Sennheiser CX True Wireless Review

When it comes to the true wireless game, there isn’t a brand as dominant as Sennheiser. While they bring you some of the best studio and audiophile headphones around, Sennheiser also supplies some great Bluetooth products, like the over-ear Momentum 3 and the Momentum 2 true wireless. About a year ago, Sennheiser released the CX400BT, which was a slightly more inexpensive follow-up to the Momentum 2. It comes with its unique features, like interchangeable controls. Now, Sennheiser has released a new version of that model, simply titled the CX True Wireless. Let’s see what Sennheiser has done to improve this line further.

Sennheiser contents

What You Get

  • CX True Wireless Earbuds
  • Silicone ear adapter sets (XS, S, M, L)
  • Charging Case
  • USB-C Cable
  • Quick Guide & Safety Guide

Sennheiser in hands

Look and Feel

Just taking a single glance at the CX true wireless, the resemblance to the CX 400BT is undeniable. They share the same housing design, but with some smoother edges and an all-black logo. If you weren’t a fan of the CX’s bulgier shell then you might not be enthused by its return here. I felt that once you twist them in, they can be quite comfortable, but those with smaller ears may not feel the same. The housing remains firm and holds a tight grip within the ear cavity, as the spout helps support the body with a natural grasp. 

Sennheiser ear tips

Design and Functionality

Sennheiser brings over their 7mm true response transducer to the CX true wireless. This dynamic driver unit is featured in other models like the IE 300 IEMs. It features a wide-band system that’s one of the smallest available and focuses on delivering a larger soundstage. In terms of its controls, the CX true wireless also brings over the interchangeable touch interface from the CX400BT. Using the Sennheiser mobile app, you can customize how you want the functions to work. You can make it so only one earpiece activates play/pause while the other can be strictly used to increase volume with a single touch. The controls themselves are responsive after a short delay and a satisfying feedback beep. Additional features on the Smart Control app include an EQ that comes with a good number of presets and some parametric style customization. Lastly, while taking phone calls the CX true wireless will go into a passive noise-canceling mode which greatly reduces ambient noise while on the phone.

Sennheiser open


The connection on the CX true wireless is solid. I never experienced any dropouts, and the resolution came in crystal clear. CODECs featured here include AAC, aptX, and SBC. This is standard for the price, but seeing aptX HD would have been nice. 

Sennheiser logo

Battery Life

You’ll be able to get nine hours of playtime off a single charge of the earbuds, which is sizable compared to other models in this price range. Along with the charging case, you should get 27 hours total. That’s surprisingly not as big as some other models, but the single charge holds enough battery life to get you through a few days of commute. 

Sennheiser ear tips


Although I don’t normally equate true wireless earphones with good soundstage, Sennheisers past models have proved otherwise. The Momentum 2 true wireless has one of the better stages for a Bluetooth earphone and it resonated with the CX models. Here you get a wide stage that appears both accurate and expansive. This is one of the most spacious true wireless earphones you can get, sporting an excellent amount of separation and air between elements. It doesn’t quite reach the imaging of the Momentum but gives off just enough clarity to help it stand out among its competition. 

Low End

Sennheiser packages the CX true wireless with a “bass boost” insignia on the box. To my knowledge this is part of the presets included when using the EQ on the Smart Control app. Using the earbuds without the EQ, the bass is still very satisfying. Its got a good thumping response, with a rich timbre. Boosting these frequencies only brings out the depth of the lows, even more, highlighting a resonant tonality that adds an ever greater impact.


When I normally hear Sennheiser products, I always have a certain idea of a clean, balanced timbre in the midrange. That’s almost exactly what you get here. It’s an almost crisp response but falls to a few notches in the upper mids. This makes vocals appear present and clear but without accentuation. There’s still a lot of detail here to be enjoyed, with instruments and effects receiving a lot of room for expression. If the sound signature just had a bit more coloration here it would be one of the best around.


Some of the treble frequencies have a surprising sharpness to them. It’s not quite a shine, but a piercing quality that could make or break whether or not this sound signature is for you. I wouldn’t describe it as harsh, but you can use the EQ to attenuate some of the CX’s more treble-heavy elements. I enjoyed the more prevalent treble, as it helped add fullness to the sound signature and add some considerable height. 


I believe Sennheiser has knocked it out of the park with another great true wireless. As an update of the CX400BT, it’s more arguable on which one is superior. The sound signature has a lot to offer, with a wide soundstage and a balanced timbre with a ton of customization due to Sennheiser’s Smart Control EQ. There are many true wireless earphones out there with the same price, but the CX true wireless will probably be the most consistently satisfying one you’ll hear. That housing shape might deter you if you have smaller ears, but in turn, you’ll get a rich timbre with great detail.

Pros and Cons 


  • Interchangeable controls
  • Custom EQ
  • Punchy bass
  • Clear mids
  • Wide soundstage


  • Size may not be suitable for smaller ears
  • Limited CODECs
  • Charging case battery life

The Sennheiser CX True Wireless is available to pre-order at Audio 46.

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Alex S. is a sound designer and voice-over artist who has worked in film, commercials, and podcasts. He loves horror movies and emo music.