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.
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.
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.
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.
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.
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.
The Sennheiser CX True Wireless are Bluetooth-only headphones that can't be used on a wired connection.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
These are the settings used to test these headphones. Our results are only valid when listening using these settings.
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.
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.
The integrated mic's recording quality is poor. Recorded speech sounds muffled, thin, and lacking in detail.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The Sennheiser CX True Wireless are better than the Beats Studio Buds True Wireless. The Sennheiser feature onboard 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.
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.
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.
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.
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.
The Sony WF-C500 Truly Wireless are better for most purposes than the Sennheiser CX True Wireless. The Sony have a much more comfortable fit, better noise isolation, and a more neutral default sound profile that some may prefer. They also have longer continuous battery life and a significantly better mic recording quality. However, the Sennheiser are better-built, have a more stable fit, and their Βluetooth latency with iOS and Android devices is lower.
The Apple AirPods Pro Truly Wireless are better than the Sennheiser CX True Wireless. The Apple in-ears have a more comfortable 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.
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.
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.
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.