Sennheiser CX 400BT True Wireless Earbuds – Bluetooth In-Ear Headphones for Music and Calls – with Noise Cancellation and Customizable Touch Controls, black


In my personal top, Sennheiser’s MOMENTUM True Wireless second-generation TWS earbuds take first place. After testing this pair of headphones, I was impressed by the sound and bought myself one.

But in the world of wireless sound, the competition is such that the buyer votes with a ruble and wants everything cool but cheaper. Sennheiser listened to the audience’s wishes and released the Sennheiser CX 400BT True Wireless model, retaining great sound but cutting the price by 20%.

Related: Sennheiser MOMENTUM True Wireless 2 Review

Sennheiser CX 400BT Review: Design

The headphones are laconic and follow the principle of reasonable minimalism: small, neat, and comfortable in shape. The body is made of matte plastic in black or white.

I liked the way they sit in the ears. You can shake your head or jump – they stay in place and are firmly fixed. Be sure to try different complete attachments, so it will be easier to find harmony when paired with headphones. They will feel like a part of themselves and delight with sound.

Sennheiser CX 400BT Review

I would also like to praise the Sennheiser CX 400BT True Wireless for the quality of noise isolation. There is no active noise cancellation system, as in the older model, but with well-chosen nozzles, the extraneous hum is cut off, and thanks for that alone.

Sennheiser CX 400BT Review

They do not splash and sweat-resistant, so keep this in mind if you will use them for training.

The case for storing and charging the headphones is also made of plastic; outside, you can see the LED activation button to check the LED indicator’s battery charge. The earbuds are fixed inside with magnets. They will not accidentally fall out when you open the cover. Moreover, it is convenient to remove them by pulling on their body.

Sennheiser CX 400BT Review

Sennheiser CX 400BT Review: Control

The headphones do not have physical keys. All control is touch-sensitive. In rare cases, an accidental operation is possible when you adjust the earpiece in your ear or take it out and accidentally touch the touch area with your finger. But this happens rarely, and in general, I have no complaints about this method.

The control principle is the same as in MOMENTUM True Wireless 2. If you want, you can change the control parameters using the proprietary Sennheiser Smart Control app. There you can reassign gestures and customize headphone commanThe the also allows you to update the firmware for your headphones and change the sound using the equalizer. Note that there are no ready-made profiles like “Rock,” “Classic,” and the like. You need to select the sound manually, and experiments are welcome.

Sennheiser CX 400BT Review: Connection

After unpacking, the search for a new device nearby starts immediately. If anything, you manually start the pairing mode if you hold your fingers on the headphones’ touch press for three seconds.

Sennheiser CX 400BT Review

If you listen to music from an Android smartphone, you will be delighted with the support of aptX, but if you prefer iOS, then AAC is used. I will not argue about how critical the difference in sound is. This is a very personal and painful topic for discussion.

Sennheiser CX 400BT Review

The earbuds support Bluetooth 5.1, the connection is stable, and they worked well with different audio sources. This also applies to video playback on the phone. Moreover, no micro lags were noticed when launching a YouTube video.

But there is a caveat: the headphones do not automatically pause the music when you take them out of your ear. Therefore, if you take the earphone out of your ear, you need to touch the touchpad with your finger and only remove it. This is easier and faster than pausing a track while listening to music on your phone.

Sennheiser CX 400BT Review: Music

The headphones were not only surprised. They were very pleased with the sound quality. The Sennheiser CX 400BT True Wireless has the same 7mm, driver as the Sennheiser MOMENTUM True Wireless 2. They play emotionally but without overly rich bass. As it happens, they convey the sound in detail and cope with a variety of music.

Sennheiser CX 400BT Review

The treble is clean, the middle also plays juicy, and the change in volume level does not distort. Just take care of your hearing just in case, and do not overdo it. The power reserve is sufficient.

Sennheiser CX 400BT Review: Conversations

I’m not a fan of talking with headphones. I usually prefer to take them out of my ears and talk on the phone. But then winter came and had to change habits, so the quality of speech transmission through headphones is a critical parameter.

The Sennheiser CX 400BT True Wireless has a pair of microphones in each earphone. It was comfortable to talk on the street – the interlocutors nor I complained about extraneous noise. And on the street, the wind blows, blowing into the hood of a winter down jacket, then the cars buzz and honk – in general, in the city, headphones help to focus on speech, cutting off unnecessary things.

Sennheiser CX 400BT Review: Autonomy

The included case works as a charger for the headphones when not in use. It charges itself via USB Type-C, the charging cable is included in the kit, it remains to find a free block with a USB-A connector. In this case, completely discharged headphones are charged up to 100% in an hour.

The operating time of the Sennheiser CX 400BT is excellent. They can withstand up to 7 hours of operation, and I got about 6 hours on a single charge when listening to music at 70% of maximum volume. I think that if you lower it, then the operating time will coincide with the Sennheiser data. Plus, remember that the cover will always come to the rescue. It will give you another 20 hours of work.

What about MOMENTUM True Wireless 2?

At first glance, it may seem that the CX 400BT headphones copy other Sennheiser headphones, but not all parameters are the same. First of all, the headphones have the same sound quality: they received 7-mm speakers, support for various codecs, voice control, built-in equalizer, and touch control settings.

Simultaneously, MOMENTUM True Wireless 2 has active noise cancellation, IPX4 splash protection, smart pause mode, transparency mode, and a larger battery in the case. The cover is also different: it is larger and with a fabric covering, while the Sennheiser CX 400BT is made of matte plastic but more compact.

Sennheiser CX 400BT Review: Price

Sennheiser CX 400BT headphones’ official price is $199.95, but as of 2nd January 2020, the price has been reduced to $129.95.

Sennheiser CX 400BT Review: Conclusion

The Sennheiser CX 400BT headphones impress with sound. In the world of true-wireless models, they stand out for the quality and elaboration of music while pleasing with a comfortable fit and very decent battery life. It’s just a pity that there is no proximity sensor.

This material was prepared with the support of Sennheiser.

Sennheiser CX 400BT True Wireless Earbuds – Bluetooth In-Ear Headphones for Music and Calls – with Noise Cancellation and Customizable Touch Controls, black


Sennheiser CX 400BT






Noise Cancellation


Battery Life



  • Great Sound
  • Comfortable fit
  • Decent Battery Life


  • No proximity sensor


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