8 Office

The Sennheiser CX True Wireless are alright for office use. They do an excellent job of blocking out ambient chatter and high-pitched background noise, like the hum of an AC unit. They also leak very little noise, so you can listen to content at a high volume without worrying about annoying nearby coworkers. They should also last most of your workday on a single charge, though this can vary in the real world. On the downside, they don't support multi-device pairing, so you can't stream music from your phone while remaining connected to your computer.

Pros
  • Full-featured companion app.
  • Minimal audio leakage.
  • Excellent isolation against ambient chatter and high-pitched background noise.
Cons
  • Poor mic recording quality.
  • Struggle to block out bass-range ambient noise.
  • No multi-device pairing.
5.5 Wireless Gaming

The Sennheiser CX True Wireless aren't recommended for wireless gaming. They're fully compatible with Bluetooth-enabled PCs, but their latency is likely to be too high for gaming. They're also incompatible with Xbox and PlayStation consoles.

5.3 Wired Gaming

The Sennheiser CX True Wireless are Bluetooth-only headphones that can't be used on a wired connection.

6.3 Phone Calls

The Sennheiser CX True Wireless are passable for making phone calls. The integrated microphone makes recorded speech sound muffled and thin, but it does a satisfactory job of isolating your voice from background noise, so people on the other end of the line should still understand you even if you make a call in a moderately noisy environment. While these headphones do an excellent job of blocking out background chatter and high-pitched ambient noise, they really struggle with low-end background noise, so you may have a hard time hearing what's being said if you take a call on a bus or a train.

Pros
  • Decent microphone noise handling capability.
  • Excellent isolation against ambient chatter and high-pitched background noise.
Cons
  • Poor mic recording quality.
  • Struggle to block out bass-range ambient noise.
  • 6.6 Neutral Sound
  • 7.5 Commute/Travel
  • 8.1 Sports/Fitness
  • 6.8 Office
  • 5.5 Wireless Gaming
  • 5.3 Wired Gaming
  • 6.3 Phone Calls
  1. Updated Oct 27, 2021: Retested 'Dock Charging'.
  2. Updated Aug 11, 2021: Review published.
  3. Updated Aug 09, 2021: Early access published.

Test Results

perceptual testing image
Design
Design
Style

The Sennheiser CX True Wireless are basic-looking in-ears. Their squared-off shape is very similar to the Sennheiser CX 400BT True Wireless, though the newer model features matte-finish touch panels with black embossed logos instead of the older model's glossy touch panels with silver manufacturer logos.

6.5
Design
Comfort
Weight 0.03 lbs
Clamping Force
0 lbs

The Sennheiser CX True Wireless are fairly comfortable. They feel lightweight and don't enter your ear canals very deeply. That said, their outer casing protrudes somewhat far from the sides of your head, and they're relatively bulky by the standards of truly wireless headphones.

6.8
Design
Controls
OS Compatibility
Not OS specific
Ease Of Use Good
Feedback Good
Call/Music Control Yes
Volume Control Yes
Microphone Control No
Channel Mixing
No
Noise Cancelling Control No
Talk-Through
No
Additional Controls Voice Assistant

These headphones have an alright control scheme. It's fairly easy to use for the most part, and you can remap their control scheme through the Sennheiser Smart Control companion app. Tapping on either bud once pauses and plays media or answers and ends phone calls. A double tap on either bud rejects incoming calls, while a triple tap on either bud enables your phone's voice assistant. You can skip to a previous track by double-tapping the left bud. A double tap on the right buds skips to the next track. You can increase or decrease media volume by holding the right or left bud, respectively. The in-ears give you a voice prompt for successful Bluetooth pairing. They also provide an audible chime for each input, and there are different audio cues for increasing or decreasing media volume. Unfortunately, it's easy to accidentally brush their touch panels with your finger when adjusting their fit.

9.2
Design
Breathability
Avg.Temp.Difference 0.8 ยฐC

Like most in-ears such as the Cambridge Audio Melomania 1+ True Wireless, these headphones are very breathable. They don't really trap heat inside your ears. Consequently, you shouldn't sweat more than usual if you wear them while working out.

9.3
Design
Portability
L 1.4" (3.5 cm)
W 1.2" (3.1 cm)
H 1.2" (3.0 cm)
Volume 1.96 inยณ (32.20 cmยณ)
Transmitter Required No

The Sennheiser CX True Wireless are remarkably portable. The buds are very compact and can easily slip into a pocket or a purse. Their case is also very small and should easily fit in most pockets or bags.

7.5
Design
Case
Type Hard case
L 1.3" (3.3 cm)
W 2.3" (5.9 cm)
H 1.7" (4.2 cm)
Volume 5.01 inยณ (82.10 cmยณ)

The Sennheiser CX True Wireless' charging case is good. It's made of hard plastic, isn't too large, and features magnets inside to keep the buds from falling out of their cradles.

8.0
Design
Build Quality

The Sennheiser CX True Wireless feel impressively well-built. They're made entirely from matte-finish hard plastic, which feels sturdy and does a good job resisting fingerprints. Unfortunately, their swappable ear tips feel like they could tear easily. Sennheiser lists an IPX4 rating for water resistance on their website, but we don't currently test for that.

7.5
Design
Stability

The Sennheiser CX True Wireless are stable in-ears. They don't move around too much with low-intensity movements, though vigorous shakes of the head can loosen their fit.

Design
Headshots 1
Design
Headshots 2
Design
Top
Design
In The Box

  • Sennheiser CX True Wireless headphones
  • 4x Ear tip options
  • Charging case
  • USB-C to USB-A charging cable
  • Safety instruction manual and other guides

Sound
Sound
Sound Profile
Bass Amount
2.49 dB
Treble Amount
-3.27 dB

The Sennheiser CX True Wireless have a warm, bass-heavy sound profile. This should emphasize the thump and rumble of EDM and hip-hop music but can slightly muddy vocals and lead instruments. Their treble range is also somewhat underemphasized, which can veil the upper harmonics of vocals and lead instruments. Thankfully, their companion app features a graphic EQ and audio presets that let you adjust their audio reproduction to your liking.

9.2
Sound
Frequency Response Consistency
Avg. Std. Deviation
0.17 dB

These headphones have fantastic frequency response consistency. Once you achieve a proper fit with the included ear tips, bass and treble response should be perceived similarly every time you use them.

Sound
Raw Frequency Response
7.1
Sound
Bass Accuracy
Std. Err.
4.38 dB
Low-Frequency Extension
10 Hz
Low-Bass
2.5 dB
Mid-Bass
4.9 dB
High-Bass
6 dB

The Sennheiser CX True Wireless have decent bass accuracy. The entire range is overemphasized, yielding additional thump and rumble and giving some instruments and vocals extra punch. However, the overemphasized high-bass range can make some mixes boomy and muddy.

8.0
Sound
Mid Accuracy
Std. Err.
2.64 dB
Low-Mid
4.06 dB
Mid-Mid
0.01 dB
High-Mid
0.18 dB

These headphones have great mid accuracy. The overemphasis from the bass range carries over into the low-mids, which can muddy vocals and lead instruments. Thankfully, the mid-mid and high-mid ranges are well-balanced and accurate, resulting in clear and present vocals and lead instruments.

6.6
Sound
Treble Accuracy
Std. Err.
5.02 dB
Mid-Treble
-0.06 dB
Low-Treble
-5.35 dB
High-Treble
-2.62 dB

These headphones have okay treble response. The low and mid-treble ranges are underemphasized, which can veil vocals and lead instruments and dull sibilants like S and T sounds.

7.3
Sound
Peaks/Dips
Peaks
1.58 dB
Dips
1.68 dB

The Sennheiser CX True Wireless have decent peaks and dips performance. A bump in the high-bass range carries over into the low-mids, which gives a muddy quality to some mixes. A dip in the mid-mids can nudge some vocals toward the back of the mix, while a bump in the high-mid range can make them slightly boxy. A larger dip throughout the low-treble range veils vocals and lead instruments. The adjacent rise in the mid-treble range can give a piercing quality to sibilants, like S and T sounds.

9.3
Sound
Imaging
Weighted Group Delay
0.13
Weighted Phase Mismatch
2.14
Weighted Amplitude Mismatch
0.28
Weighted Frequency Mismatch
1.11

These headphones have superb stereo imaging performance. The weighted group delay falls mostly beneath the audibility threshold, resulting in a tight bass and transparent treble response. The L/R drivers are also very well-matched in phase, amplitude, and frequency response, so objects like voices or footsteps should be accurately placed within the stereo image. That said, these results are only valid for our test unit, and yours may perform differently.

0.9
Sound
Passive Soundstage
PRTF Accuracy (Std. Dev.)
N/A
PRTF Size (Avg.)
N/A
PRTF Distance
N/A
Openness
3.5
Acoustic Space Excitation
0.5

Like most closed-back in-ears, the Sennheiser CX True Wireless have a terrible passive soundstage. Creating an out-of-head soundstage relies on interaction with the outer ear, which in-ears like these bypass entirely. Consequently, sound is perceived as coming from inside your head rather than all around you.

0
Sound
Virtual Soundstage
Head Modeling
No
Speaker Modeling
No
Room Ambience
No
Head Tracking
No
Virtual Surround
No
7.7
Sound
Weighted Harmonic Distortion
WHD @ 90
0.325
WHD @ 100
0.122

The Sennheiser CX True Wireless have a good weighted harmonic distortion performance. Most frequencies fall within good limits, so audio reproduction should be clean and pure.

Sound
Test Settings
Firmware
1.6.8
Power
On
Connection
Bluetooth 5.0
Codec
aptX, 16-bit, 48kHz
EQ
Neutral
ANC
No ANC
Tip/Pad
Silicone (small)
Microphone
Integrated

These are the settings used to test these headphones. Our results are only valid when listening using these settings.

Isolation
6.4
Isolation
Noise Isolation
Isolation Audio
Overall Attenuation
-18.46 dB
Bass
-5.22 dB
Mid
-18.11 dB
Treble
-33.29 dB

The Sennheiser CX True Wireless have passable noise isolation capability. Unfortunately, unlike the Sennheiser CX Plus True Wireless, they don't have active noise cancelling and rely on their passive noise isolation capabilities to block out ambient noise. That said, they do a bad job of isolating you from bass-range ambient noise, like the rumble of bus and plane engines, but perform very well when it comes to isolating you from mid and treble-range background noise, like chatter from people nearby or the high-pitched hum of an AC unit.

9.6
Isolation
Leakage
Leakage Audio
Overall Leakage @ 1ft
23.61 dB

The Sennheiser CX True Wireless have a superb leakage performance. You should be able to listen to content at a high volume without worrying about disturbing people nearby, even in quiet environments.

Microphone
Microphone
Microphone Style
Integrated
Yes
In-Line
No
Boom
No
Detachable Boom
No
5.4
Microphone
Recording Quality
Recorded Speech
LFE
334.17 Hz
FR Std. Dev.
4 dB
HFE
2,248 Hz
Weighted THD
10.521
Gain
20.22 dB

The integrated mic's recording quality is poor. Recorded speech sounds muffled, thin, and lacking in detail.

7.1
Microphone
Noise Handling
SpNR
35.42 dB
Noise Gate
Always On
Speech + Pink Noise Handling
7.5
Speech + Pink Noise Audio Sample
Speech + Subway Noise Handling
6.5
Speech + Subway Noise Audio Sample

The integrated mic delivers decent noise handling capability. People on the other end of the line should understand you fairly clearly if you're calling from a moderately noisy environment, like a busy street. That said, people may have a harder time hearing you if you call from a louder setting, like a moving subway car.

Active Features
7.2
Active Features
Battery
Battery Type
Rechargable
Continuous Battery Life
6.6 hrs
Additional Charges
2.0
Total Battery Life
19.8 hrs
Charge Time
1.1 hrs
Power-Saving Feature
Auto-Off Timer
Audio While Charging
Yes
Passive Playback
No
Charging Port USB-C

These headphones have satisfactory battery performance. They provide over six and a half hours of playback time on a single charge, which does fall short of the manufacturer's advertised claim of nine hours. Their case should provide roughly two additional charges, which should be sufficient for a couple of days of use. That said, battery life can vary in the real world depending on your usage habits. They're also advertised to supply up to an hour's worth of playback on 15 minutes of charging, but we don't currently test for that. Unlike the older Sennheiser CX 400BT True Wireless, they have an auto-off timer to help conserve the charge when not in use, which you can adjust in their companion app.

7.5
Active Features
App Support
App Name Sennheiser Smart Control
iOS Yes
Android Yes
macOS No
Windows No
Equalizer
Graphic + Presets
ANC Control
No
Mic Control No
Room Effects
No
Playback Control
No
Button Mapping Yes
Surround Support
No

The Sennheiser Smart Control app is good. You can customize the headphones' audio reproduction via a graphic EQ or audio presets, which includes the 'Bass Boost' preset for a bit of added thump and rumble, though we don't currently test the headphones with this preset active. You can also re-map their control scheme, turn off audio cues for touch inputs, or check their battery level.

Connectivity
7.0
Connectivity
Bluetooth
Bluetooth Version
5.2
Multi-Device Pairing
No
NFC Pairing
No
Line Of Sight Range
226.38 ft (69.00 m)
PC Latency (SBC)
377 ms
PC Latency (aptX)
321 ms
PC Latency (aptX HD)
N/A
PC Latency (aptX-LL)
N/A
iOS Latency
36 ms
Android Latency
23 ms

The Sennheiser CX have decent Bluetooth connectivity. They don't support NFC or multi-device pairing, so you can't stream music from your phone while remaining connected to your computer. Their latency on Bluetooth-enabled PCs is high when using SBC or aptX codecs, but they perform very well in this regard when connected to iOS and Android devices, so audio and visuals shouldn't appear out of sync. Of course, it's worth noting that latency can vary drastically depending on the specific device and app that you're using.

0
Connectivity
Non-Bluetooth Wireless
Non-BT Line Of Sight Range
N/A
Non-BT Latency
N/A
0
Connectivity
Wired
Analog Audio
No
USB Audio
No
Detachable No
Length N/A
Connection
No Wired Option
Analog/USB Audio Latency
N/A

The Sennheiser CX are Bluetooth-only headphones and can't be used on a wired connection. They come with a USB-C to USB-A cable for charging their case.

Connectivity
PC Compatibility
Analog
No
Wired USB
No
Non-BT Wireless
No

The Sennheiser CX are fully compatible with Bluetooth-enabled PCs. They don't support any other kind of wireless connectivity other than Bluetooth, and their latency is likely to be too high for gaming.

Connectivity
PlayStation Compatibility
PS4 Analog
No
PS4 Wired USB
No
PS4 Non-BT Wireless
No
PS5 Analog
No
PS5 Wired USB
No
PS5 Non-BT Wireless
No
Connectivity
Xbox Compatibility
Xbox One Analog
No
Xbox One Wired USB
No
Xbox One Non-BT Wireless
No
Xbox Series X|S Analog
No
Xbox Series X|S Wired USB
No
Xbox Series X|S Non-BT Wireless
No
2.2
Connectivity
Base/Dock
Type
Charging Case
USB Input
No
Line In
No
Line Out
No
Optical Input
No
RCA Input
No
Dock Charging
Yes
Power Supply
USB-C

Update 10/27/2021: We incorrectly reported that 'Dock Charging' wasn't supported. However, this was a mistake, and we have changed 'Dock Charging' to 'Yes' and updated our review.

The Sennheiser CX come with a charging case that supplies about two additional charges. You can recharge the case itself via USB-C, but it doesn't support wireless charging.

Differences Between Sizes And Variants

The Sennheiser CX True Wireless are available in two color variants: 'Black' and 'White'. We tested the 'Black' variant, and you can see its label here. That said, we expect the other color variant to perform similarly overall.

Let us know in the discussions if you come across another variant.

Compared To Other Headphones

The Sennheiser CX are well-rounded truly wireless in-ears. Compared to their predecessor, the Sennheiser CX 400BT True Wireless, these in-ears have an auto-off timer to help conserve battery life but perform very similarly otherwise.

If you're looking for alternatives, take a look at our list of recommendations for the best earbuds and in-ear headphones, the best true wireless earbuds, and the best wireless Bluetooth earbuds.

Sennheiser CX 400BT True Wireless

The Sennheiser CX True Wireless are better than the Sennheiser CX 400BT True Wireless for most uses, though the two pairs of headphones are similar overall. The CX have longer battery life and an auto-off timer to help conserve power when not in use. Their companion app also has a slightly wider range of configuration options. Conversely, the CX 400BT offer better microphone recording quality.

Sennheiser MOMENTUM True Wireless 2

The Sennheiser CX True Wireless are better than the Sennheiser MOMENTUM True Wireless 2. The CX have a slightly less dark default sound profile, offer better microphone noise handing capability, have more options in their companion app, and last longer on a single charge. They also have an auto-off timer to help conserve charge when not in use. While the MOMENTUM do have an ANC system, they perform similarly to the CX when blocking out ambient noise. That said, the MOMENTUM also have a fuller-featured control scheme, a sturdier charging case, and superior microphone recording quality.

Sony WF-1000XM3 Truly Wireless

The Sony WF-1000XM3 Truly Wireless are better than the Sennheiser CX True Wireless. The Sony are more comfortable, have a better-balanced out-of-the-box sound profile, block out more ambient noise thanks to their ANC system, and support NFC pairing. Their companion app also has a wider range of features. Meanwhile, the Sennheiser have a more stable fit, leak less audio, and feature on-board volume controls.

Jabra Elite 75t Truly Wireless

The Jabra Elite 75t Truly Wireless are slightly better for most use cases than the Sennheiser CX True Wireless. The Jabra have a more comprehensive control scheme, feel comfier in the ear, offer superior mic recording performance, are compatible with a more feature-rich companion app, and support multi-device pairing. Meanwhile, the Sennheiser have better mic noise handling performance.

Sennheiser CX Plus True Wireless

The Sennheiser CX Plus True Wireless are the upgraded variant of the Sennheiser CX True Wireless and offer a slightly better overall performance. While both are fairly comfortable and well-built, the Plus have a more neutral default sound profile, which some users may prefer. They also have active noise cancelling, and while they outperform the base model, they only do an okay job of blocking out noise. The Plus also have a significantly better battery performance, and they support aptX Adaptive codec.

Apple AirPods Pro Truly Wireless

The Apple AirPods Pro Truly Wireless are better than the Sennheiser CX True Wireless. The Apple in-ears have a more comfortable, stable fit, a better-balanced out-of-the-box sound profile, and block out a greater degree of ambient noise thanks to their ANC system. They also have a spatial audio feature on compatible devices, though we don't currently test for that. Meanwhile, the Sennheiser leak less audio, deliver better overall mic performance, have a longer single-charge battery life, and support a wider range of sound customization features through their companion app.

Samsung Galaxy Buds+ Truly Wireless

The Samsung Galaxy Buds+ Truly Wireless are better than the Sennheiser CX True Wireless. The Samsung have a comfier and more stable fit, come with a smaller charging case, have a better-balanced out-of-the-box sound profile, and deliver better overall mic performance. They also last more than twice as long on a single charge, though this can vary in the real world, and it's worth noting that they case only supplies roughly one extra charge. Meanwhile, instead of the Samsung's in-app audio presets, the Sennheiser's companion app grants you access to a graphic EQ. The Sennheiser also feel better-built and leak slightly less audio.

Sony WF-1000XM4 Truly Wireless

The Sony WF-1000XM4 Truly Wireless are a little bit better than the Sennheiser CX True Wireless. The Sony are comfier, blcok out more ambient noise thanks to their ANC feature, and have a longer battery life as well as a more feature-dense companion app. Conversely, the Sennheiser leak less audio and have on-board volume controls.

Samsung Galaxy Buds Pro Truly Wireless

The Samsung Galaxy Buds Pro Truly Wireless are slightly better than the Sennheiser CX True Wireless. The Samsung are more comfortable, have a better-balanced sound profile, and block out more ambient noise thanks to their ANC feature. They also have superior mic recording quality, though the Sennheiser's integrated mic does a better job of isolating speech from background noise. The Sennheiser also have a longer battery life, a more feature-packed companion app, superior build quality, and lower levels of audio leakage.

Beats Studio Buds True Wireless

The Sennheiser CX True Wireless are better than the Beats Studio Buds True Wireless. The Sennheiser feature on-board volume controls, feel better-built, have a more stable fit, have a longer battery life along with an auto-off timer, and a companion app with a graphic EQ. In addition, while the Beats do have an ANC feature, they do a worse job of filtering out ambient noise than the Sennheiser. However, the Beats do charge faster, have superior microphone recording quality, and feel more comfortable to wear.

Beats Solo Pro Wireless

The Beats Solo Pro Wireless and Sennheiser CX True Wireless are different types of headphones that suit different purposes. The Beats are wireless on-ears with a much longer continuous battery life. They're also equipped with an ANC system that helps them block out a good amount of ambient noise. Meanwhile the Sennheiser are truly wireless in-ears that are significantly more portable and have a more breathable fit. They also leak less audio and have a more consistent sound delivery.

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