TWS true wireless earphones - under $150
4.5 STARS - The Sennheiser CX is great value for money, with outstanding noise reduction and call quality, app support with lots of customization, and great sound - although perhaps not as sparkly as the previous CX 400BT.
Sennheiser CX specs:
Bluetooth 5.2 with AptX and AAC codec
IPX4 waterproof (splash proof)
9 hours listening on a full charge
Charging case can charge earpieces fully 2 times
Comes with 4 rubber ear tips, USB-C cable, English manual
$130 - check price on Amazon US, Amazon Germany or other Amazon stores
Below this Sennheiser CX review, you will find comparisons between the Sennheiser CX vs Sennheiser CX 400BT, Cambridge Audio Melomania 1+, Lypertek PurePlay Z3, and Soundcore Life P3.
Update April 2025: Due to increased competition, I've changed the overall ranking for these earbuds from 5 to 4.5 stars.
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Design, comfort and battery life
It's easy to see the Sennheiser CX is the follow-up to the previously released Sennheiser CX 400BT. The differences are minimal. The new CX has a black logo on top of the case instead of a silver one, and the case misses the obsolete button you could re-pair the original CX 400BT with. The single LED light that indicates the remaining case battery has been moved from the back to the front: more convenient.
Sennheiser CX 400BT (left), the new CX on the right
The outsides of the earbuds now have a dark-grey touch panel instead of a shiny black one. Again, the logo is a bit more hidden - black instead of silver. The new CX distributes the subtle microphone holes over both its earbuds instead of only the right one, and this new placement could just help to provide the new CX its IPX4 splash-proof rating. In contrast, the older one doesn't have a waterproof indication. What splash-proof is exactly? Well, it survived a light rain during the test period.
So what do you get for the $130 price tag of the Sennheiser CX? Well, a sturdy square case and above-average sized earbuds that fill up your ears. They feel big when you're wearing them the first times but eventually become comfortable. They fit snugly in stay secure in medium-sized ears, and as they fill up your ears, they reduce and block out many sounds around you - the passive noise reduction performs up to ANC noise-cancelling levels even!
Battery life is great: the buds reach up to 9 hours of playtime on a single charge. With the square (well-built but scratch-sensitive) case, you can recharge them two times fully before it needs new power itself.
Connectivity and controls
The touch panels on the Sennheiser CX don't provide the same brilliant feedback as on the 400BT, but the control scheme and sensitivity is still rock-solid.
Tap L or R to play/ pause music
Double-tap R to skip a song
Double-tap L to return a track
Hold R to increase the volume
Hold L to decrease volume
Triple-tap L or R to activate the voice assistant
Hold both earbuds for 3 seconds to enter pairing mode and pair another device.
When you're paired with multiple devices, you can switch between them from the app. This is a bit cumbersome, and as with almost all wireless earbuds, the CX doesn't automatically switch between devices, for instance, from your laptop to your phone when you receive a phone call.
If the control scheme isn't to your liking, you can change controls completely via the free Sennheiser app.
Connectivity on the CX is solid, with a strong Bluetooth connection up to 9-10 meters away from your device. The earbuds take some time to pair and connect, but you can always listen to one earbud when you're charging the other - and return to stereo when you take the charged bud out again. They don't automatically pause music when you take one out.
Calling and watching movies
Unlike the previous CX 400BT, synchronization between audio and video is spot on, on iPhone and Android. Watching videos with them is a breeze. There is a noticeable delay in sound effects when you're playing games, and the Sennheiser doesn't have a low-latency mode to reduce this.
Happily, the Sennheiser CX is top-notch when it comes to calls. Except for when you're walking and facing strong wind directly, the call clarity is fantastic. Your voice is loud, clear, and naturally full. It seems to pass through more nuances in your voice than most other wireless earphones do. Meanwhile, noises around you are reduced well. Chatter and accelerating scooters can be heard and identified as such for the person you're talking to, but these sounds stay in the background - your voice is louder and clearer than anything else.
Performance in video calls like Microsoft Teams or Zoom meetings is also great. Although there's a minimal hiss underneath your voice when background noise is detected, your voice again sounds loud, clear, and full.
As a finishing touch, the app lets you choose how much you want to hear your voice when you're taking a phone call or video call. Splendid.
App support of Sennheiser CX
The Sennheiser CX enjoys support from Sennheisers free Smart Control app for Android and iPhone. It doesn't require an account or ask too many permissions, can update the firmware of the earbuds (this takes up to a ridiculous FOURTY minutes), and offers various other functions as well:
Change the earbuds controls
Choose the auto-shutdown time of the earbuds
Swap between different devices you've connected to
Choose how much you want to hear your voice when taking a call; choose between 0%, 50%, and 100% - neat!
Choose between prompt sounds, tones, voice, or both
Change the sound yourself by dragging down a line or a 3-band-equalizer
Save your customized sound equalizer
Select one of three standard sound presets or your customized equalizers.
Tap the earbuds image to change controls
Editing the sound isn't very convenient
You can also change sound via a tri-band equalizer
While it's great you can customize the earbuds' sound, dragging down a line to alter the sound still feels finicky. The app is too unclear in this area: you can't just tap on 'Neutral' to select another sound signature; it will completely overhaul and save the sound because you tapped somewhere on the screen to change the line. Instead, you need to tap the bottom right to find the presets of Sennheiser and your own saved signatures - it feels a bit too hidden. Altering the sound by dragging the bass, mids, or highs up and down is more convenient, but on this page, the presets button is gone.
The standard signatures are Neutral (the out-of-the-box-sound which is, as you'll read, far but neutral), Podcast (emphasizes voices), and Bass (for lovers of rumbling bass).
Save and select presets
Sidetones decide how clear you'll hear yourself in calls - brilliant!
Firmware updates take… long
Even though the app interface could be easier, it has a lot of useful functions to add to the CX.
Also read: The best wireless earbuds under $100
Sound quality of Sennheiser CX: More bass
When it comes to sound, the CX builds upon the foundation of the CX 400BT. Sennheiser did change it a bit, and it's questionable whether that's for the better.
Most noticeable is that Sennheiser puts even more emphasis on the bass on the CX. There's a Bass Boost sticker on the packaging, and it's there for a reason. The mid-bass has a slightly stronger thump but feels more cleaned up at the same time. It's a bit tighter, with more controlled strikes that have more impact on their own. Not the quickest though. The sub-bass seemed to get to same treatment: it's fuller yet more precise than before.
On the Sennheiser CX 400BT, the bass is a companion to its open and warm sound. The CX keeps the boosted lower-mids and the warm sound that comes with it, but this time, it seems to resolve around the bass. No matter if you're listening on high or low volumes - the bass is a bit dominant. Especially on background listening volume, it could use a bit more subtlety sometimes.
Upper-mids on the CX are more focused, meaning they are now more dedicated to pushing female and higher-pitched male vocals forward. They sound full and clear, fluent but with plenty of nuances. The CX rolls off the highs before they have a chance to get bright or hash - this is one smooth ride.
Unfortunately, Sennheiser did reduce the center-mids and upper-mids other than vocals a bit. That's where the CX loses a bit of sparkle over the CX 400BT. The predecessor gives some more room to guitars, piano, cymbals, and other higher notes surrounding the vocals, which provides the music with more air and creates the intimate soundstage of the 400BT. The new CX lacks the same sense of space in the music overall and in between instruments. It's harder to place instruments precisely around you.
While we're talking about subtle changes here, the difference is noticeable for critical listeners. When you consider yourself one, it puts you up for a choice: the CX 400BT if you seek space and detail; the Sennheiser CX if you embrace a big bass.
The CX may not be as lively as its predecessor, but it's a great choice for bass lovers.
Sennheiser CX comparisons
Sennheiser CX 1 vs Sennheiser CX 400BT
While this review is one big comparison between these two models, here's a summary of the now $80 Sennheiser CX 400BT versus the newer $130 Sennheiser CX. The latter has IPX4 waterproof rating, two hours more battery life on a single charge, and better video playback. It has more nifty app options, like (slowly) switching between paired devices and making you hear yourself during calls. The CX sound is more dedicated to bass and higher vocals; they are more prominent and tighter than on the 400 BT. The cheaper older model has slightly more focus on mid-tones, giving the sound more space and more detail in acoustic instruments. While both sound fantastic, the older CX 400BT sounds a bit more… unique.
Sennheiser CX vs Cambridge Audio Melomania 1+
The Melomania 1+ is the sequel to the Melomania, and it walked the same line as Sennheiser did. Meaning: the newer model has tighter and slightly more emphasized lows and a little less pronunciation of mid-tones. Compared to the CX, though, the Melomania 1+ sounds more natural. The 1+ has a much gentler mid-bass and displays guitars and other acoustic instruments with increased naturality and texture. Vocals sound more raw and lifelike on the 1+, opposed to a smoother approach on the Sennheiser, which also boasts more bass energy and sounds fuller. Battery life on both is 9 hours; the Cambridge Audio has a better waterproof level and a more pocketable case; the Sennheiser wins on comfort and call quality.
Sennheiser CX vs Lypertek PurePlay Z3
Choose your favorite features: the Lypertek PurePlay Z3 has a shower-proof IPX7 rating, and its case can recharge the earbuds 7 times fully. The Sennheiser CX has a smaller case and noticeable better call clarity. Both earbuds have up to 9 hours of playtime and a warm sound with powerful bass. The PurePlay Z3 extends upper-mids and highs more, adding extra clarity and liveliness to the music - the CX smooths them out. The Sennheiser boosts lower-mids further and sounds fuller. The Lypertek has slightly more separation between frequencies and instruments instead.
Lypertek PurePlay Z3 review ($80-100)
Sennheiser CX vs Soundcore Life P3
With app support, Active Noise Cancelling, and a Transparency Mode so you can hear your surroundings when listening to music, the $80 Soundcore Life P3 is more feature-packed than the Sennheiser. But not all of it remains: the CX's passive noise reduction is about as strong as Soundcore's ANC! Call quality on the Sennheiser is even better, and you'll get 2 hours more battery life per charge, too. Both have a bass-heavy, warm sound with plenty of clarity in vocals and comfortable, quickly rolled-off highs. The Soundcore requires more equalizer-customization than the Sennheiser to open up the sound, but it's very easy to do so with the Acoustic EQ-setting. The Sennheiser is more precise in the lows, with better-controlled mid-bass, and has more fullness and air. Is it worth $50 extra? That's up to you.
Soundcore Life P3 review ($80)
Verdict
The Sennheiser CX is a solid successor to the Sennheiser CX 400BT, with the same fantastic call quality, yet better waterproof rating, video playback, and battery life. It sounds a little bassier and less spacious than the predecessor, but that doesn't take away that this is a great pair of wireless earphones.
Update April 2025: Due to increased competition, I've changed the score from 5 to 4.5 stars.
4.5 stars - Great
Buy Sennheiser CX:
I received the Sennheiser CX from the Dutch distributor to test and review. My reviews are 100% independent and non-commercial. I test and review all audio products equally honest - read about it here.
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