With the sweet-spot of affordable true wireless earbuds now firmly established around the £100-£120 (sub-$150) mark, Sennheiser’s new CX True Wireless enter the fray, having dropped their price significantly from the outgoing September 2020 model to make the cut.
Looking at the spec-sheet, it is no small feat either; the company's proprietary TrueResponse transducer (which is designed and manufactured at the firm’s HQ in Germany and found in more premium models in the brand's line-up) still features, as does Bluetooth 5.2 with aptX support, a host of EQ optimisations via the Sennheiser Smart Control app, and even a neat slider feature labelled Sidetone, to control the level of audible feedback of your own voice during phone calls.
There’s no active noise cancellation on board (and no clunky ‘BT’ suffix), but with an IPX4 splash- and sweat-proof rating, there’s enough here to make us more than a little intrigued.
Build
Refreshingly, the CX’s small charging case stands upright with its flip-top case facing skywards, so that you can open the box and grab the buds even while they’re charging. It’s a little thicker than some of the most svelte cases on the market, but it is still light and feels relatively durable. Inside, the buds are nicely housed with magnets to keep them secure, but they aren’t particularly small or ergonomically shaped. The housings are almost square, weighing 6g apiece (as a guide, the two buds together weigh the same as an AAA battery), and the neck of the buds is on the long side, meaning that even if you downsize to the smallest of the four pairs of eartips provided, those with smaller ears may struggle to achieve a decent or comfortable fit here.
The multi-function sensor on each earpiece is also very easy to cover (and thus deploy) while trying to fit them, but once a decent seal is achieved, the functions are customisable and work very reliably indeed. From the box, play or pause is a single tap of either earpiece, two taps on the left bud skips back a track, two on the right skips forward and a long-press of either earpiece increases (right) or decreases (left) the volume. Three taps of the right bud summons Siri on our iPhone.
Accepting and ending calls is intuitive and works well, aided by the two beamforming mics in each earpiece. It’s an intuitive solution and a useful one, especially when you consider that many competing buds at the price (and beyond it) have failed to offer on-ear volume control.
Under the bonnet, Sennheiser’s TrueResponse Transducer 7mm dynamic driver takes centre stage. Despite the slightly bulky design of the earpieces (and thus, the slightly thicker case) those who favour a minimalist or brutalist aesthetic in their listening gear will find much to enjoy in the squared-off buds, both bearing Sennheiser’s angular but simple S-in-a-rectangle logo.
Bluetooth 5.2 with AAC and aptX
Battery life 27 hours (9 hours from the buds)
Dimensions 59 x 33.8 x 42.3mm (earbuds and charging case)
Weight 6g per earpiece (49g with the case)
Finishes x2 (black and white)
Water resistance IPX4
Nine hours of playtime, 27 in total when added to available juice in the case, completes an interesting proposition – not class-leading, but competitive nonetheless.
Sadly, when we first pair the buds (after updating the firmware), both pair but only one earpiece produces sound. Both units work for play/pause and volume adjustment, but when we disconnect and re-pair, it is only the other bud that produces playback. After 10 minutes or so of trying we achieve sound from both, but it’s a strange experience considering Sennheiser’s commendable history in the true wireless headphones sphere.
Features
Perhaps it’s best that we list the things you aren’t getting first. There’s no active noise cancellation onboard, no transparency feature, and no auto-off wearer detection when you remove them. However, what you are getting is the very slick and intuitive experience offered by the Sennheiser Smart Control app. Here, you can connect further devices, which are then saved in the ‘Connections’ tab. It’s not quite as effortless as multi-device pairing, but once added, switching music sources is a case of toggling one off and the other on – simpler than going in through the Bluetooth menu every time you want to connect from your phone to your laptop.
You can also play with two distinct and detailed methods of EQ adjustment here (one standard three-band, one a curved line you simply move and shape with your finger), then save them as presets, or select from Sennheiser’s own curated profiles including Podcast, Movie or Bass Boost. Although for the majority of our testing we keep the EQ levels at neutral, it’s worth experimenting with these as they may help tailor the sound a little to your particular taste.
Despite our initial issues when pairing, it’s worth noting that connectivity in the CX is technically a level above the older Sennheiser CX 400BT, which launched as a more affordable successor to the company's Award-winning Momentum True Wireless 2 last September, with no IP rating, lesser stamina and Bluetooth 5.1. Here, you’re getting IPX4 splash proofing plus Bluetooth 5.2 compatibility with SBC, AAC and aptX codec support for higher-resolution listening. Throughout testing, the slick and enjoyable Sennheiser Smart Control app never crashed.
Sound
Kicking off our listening with Bamboleo by the Gypsy Kings, each initial duelling guitar lick is delivered first to our left ear, then our right, with ample space and a good deal more separation than we usually experience through in-ear designs. The hand claps also feel three-dimensional through the treble, if a tad harsher than ideal.
Our playlist continues to Gypsy by Shakira, but here we note that the strummed guitars and vocals through the lower midrange are more textured and exciting through our benchmark product for this test, the Cambridge Audio Melomania 1 Plus. Dynamically, the CX feel a little subdued in comparison, lacking an extra ounce of detail through the rise and fall of each note.
The bass weight plays no small part in the issue. It is expansive but a little bloated and not particularly agile, so that the overall presentation comes off somewhat lacklustre in terms of dynamic build.
Switching to Don’t Stop Believin’ by Journey, we note that although there’s a good deal of space around each instrument in the soundstage, the treble guitar riff is slightly hard in isolation, which only adds to a confusing mix timing-wise. Each musical strand seems to have a habit of wandering off a little, leaving us unable to tap our feet in time to the rhythm – even when listening to this classic marching rock track.
Verdict
The Sennheiser CX joins a duo of celebrated five-star siblings to make up Sennheiser’s true wireless line-up; excellent company to keep – provided you don’t fall short sonically. The CX buds weigh the same as the CX 400 BT, but although they will still suit some ears, a few members of the team found the units bulky and quite uncomfortable to wear, even after a few hours of testing.
The seven extra hours of battery life and new IP-rating are welcome additions over their affordable predecessors – and the in-app features are nothing short of excellent for the level – but when it comes to the sound, we find ourselves scratching our heads to explain the treble harshness, timing issues and slightly flabby bass.
SCORES
- Build 3
- Features 4
- Sound 3
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Read our Sennheiser CX 400BT review
