Review: Sennheiser CX Sport

Testing workout earbuds requires an entirely different set of metrics than regular in-ear headphones. More than anything else, workout earbuds need to stay put. Running is hard enough without constantly flibberting with something in your ear canal.

Other factors that might be big pluses when you're sitting at your desk are not so great when you're in motion. Excellent noise filtering is less attractive when you might get mowed down by a cyclist. And mediocre sound quality can be forgivable in this case, too. While I enjoy a wide variety in my music while cooking, cleaning, or working, my exercise playlists tend to resemble a frat party circa 2005.

All of these conflicting design needs mean that fitness-focused headphones can be hard to get right. Take, for instance, the Sennheiser CX Sport headphones, the latest addition to the company's acclaimed CX line. They feature Sennheiser’s top-notch sound in a tough, lightweight, splash-proof package, and they're not bad at all. But in my opinion, if you're looking for headphones that are exclusively for working out, you might find better ones for the price.

Inside the box, you get three sets of ear fins, four sets of ear adapters, a pocket-sized neoprene storage pouch, a cable clip, and a USB cable. The headphones themselves are what you might call a wired wireless set, with a cable that runs around the back of your neck and a small volume control set on the wire leading to the right bud.

Most workout headphones have some variation of this ear fin design. They don't catch the wind like a loop does, and it's easier to wear hats and sunglasses when you don't have over-ear buds taking up already-limited real estate. Finding the right set of fins and tips took some experimentation, but after two or three tries, I eventually found the right combo.

To fit the buds, I pushed the tips in my ear canal and then twisted to lock the rubber fins into my ear folds. Over two weeks, I wore them while running, hiking, walking my dogs, and climbing at the gym. You could say they were rock-solid (ha!). Once I had the fit figured out, nothing I did could shake them.

They weigh only a little over 15 grams, so they were barely noticeable in terms of weight. And the foam tips did an incredible job at filtering out ambient noise. I ran past a pavilion filled with people barbecuing, partying, and playing music, and didn’t hear a thing. Cyclists almost nailed me, but luckily, I just stuck the buds back in my ears and didn’t hear whatever vulgarities they said as they were passing.

The headphones feature Bluetooth 4.2, Qualcomm apt-X, and apt-X Low Latency, all of which purport to deliver high-quality audio over a stellar wireless connection. The connection was excellent. My rock gym has a 60-foot climbing ramp, and I was able to leave my phone at the base of the ramp and do circuits while listening to podcasts without it cutting out.

Sennheiser states that the CX Sports have a six-hour run time, and with an hour or two of working out and walking the dogs every day, I needed to recharge them every three to four days. This isn't as long a runtime as other headphones I've tested, but I could also pop them into the charger for ten minutes or so to get enough power to last through a 30-40-minute run.

Their waterproofing is rated at IPX4, which offers splash protection for five minutes. I briefly contemplated, then decided against wearing them in the shower to give the seals a rigorous test. But I did wear them in my sweaty ears and against my sweaty neck, and I did get caught in a brief, whirlwind summer rainstorm. The headphones kept right on trucking.

I also really liked the included neoprene pouch, which is much nicer than many other pouches you might get for free with headphones.

I listened to podcasts and everything from Missy Elliott to George Strait, Queen, Pearl Jam, and electronic music like CHVRCHES. The sound quality is excellent, especially in the upper registers. Violins and the ringing of strings strumming sound crisp and clear. I did find the bass presence to be lacking, as compared to two other sets of workout buds that I'm currently testing. But if your workout playlist contains 80 to 100 percent less Lil Jon than mine does, then you might not notice.

The CX Sports have the capacity to connect to two devices simultaneously, which sounds like a convenience but usually worked against me. They connect automatically to any device with Bluetooth capabilities when you turn them on. Both video chats on my computer and calls on my iPhone dropped out when I had both devices connected simultaneously.

I also forgot they were connected to my laptop on Every. Single. Run. I walked out my front door, ready to crank it to the dulcet tones of My Favorite Murder, the headphones urgently and repeatedly notified me that they'd lost connection until I stopped to turn them off and restart them out of range.

All in all, the CX Sport do a very decent job of pulling double duty as workout headphones and everyday ones, if you can remember which device is connected. They filter out noise well and stay put, and if you forget to recharge them, you can get enough of a charge for a decent run while you're finding and tying your shoes.

But, if you're looking for dedicated workout headphones and you, too, crib your workout playlists from DJs at Miami nightclubs, you can find others at this price that might serve you better. These are very good headphones that succeed in the areas where fitness-focused models need to excel, but they're just not for me.