Sennheiser CX 400BT True Wireless earbuds review

When the Sennheiser CX400BT released with a $299.95 price tag, it was a hard pair of wireless earbuds to recommend but the new $149.95 retail price changes things completely. At close to $300, no active noise cancelling and no water resistance were two big compromises to make for what was still a premium price tag and spending a little more could get you a whole lot more from Bose or Jabra.

For under $150? You bet they're worth it. What you're getting is a classy pair of comfortable wireless earbuds with the same internal hardware and audio performance as the company's more expensive Momentum 2 earbuds, just without the luxuries of active-noise-cancelling and water resistance.

Before we dive into the details, let’s discuss the price. $299.95 was already a decent price for a pair of true wireless earbuds with the same overall performance of Sennheisier’s flagship Momentum True Wireless 2 but the price has since been cut down by a whopping 50%, bringing the current retail price down to $149.95. If you’re looking for a stellar pair of true wireless earbuds for under $200 (and can do without water resistance or active noise cancelling), you’d struggle to find something better than the CX 400BT at that price.

Here’s where you can buy the Sennheiser CX 400BT earbuds in Australia:

Like its premium Momentum counterpart, the CX 400BT has a slick modern design that manages to look fancy without drawing too much attention. The CX 400BT isn't quite as compact as the Momentum 2, opting for more of an oblong shape, but the buds themselves weigh the same (6g per bud). It also drops the textured silver touchpad in favour of a more muted plastic touch panel. The different form factor feels a fraction bulkier than the Momentum 2 but oddly enough it's better off for it. One small frustration of the Momentum 2’s design was that the smooth rounded edges made the earbuds hard to grip and easy to lose. The more rectangular design of the CX 400BT earbuds makes it a lot easier to keep a hold of when removing and returning them to the charging case.

Speaking of the charging case, it’s also had a bit of a redesign. Sennheiser has kept the luxury fabric wrap exclusive to the Momentum range whereas the CX 400BT has a more traditional plastic charging case with a matte finish. I don't mind the plastic look but it's easily scratched and the scuffs really show.

The charging case is a little taller than the Momentum 2’s case but also a little thinner, shorter and a lot lighter (37g compared to the Momentum 2’s 58g case). The case sheds a few grams but loses a bit of overall battery life in the process (more on that in a moment).

The buds themselves have also been stripped of any degree of water resistance. Where the Momentum 2s offer IPX4 water resistance, the CX400 BTs aren’t graded for water resistance at all. That’s a huge consideration if you plan on using them as gym headphones.

Lastly, the CX 400BT's silicone tips are just as comfortable as the Momentum TW2; which is to say not quite as comfortable as Jabra's wireless earbuds but far from the worst. I've typically got to give the old wingnuts some respite every couple of hours which is probably about as long as a listening session needs to be.

Just like the Momentum 2s, the Sennheiser CX 400BTs have (sadly) opted for touch controls over physical buttons. With that said, both of Sennheiser’s true wireless earbuds offer some of the most intuitive and responsive touch controls we’ve tested. So many premium true wireless earbuds struggle to nail this. Bose’s otherwise phenomenal QuietComfort Earbuds is just one example.

It’s not without its faults but the basic commands are easy to remember: one tap on either bud to accept/end a call, two taps to reject. One tap on the left bud plays and pauses music, one tap on the right bud initiates your voice assistant of choice. There’s a long list of advanced controls if you want to do it all from your buds but the basics are easy to remember. Taps register reliably and double-tapping is made easier with audio cues that let you know when you’ve tapped once, twice etc.

ANC (active noise cancelling) is the other big sacrifice Sennheiser users will make if they opt for the more affordable. Personally, I find the ANC of the Momentum 2s just okay but I’ve also found that Sennheiser’s passive noise cancellation is some of the best in true wireless and has been since the first Momentum True Wireless earbuds. Still, if ANC is a must-have feature there are other brands that have made huge strides with their noise-cancelling technology; Bose recently nailed it with its QuietComfort buds and Sony’s cutting-edge wireless earbuds recently got an upgrade.

In short, if you don’t mind parting with a little more cash, there are some seriously impressive noise-cancelling options out there. But that brings us back to the most important part of this review: the price. Because despite ditching ANC, the CX 400BT is an almost carbon copy of its premium equivalent and listening to music is just as nice.

Most of what I’ve said about the Momentum 2s applies here but I’ll touch on a few things that really shone through this time around. Firstly, Sennheiser’s unrivalled handling of in-ear bass. As someone with an unhealthy appetite for thick bass, I appreciate that kicking the volume up won’t result in any loss of clarity or comfort.

That said, you’ll miss the ANC if you’re used to it (I certainly did coming from the Momentum 2s). There’s just no denying that the Momentum 2’s noise cancelling tech does the already phenomenal audio even more favours. It’s noticeable when you’re trying to immerse yourself in a song like Radiohead’s Reckoner with such a wide soundstage. That said, noise-cancelling aside, the same track still sounds much better on the CX 400BTs than a lot of other earbuds.

At the end of the day, if you want remarkable sound quality without breaking the bank, the CX 400BTs should be at the top of your shopping list.

The one consolation prize you get for missing out on ANC is longer battery life in the buds themselves. Both the Momentum 2 and CX 400BT advertise seven-hour battery life (per earbud) but that number nearly halves if you’re using ANC with the Momentum 2 (which you almost certainly will be). So for day-to-day use, the CX 400BT lasts a little longer. However, the trimmed down charging case (trimmed down in weight alone) also holds a lot less charge overall, clocking 20 hours of charge in the case, compared to the Momentum 2’s 28 hours.

There’s no real reason why the CX 400BT should hold less charge overall. As we’ve mentioned, while the case is certainly lighter, it’s roughly the same size with slightly different dimensions. The cynic in me says the difference in overall battery life is just another way to justify the huge price difference because I really can’t see any other reason why there would be such a huge gap between the two models. The Momentum 2 has a battery life far above the average for true wireless earbuds (that we’ve reviewed, whereas the CX 400BT falls just below the average. In the scheme of things, the CX 400BT still have good battery life and maybe a bigger battery would bump the price too close to the Momentum 2 but it's hard to ignore the fact that you could spend roughly the same price (at full RRP) on the Galaxy Buds Pro and get better battery life and the option of ANC.

At the full $299.95 RRP, we’d hesitate to recommend the CX 400BT wholeheartedly but at $149.95, they’re selling at a steal. What you’re getting here is the same hardware and audio quality as the Momentum True Wireless 2 earbuds at a fraction of the cost. Yes, you’re sacrificing active noise cancellation and water resistance but if you’re after those features plus the level of sound quality these buds deliver, you’ll be paying a lot more.

The Sennheiser CX 400BT's sound quality is amongst the best in its price bracket when compared to other wireless earbuds. If you're looking at spending below $200 on a pair of buds, these should be a top consideration.