Sennheiser CX 400BT Review: Simple Earbuds With Impressive Sound Quality

By Yvonne

Sennheiser CX400BT review: Earbuds Simple With Amazing Sound Quality. Sennheiser CX400BT earbuds have a solid battery life, and excellent sound quality. They are the most simple but effective earbuds on the market. They lasted 18 hours.

Sennheiser CX 400BT True Wireless

Sennheiser CX 400BT

We like this

  • Amazing sound quality

  • Battery life is quite good

  • When on sale, pretty affordable

  • Included is the aptX codec

The Things We Hate
  • Lackluster design

  • Quality of construction is not as good as it should be

  • A limited, basic feature set.

Although the CX400BTs offer one of the most impressive sound experiences in true wireless, there are some shortcomings.

Sennheiser sent us a unit to review for one of the writers. For the complete review, please read on.

Sennheiser CX400 BT wireless earbuds is a pair from the audio company that focuses on fundamentals. In a space where wireless earbuds are trying a lot of features to differentiate—from Qi wireless charging cases to active noise cancellation—it's rare to see something simple. The CX 400s are a great choice because they keep costs down and provide a powerful, clear sound that will exceed all expectations.

To be honest, you'll find a number of features that are expected, such as premium Bluetooth codescs for excellent sound quality, decent battery life, and decent but not overwhelming, charging times. The goal is to provide high-quality, clean audio. I was curious to find out if these promises were true. You can read my hands-on evaluation to see how these compare against more advanced competitors.

Related Reading: Apple AirPods Pro Review: Excellent for Apple Fans

Design: This is a unique design, though a bit boxy.

Sennheiser has never been the best in headphone design. Their studio earbuds are larger and more bulky than their competitors, which is why they have a lot of popularity. CX 400s have a matte finish that feels premium and an outer edge with a shiny plastic plate featuring the Sennheiser logo is added.

Its shape is what makes the design stand out. The CX 400s have a rectangular shape from the outside. This is in contrast to the other wireless products that are oval or circular. Although the shape gives the earbuds an individual look, they feel bulky and boxy once you place them inside your ears. This design has implications on how your earbuds fit inside your ears. I will cover those in the comfort section.

Sennheiser CX 400BT

Even though the case's dimensions are quite square, it feels good. This is where simplicity comes in, but not always in a positive way. If you want earbuds that look expensive, these really aren't it—which makes sense, considering these are on the cheaper end of Sennheiser's catalog.

Related Reading: Aminy UFO Review: Looks Can Be Deceiving

Comfort: It's good enough but requires some finesse

One pair of Sennheiser wireless true wireless headphones (the original Momentum wireless earbuds) was also tried, and I found the CX 400s to be very close in fit and comfort. The majority of the earbuds are constructed within the enclosure. There is a tiny circular tip that protrudes from the enclosure. The earbuds will stay in place by fitting into the enclosed eartip (there are 3 sizes). You can then rest the larger enclosure against your inner ear.

Sennheiser CX 400BT

The CX 400s don't fit perfectly because of their squared off design. It doesn't fit everyone's ears. A secondary grip point, such as a rubber wings, is what I prefer for earbuds. These earbuds aren't very comfortable and don't last long. It feels like I am constantly pressing the earbuds into my ears. This is not ideal, but it is particularly annoying, as these earbuds have touch controls that I can use to adjust them. These might work for certain ear sizes and shapes.

You can then gently contour the larger enclosure to fit against your inner ear. The CX 400s' fit may not be perfect as the squared-off shape doesn't always fit all ears.

The CX 400s' tiny 6-gram weight per earbud makes them light.

Related Reading: Senso ActivBuds Wireless Headphones Review: Affordable

You might not want to pay for durability and build quality.

It is difficult to grasp the feel of these Sennheiser earbuds made from plastic. There is little to worry about these earbuds scratching or scuffing in any significant way. It is also a cheap, thin-feeling, plastic covering the entire case as well as most of the enclosures. Although this does make the earbuds lighter than more bulky options, I prefer the Bose-feeling plastic that you will find in the QuietComfort or SoundSport line.

Sennheiser's Momentum Earbuds have a cloth-like, woven covering that covers the battery box. This makes the entire package feel more premium. Although the CX 400's case doesn't easily open, the lid does make a clicking sound when closed. The magnets that pull the earbuds into the case are strong. The price is reasonable, but the experience of using the earbuds does not feel excessively expensive. These earbuds don't have an IP rating so they shouldn't be worn in the rain. However, I think that they will work well for workouts.

Sound quality: A remarkable marquis feature

The CX 400's true highlight is their sound quality. This is not surprising given Sennheiser’s expertise in this area. These earbuds have a lot of positive points. This earbud range covers 5Hz to 21kHz. It is the largest frequency response I have seen in a sized and category earbud. Sennheiser's 7mm driver in each earbud is slightly larger and feels very powerful considering its form factor.

These earbuds are a great way to listen and I am confident that the majority of your money is being used for a good listening experience.

Sennheiser promises a lower than 0.08 percent harmonic distortion in its drivers, which is quite an improvement over most other category earbuds (though it is still affected by Bluetooth transmission).

These earbuds are a great way to listen and I am confident that the majority of your money is being spent on a good listening experience. All music sounds natural and has a sound ground that allows it to breathe, which makes it feel more alive than earbuds can sometimes do. Spoken words are also clear and crisp, which makes for an excellent podcast or radio experience. The phone calls are impressive, even though the microphone is located on the left ear. This is especially important for people working remotely or conducting video calls.

Sennheiser CX 400BT

These earbuds are great for their sound quality and even have transparency or active noise cancelling modes.

Battery life: Good, but not too impressive

CX 400s are in the middle range of battery performance. They offer both the longest and the shortest battery life. Sennheiser claims you'll get about 7 hours on a single charge in the earbuds—a respectable total that will get you through your commutes and a full workday—and you can add an additional 12 or 13 hours with the battery stored in the case. The best earbuds have a battery life of over 25 hours. However, the worst earbuds can last only about 12 hours. This 20 hour usage is quite reasonable but not great.

My expectations were not high, but the Sennheiser Momentum Earbuds had a terrible battery life. Although the Sennheiser Momentum earbuds have been reduced in size, the battery lasts longer.

The latest trimmings for Connectivity and Codecs

These earbuds feature Bluetooth technology that supports great sound quality. Bluetooth 5.1 is the protocol that drives wireless connectivity. This means there are support for multiple devices and 30 feet wireless range. It also makes it possible to establish a very solid connection. Although I was amazed at how strong the connection was, I experienced one issue when I connected them to my computer for the first. It was easy to reconnect them by pressing simultaneously on the two earbuds.

These earbuds feature Bluetooth technology that supports great sound quality.

You will find all the usual headset and playback profiles, such as A2DP and HSP. You'll find the lossless and standard SBC options and AAC options. However, aptX can also be used if your device is compatible. Qualcomm has created a clever codec that allows music to be compressed, transmitted faster and with less degradation to its source files. This codec is very useful when you want your earbuds to sound amazing. It means more of the source music will reach your ears.

Codecs include the lossless and standard SBC options and AAC. However, aptX can also be used if your device is compatible.

Software, controls, and extras: Simple, clean package

It's not much to discuss here. You can control the controls by tapping the touch panel on your earbuds. A tap on the right will call up voice assistance. Tap on the left earbud to pause music and answer calls. The app allows you to customize certain functions, but the overall controls are the same. The battery case has one button, however it does not activate pairing mode. Instead, it is an indicator button that shows how full the battery case is.

Sennheiser CX 400BT

The Sennheiser Smart Control App gives you a little more control, although it's a lot simpler than other apps (I'm thinking of Sony). Sennheiser's EQ is very well handled. You can choose from a classic, curve-based graphic EQ or a more flexible slider-based option. The earbuds sound great right out of box. However, I prefer a heavier bass. The earbuds can be programmed to respond differently depending on what you tap. You can even set a feature that will allow the headphones to accept calls from your smartphone while they are in the case.

Prices: Good value especially when on sale

The earbuds are priced at $200 and feel great. You can find deals starting at $149 and ending at $129. The excellent sound quality is made all the more appealing by these low prices. Although $199 seems reasonable given the battery life, the brand name and price, it's possible to save some money if you wait. Although it would be nice to have a bit more premium material, such as a better-quality plastic, this is not a major issue for a solid package.

Sennheiser CX 400BT vs. Apple AirPods

The CX 400BT and CX 400BT are so comparable in price, it is easy to compare them. However, Apple Airpods is the original wireless device that launched all of this: they have the same pricing. While neither product has active noise cancellation, both can be used with touch controls. The connectivity between the two products is good. The CX 400s will provide a better audio quality and more customization (thanks to their interchangeable eartips), but the AirPods will feel premium and work with Apple devices more smoothly.

Final Verdict

An affordable, but solid earbud option.

Sennheiser's CX400 BT Bluetooth earbuds are both an enticing, true wireless product and completely uninteresting pair. These earbuds do everything right, including solid sound quality and decent battery life. There's not much to be excited about. There won't be ANC here and you won't get a premium feel. However, that may not matter to you. If you value great sound quality and have a long history with Sennheiser, the CX 400s will be able to carry Sennheiser’s legacy.

Sennheiser Momentum True Wireless Earbuds

Sennheiser PXC 550

Sennheiser HD1 Bluetooth Wireless Headphones Free


  • CX400BT True Wireless Product No.
  • Product Brand Sennheiser
  • SKU 6423644
  • Prices from $199.95
  • September 2020 Release Date
  • Weight 0.2 oz.
  • Product dimensions 2.3x1.66x1.3in
  • Black and White
  • Battery life 7 hours with earbuds, 19 hours when using a battery case
  • Wired/Wireless wireless
  • Wireless range 30 feet
  • 2-year warranty
  • Audio Codecs SBC, AAC, aptX

Learn more:

5 Methods to Download Videos from Pornhub | Top 5 Pornhub Downloader Review [2022]

Top 10 Useful Vtuber Software to Start as a Vtuber [2022 Update]

How to Download Videos from Xvideos?