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Motorola S11-Flex HD review: A headset best for the gym, not making calls.

Enjoy hands-free audio and make smartphone calls with the Motorola S11-Flex HD Bluetooth headphones.

Brian Bennett

Brian Bennett

Senior writer

Brian Bennett is a senior writer for the home and outdoor section at CNET. He reviews a wide range of household and smart-home products. These include everything from cordless and robot vacuum cleaners to fire pits, grills and coffee makers. An NYC native, Brian now resides in bucolic Louisville, Kentucky where he rides longboards downhill in his free time.

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4 min read

If you’re looking for a laudable gym buddy, the $129.99 Motorola S11-Flex HD has a lot going for it. The stereo Bluetooth headphones shrug off sweat and exposure to moisture, plus once adjusted stay firmly in place. It’s an adequate music player, too, and lets you take that important phone call if you need to. Just don’t make a habit of it, since the device’s call quality is subpar at best.

Motorola S11-FLEX HD

Motorola S11-Flex HD

The Good

The <b>Motorola S11-Flex HD</b> is lightweight, wireless, sweat resistant, and comes with lots of ways to adjust its fit. The headset also charges quickly.

The Bad

The S11-Flex HD is tricky to strap on and delivers mediocre call and audio quality.

The Bottom Line

Motorola’s S11-Flex HD makes for a great workout companion but phone calls aren’t its strength.

The Motorola S11-Flex HD, a headphone with many talents (pictures)

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When you first see the S11-Flex HD, it’s clear the device has a pretty wild-looking design. Unlike most of the wireless stereo headphones on the market, which tend to be on-ear or earbud styles, the S11 uses an over-the-ear design. These kind of headsets are typically tough to position comfortably, especially for eyeglass wearers like myself. Motorola tries to solve this by crafting the S11-Flex HD to be highly adjustable.

With its unconventional design, it's hard to tell at first which end is up. Sarah Tew/CNET

For instance, you can pull the earbud stems up and down. They also swivel a bit too. The headband is flexible as well and Motorola also bundles fours sets of different sizedeartips to accommodate large and small ears. Additionally, you can attach a rubber strap for greater stability.

The earbuds swivel and tilt to offer a more comfortable fit. Sarah Tew/CNET

Even so, I found that it took a good 6 to 7 seconds to place the S11 properly on my ears and over my glasses. Once in position the headset does firmly stay put, especially when I used the stabilizing rubber strap. Without this strap the back of the headband is easy to dislodge, either by the back of collared shirts or jacket collars when I tilted my head upward.

I was glad the S11 came with those extra eartips as well, since the standard ones installed by default were too big for my taste. Attaching the smallest tips available helped me to create a tighter audio seal since I could jam the earbud deeper into my ear canal. Controls are minimal on the S11-Flex HD, with only a power button and volume rocker on the right side and a multifunction button on the left. At just a hair less than 2 ounces, the device is lightweight too, a boon for those taking it on long runs or runs. Also thoughtful is the S11’s sweat-proof construction, thanks to a moisture-repellent coating.

Extra eartips and a strap are included for more stability. Sarah Tew/CNET

Essentially the Motorola S11-Flex HD is designed to provide wireless stereo audio for listening to music during workouts at the gym, or while just walking around town. The device also can pair with Bluetooth-equipped phones to function as a traditional hands-free headset for making and receiving calls.

Another important skill the S11-Flex HD has in its tool kit are dual microphones for enhanced noise canceling on calls, which Motorola claims matches your typical mono Bluetooth headset built solely for this purpose. There’s also a range of baked-in equalizer settings to better match the music you’re listening to. For example, there’s one for bass-heavy tracks, another for vocal and acoustic genres, and a balanced mode to cover most audio situations.

Motorola definitely makes some bold claims concerning the S11-Flex HD’s capabilities but I’m sorry to say the device doesn’t quite live up to much of the hype. Pairing the headphones with my test handsets, the Motorola Droid Razr Maxx HD (Verizon) and Samsung Galaxy Nexus (unlocked), was a cinch. I simply pressed the power button and the device immediately placed itself into pairing mode for 5 minutes. I then scanned for the device in my test phone’s Bluetooth menu and linked to the S11 within a few short screen taps.

Audio quality for music streamed from my handset was acceptable but not outstanding.For instance, I didn’t experience as much bass as I have from larger over-ear models. Also, sound didn’t have an open quality, something I appreciate in premium headphones.

Even eyeglasses wearers can strap these on. Sarah Tew/CNET

Additionally, calls that I made on either of my test phones and linked to the S11-Flex didn’t deliver the crystal-clear audio quality Motorola promises. Callers immediately knew I was calling from a mobile phone or even accused me of dialing over a speakerphone. While people on the other end sounded fine to me, callers reported that my voice was robotic and flat to their ears, as well.

Motorola says the S11 will provide up to 7 hours of talktime, 6 hours of audio playback, and a standby time of 6 days. The device features a rapid charge function too, which will allow 1 hour of operation after merely charging for 5 minutes. My experience was in line with these claims and I was able to charge the device quickly.

I’ve long dreamed of owning just one wireless pair of headphones that could serve all of my daily needs. In the same spirit, the $129.99 Motorola S11-Flex HD is a good attempt to merge a fitness-minded stereo audio device with a dedicated Bluetooth headset for hands-free calling. The S11 certainly offers plenty of ways to adjust its fit to your personal needs, with multiple eartips and a stability strap in the box. It’s a bit tricky to strap the S11 on quickly and its audio quality certainly won’t blow you away, especially on calls. If you really want to have your cake and eat it too, I suggest springing for two products. First is the $79.99 Monster iSport Immersion In-Ear Headphones, which are better suited for gym duty thanks to great sound quality, and a supersecure fit. Second, you just can’t beat the clear call quality the $99.99 Plantronics Voyager Legend headset provides. Otherwise, the Motorola S11-Flex HD is a decent compromise as long as you don’t expect to fall in love.

Motorola S11-FLEX HD

Motorola S11-Flex HD

Score Breakdown

Design 6Features 7Performance 6
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