One of those times is when you're running or working out, as we've all heard horror stories of the likes of AirPods (2019) falling into manholes, never to be seen again.
While Sennheiser is certainly following the trend with its Sennheiser Momentum True Wireless earbuds, it's reassuring to see new wireless buds that don't entirely ditch the cable for those who want it – like the CX Sport wireless running headphones, which combine Bluetooth connectivity with the security of having a wire between the two buds.
- What are the best running headphones of 2019?
Price and availability
Sennheiser is no stranger to true wireless audio, having released its flagship Sennheiser Momentum true wireless earbuds in 2018, but it hasn't abandoned standard wireless earphones by any means.
Sennheiser has a number of wireless in-ear and over-ear headphones, including the Momentum Frees, which we rated highly when we reviewed them.
The CX Sports are less expensive than the Momentum Frees, coming in at $129.95 £119 / AU$199.95, sitting square in the middle of the price range for similar headphones.
You can get fantastic wireless earphones for less, though; the Optoma NuForce BE Sport 4 is one of our favorite models, and costs around $70 £70 / AU$130.
Design and features
Like many sports-oriented devices, the CX Sports are black with neon accents – and they look quite attractive.
They've been designed with comfort in mind, with rubberized ear fins that keep them snug in your ear while you're working out. In the box you get three different ear fin sizes as well as four different ear tips, so you should be able to find the right fit for you fairly easily.
The buds themselves are small and compact, and we thought that they felt secure and comfortable when we tested them.
With runners in mind, the CX Sports have an IPX4 splash-proof rating. This means they should be able to withstand a sweaty workout session, but you probably shouldn't take them into the shower with you post-workout.
Another helpful feature for listening on the move is the inclusion of an inline remote underneath the right earbud, which contains volume and play/pause buttons, as well as a built in microphone.
Sennheiser says the CX Sports have a battery life of six hours, and can be quick-charged via USB in ten minutes to "offer a further hour of playback", and can be "fully charged in 1.5 hours".
We found the stated battery life to be accurate in our tests, and the ability to quick-charge is a fantastic feature if you listen to music while commuting (and frequently forget to charge your headphones the night before).
- Read our round up of the best running headphones
The first thing you'll notice about the Sennheiser CX Sports is how full-bodied the bass is.
We listened to bury a friend by Billie Eilish, and we were blown away by the powerful sub-bass synths, wavering pads, and vigorous percussion.
Vocals also sound great, with a smooth yet detailed quality that gives a gorgeous emphasis to every lyric. Despite the power of the bass frequencies, we didn't experience any bleed into the mids, which can often be a problem with bassier headphones.
Saying that, we would have liked a little more power behind those mid-range frequencies. While the Sennheiser CX Sports handled the bass riffs of Childish Gambino's Feels Like Summer admirably, we found ourselves missing some richness in the vocal harmonies of the chorus – but that's if we're really nitpicking.
Wanting to test them out on something more treble-y, we listened to M7 by Seba & Ulrich Schnauss. Clattering synths and sonorous chimes had a brilliant level of clarity, with a sweet tone throughout.
Overall, these sporty buds have a very warm, open sound, with a well balanced soundstage that lends itself to bass-heavy workout music, R&B, and pop.
As well as supporting Bluetooth 4.2 apt-X for high quality wireless audio, they also support apt-X Low Latency, which means you shouldn't experience any lip-syncing issues when watching videos – that is, if you have a compatible display like the Samsung Galaxy S9.
In terms of connectivity, the CX Sports performed well, and we didn't experience any Bluetooth dropouts in the time we were using them. They also paired with our iPhone SE very quickly, which is ideal if you're listening on the go.
Sennheiser's CX Sport Wireless earbuds are all about that bass – which is ideal if you're looking for a pair of headphones that will bolster your running performance.
That's not to say they aren't well balanced; the CX Sports provide impressive audio quality across the board, and we were equally impressed by the clarity they provide to treble frequencies, even if we occasionally craved some more richness in the mid frequencies.
The sports-oriented touches that Sennheiser has given to the CX Sports could well make them the ideal workout headphones, with an attractive and rugged design and a comfortable fit. Of course, that lime green design won't appeal to everyone, but we liked it.
They can't compete with the low price of the Optoma NuForce BE Sport 4s, which also boast a higher 10-hour battery life, but they might just beat them in terms of audio quality . Whether that's worth spending an additional $40 on largely comes down to how bassy you like your workout music.
- Read our round up of the best wireless earbuds