Our editors independently research, test, and recommend the best products; you can learn more about our review process here. We may receive commissions on purchases made from our chosen links.
Lifewire / Jason Schneider
Great sound quality and codecs
Solid battery life
Tired, dated design
Cheap case and cheap look
The Sennheiser HD1 are in-ear Bluetooth headphones from a premium audio brand. Their sturdy fit, great sound response, and excellent battery life make them a worthy option for people looking to go wireless.
The Sennheiser HD1 Free Bluetooth headphones might not be your first choice when looking for wireless headphones. After all, there are dozens of options in the consumer audio market that garner more mindshare than Sennheiser (Bose, Beats by Dre, and Sony). But what Sennheiser offers is a nice mixture between consumer-facing audio and expertly tuned headphones for the pros. The HD1 strike a really nice balance between a premium fit and finish, while keeping a keen eye on sound quality. They aren’t without their faults though. The look isn’t exactly modern and the case and build quality leave just a bit to be desired. We tested them to see what they do right and where they make some missteps.
The look of the HD1 is clearly trying to imitate the sportiness of Beats by Dre. The cable is bisected along its length with half being red and half being black, matching many of the workout-oriented headphones. It does well to make the headphones look striking, even if it is derivative. The ultra-shiny gunmetal casing on the earbuds themselves seems good in principle, but make it feel a little cheap. This isn’t helped by the textured metallic Sennheiser logos on the outside of the casing.
We also found the remote and matching battery casing at the opposite end of the cable to be bulky for the construction. This seems to be how Sennheiser has included NFC connectivity and so many supported Bluetooth codecs, but it doesn’t do a lot of favors from a looks perspective. It isn’t as bad as the bulky neckband versions that some Bluetooth headphones use, like the Bose QC30 for instance, but it isn’t the sleekest look we’ve seen.
The ultra-shiny gunmetal casing on the earbuds themselves seems good in principle, but make it feel a little cheap.
One final point on design: the small plastic loop that holds the wires away from the earbuds at an angle actually give the headphones an interesting look. And the fact that the earbud housing angles the earbuds inward toward your ear canals also makes them look unique. These two design features have functional implications, which we’ll break down further in later sections.
One of the most maddening things when searching for Bluetooth earbuds is finding ones that have an adequate fit—it needs to feel both comfortable and secure. The Sennheiser HD1 meets both requirements, allowing for a comfortable workout headset that you can wear for hours without concern of ear fatigue. Like most other offerings, the HD1 come with a set of silicone eartips that get as big as about 0.5 inches each. There are four total eartips in the set, which is one more than many other Bluetooth headsets, so you have much more versatility in finding your ideal fit.
Also, because the driver housing turns inward, they angle in a way that should work for most people. We got our hands on a pair and spent a few days around NYC. Between commute music and workout beats, and we found this angle was the simplest, but most beneficial feature for a good fit. It’s important to note that this may be different for different users, depending on the specific angle of their ears.
The last factor to consider with comfort is weight. At 4.8 ounces (really closer to 4.7 ounces on our scales), these are among the lightest wireless Bluetooth headphones we tried. This is surprising considering how bulky the two remotes and electronics housings are, but that’s just a testament that this design choice wasn’t particularly necessary. Overall, the comfort on the HD1 gets a big thumbs up from us, but it’s important to note that your mileage may vary, and in smaller ear canals, these might not fit quite as securely.
The durability of the Sennheiser HD1 is a difficult category to pin down for us. When we pulled the HD1 Free out of the box, there was a degree of cheapness—or at least the appearance of cheapness. The bulky faux-leather cases had a finicky zipper that was frustrating when putting the earbuds away and taking them out. And the ultra-shiny, metallic finish on the plastic just emphasized that these headphones are plastic.
There’s just something about a rubbery matte finish that just feels more premium in earbuds like this. Even the remotes and plastic housings in the middle of the cables have cheap, overly clicky-feeling buttons. The cable itself is a bright spot with these headphones as it’s thicker than many of the others out there, and because it isn’t rounded, it doesn’t tangle quite as easily.
At 4.8 ounces (really closer to 4.7 ounces on our scales), these are among the lightest wireless Bluetooth headphones we tried.
An interesting design feature that bolsters the durability is that Sennheiser has affixed a small plastic loop to the edge of each earbud. It positions the cables outward, so if you tug on the wire it won’t rip out of the earbud as easily. It’s an interesting design feature we haven’t seen on virtually any other Bluetooth earbuds.
One drawback on the durability front is there doesn’t appear to be any level of water or sweat resistance—at least Sennheiser doesn’t advertise it. We used these at the gym and there seemed to be no cosmetic effects. That said, we only tested the earbuds at the gym for three or four days, so the jury is out on long-term damage. Overall, it seemed to be fine despite the somewhat cheap-feeling materials.
It was no surprise to us to see Sennheiser offering an impressive sonic response with their Bluetooth headphones. The brand is known for professional audio equipment. Refreshingly, there’s a lot of specificity on the Sennheiser website, no marketing jargon standing in for real, raw numbers.
First off, Sennheiser pegs the frequency response at 15Hz–22kHz, which is impressive for such small earbuds. For perspective, humans can only theoretically hear as low as 20 Hz and as high as 22 kHz (though for most, that range is even narrower), so this spectrum is fully covered with extra data outside the range for posterity. The playback sound level is about 8–10 dB, which felt just right in our book, considering the earbuds provide a decent seal and don’t need a heavy-handed volume. Second, the high-efficiency MEMS speakers are designed to offer great sound response in a compact form factor.
Finally, the codecs here were very impressive as Sennheiser not only offers the heavily lossy SBC and AAC profiles, but they’ve also built in Qualcomm’s impressive aptX. This means that the compression Bluetooth has to do to files to send them wirelessly will remove a smaller amount of quality on the end playback.
Sennheiser pegs the frequency response at 15Hz–22kHz, which is impressive for such small earbuds.
These high-end specs panned out in real-world performance. That secure fit we mentioned earlier proved extra-useful on the sound quality front because it provided decent sound isolation, even from the loud subway noise we contended with while commuting. Even the angle of the eartips, pointing directly toward our eardrum, seemed to offer directionality we haven’t seen in many other earbuds. This all amounted to a nice sound spread, listening to everything from podcasts to top 40 and beyond. The spectrum also felt natural, not succumbing to the bass-heavy emphasis of beats or the tinny qualities found in things like Apple EarPods. If sound quality is what you’re after, the HD1 are sure to please.
Sennheiser advertises about 6 hours of battery life for the HD1. Compared to the rest of the premium Bluetooth earbuds in the field, that is right on par. But what is most impressive is that you really get that full 6 hours. We even eked out an extra 10–15 minutes during testing. This is arguably one of the most important features that many consumers look for in a pair of earbuds, so it’s nice that you’ll get what you’re promised. The internal battery is a lithium polymer with 85 mAh of capacity, a spec also on-par with many other Bluetooth headphones out there.
While the battery life on a single charge is solid, we found that the time it takes to charge with the included micro USB cable was a tad longer than we would have liked. This isn’t a huge deal, but if you need to juice them up in a pinch before a run, or something, you won’t get fast-charging capabilities like over-ear offerings like the Sony WH-1000XM3. That said, If a reliable charge is high on your list, then these headphones are a good bet.
Something that isn’t talked about much anymore with Bluetooth headphones is stability and reliability in the connection. That’s probably because we just assume that Bluetooth technology has reached a point where it’s near perfect. But you’d be surprised just how many Bluetooth headphones are finicky, even ones that are at the premium end of the spectrum.
The Sennheiser HD1 are fortunately one of the better ones we’ve tested. In fact, they’re remarkably good in this field. In three full days of testing between subway rides and office listening, we only experienced one or two moments of minor Bluetooth interference. On paper, the HD1 are Bluetooth 4.2, meaning they’re almost as modern as most other headphones (the latest current standard is 5.0). They offer 10 meters of range (plenty for most applications), and the full suite of expected protocols, including A2DP 1.2, ACVRCP 1.4, HSP 1.2, and even HD voice.
We found the call quality on them to be particularly good, with plenty of stability even when around large groups of other Bluetooth devices. One minor gripe is turning on and off the device requires a press-and-hold on the main button that’s a little longer than we deem necessary. It leads to a lot of false presses and even a few instances where we mistakenly didn’t turn it off. But this is a minor point, one that is easy to forgive with such solid connectivity.
All that said, we were disappointed to see that Sennheiser’s sound control app was not available for these, or any other Bluetooth headphones, aside from their newest true wireless earbuds. Sennheiser claims they’ll update the app to accommodate other models, and because the sound quality of the HD1 is so solid right out of the box, this isn’t necessarily a deal-breaker. But it would have been nice to have some added app customization built-in.
One reason people so willingly shell out high price tags for offerings from Bose and Apple is because of the fit and finish. The Sennheiser HD1 have a lot to offer, but from a build quality standpoint, they leave a bit to be desired.
To be fair, you can often find a great deal on the HD1. As of this writing, they’re about $105 on Amazon. But their list price is $199.98, so it depends a lot on where you buy it from. Because the sound quality and connectivity are so impressive, if you can snag the HD1 for around $100, they’re well worth the price.
Apple AirPods: While these aren’t true competitors because there’s no wire to be seen on the AirPods, we had to mention these because they offer much more convenient connectivity and a nice-feeling package. That said, their sound quality can’t touch the Sennheisers.
Bose SoundSport: The Bose SoundSport are some of our favorite Bluetooth earbuds in this category. The fit and sound quality rival the Sennheisers, and the build quality is much better with Bose. But you can sometimes find a better deal with the HD1.
Sennheiser HD1 (headband version): For roughly the same price and a very similar feature set, you can opt for the headband version of the HD1 that lets a ring rest around your neck, giving you a safer fit if you’re worried the HD1 Frees are going to fall onto the ground.
Excellent sound quality and connectivity, held back by a cheap build.
The specs and our experience with the HD1 paints a clear picture. If you’re looking for sound quality and strong connectivity, you can’t really go wrong with the Sennheiser HD1 Free. But if you want something that looks, feels, and portrays fanciness, they leave a bit to be desired. If you can score a deal in the ballpark of $100, then we recommend you pull the trigger. Otherwise, consider other options.