These true wireless earbuds are about sound more than anything else. Neither pair has the kind of water or sweat resistance to be considered "durable," but they do excel in the audio quality department. Where they differ is in how well they fit, ANC support, and price. It's a closer race than it might seem for two pairs with that kind of distance between them, and it all comes down to what you feel you need.
Sennheiser Momentum True Wireless 2 vs. Sennheiser CX 400BT: Hearing clearly
Sennheiser has been consistently good at making great headphones, including true wireless earbuds, except you have to pay a premium to hear that sound in the Momentum True Wireless 2 (MTW2). The calculus has changed with the CX 400BT, though they aren't dramatically different on paper save for a few key metrics.
|Sennheiser Momentum True Wireless 2||Sennheiser CX 400BT|
|Bud battery life||7 hours||7 hours|
|Charging case battery life||21 hours||13 hours|
|Connectivity||Bluetooth 5.1||Bluetooth 5.1|
|Digital assistant support||Google Assistant, Siri||Google Assistant, Siri|
|Supported audio codecs||aptX, SBC, AAC||aptX, SBC, AAC|
|Speaker size||7mm drivers||7mm drivers|
|Active noise cancelation||Yes||No|
One thing not noted in that chart is that the CX 400BT not only don't have ANC support but they also have no ambient mode. Transparency mode in the MTW2 uses the onboard mics to filter in background noise for extra safety on a busy street and to enable conversation without removing the earbuds. Missing that feature does add a certain level of inconvenience when wearing the CX 400BT.
This isn't to minimize the lack of ANC support. It's one of those features you appreciate having when it's there, and the best the CX 400BT can do is good passive noise isolation. On the other hand, the MTW2 cover both scenarios for how background noise may be relevant to you as a listener. They also have more battery life coming from the case, amounting to an extra full charge for the MTW2 over the CX 400BT.
Another tangible point not on the chart is the difference in size. One thing Sennheiser did with the MTW2 was shave down enough of the frame to make them just a little more comfortable than the first generation was. That kind of contrast applies here, too, because the CX 400BT feel slightly larger than their pricier counterparts.
And yet, Sennheiser made the same mistakes with the onboard controls. Too finicky and sensitive, the CX 400BT is actually an improvement in that area, though there is an advantage in that their touch controls don't have as many functions.
Sennheiser Momentum True Wireless 2 vs. Sennheiser CX 400BT: It's about the audio
Despite their technical differences, fit and comfort are equally important for both. They each come with four sets of ear tips to help create the tight seal necessary to bring out the most of the excellent soundstage they're equally capable of. But neither one could be considered "small" in stature. They're generally thicker than many top-class competitors are, and that could be a problem if your ears don't leave as much room for them.
On paper, Sennheiser equipped both earbuds the same way as it relates to audio fidelity. They have 7mm drivers and support the same codecs, including aptX for higher quality listening on Android phones. With Sennheiser's Smart Control app, you also get some useful tools to work with, namely the equalizer.
The MTW2 sound better right off the bat, whereas the CX 400BT need extra help from the app's EQ to get more out of the sound,
The two diverge out of the box. The MTW2 sound better right off the bat, whereas the CX 400BT need extra help from the app's EQ to get more out of the sound, which is oddly dull and lacking bass from the outset. Once you tweak it the right way, the CX 400BT come alive and Sennheiser's excellent soundstage finally comes through. Even with that helpful hand, however, the MTW2 still hold an edge in audio quality when you do the same with it. It's not huge, mind you, but it becomes apparent after listening to these two pairs long enough.
Of course, they also have the benefit of ANC to reduce the challenge of listening clearly in louder conditions. Sennheiser does ANC well, even if it's not the best on the market, and you would expect such a feature from a pair of earbuds in the $300 range.
Phone call quality is about the same in both models. You'll likely hear better with the MTW2 because of ANC and transparency mode, but in quieter locations, there's not a huge difference. The onboard controls are also the same (you can customize them in Smart Control), and you can answer a call with either pair by just taking out the right earbud out of the case when someone's calling.
You won't get too many choices in color either way. The MTW2 come in black or silver, while the CX 400BT come in black or white.
Sennheiser Momentum True Wireless 2 vs. Sennheiser CX 400BT: Which should you choose?
There isn't really a wrong choice between these two. Sennheiser's goal was to offer something that carried the company's sound pedigree at a lower price in the CX 400BT. But the MTW2 are the clearer winner because they're simply more versatile, both in the extra features they offer, and in their smaller size, which should fit a greater variance of ears. The extra battery life out of the case doesn't hurt, too.
And it's those extras that you're ultimately paying for. The price difference is all about that, since the sound quality alone isn't enough to justify it. The CX 400BT come out looking like a bargain — so long as you're cool with what you don't get out of them. If your budget allows, you will get a more fully-loaded experience with the MTW2.
A clear earful
Sennheiser Momentum True Wireless 2
Sound and clarity at once
Sennheiser is back with an encore and makes up for lost time by putting together one of the best true wireless earbuds with improved battery life and active noise cancelation.
Not so noisy
Sennheiser CX 400BT
Hearing clearly for less
Cutting down the feature set and price, yet keeping much of its distinct sound, Sennheiser offers a viable alternative for those who value great audio quality.
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