Howard Leight Sync Stereo Review: Noise Blocking Earmuffs with Integrated Headphones

In this review I am reporting on my test of the Howard Leight Sync Stereo Earmuffs.

Unlike other industrial earmuffs, these have built-in headphone speakers and a 3.5 mm audio jack, allowing the wearer to listen to audio while working in a high-noise environment, e.g., with power tools. Read on to find out how they performed under 90+ dB noise.

I am also going to use them to block office and coffee-shop noise, and noise travelers are typically exposed to. Speech and other varying-state noise have been shown to negatively affect the performance of students and office workers alike. I am hoping that these earmuffs might also provide a budget option for cognitive workers suffering from the noise in their environment.

Review of the Howard Leight Sync Stereo Earmuffs


Noise Blocking

The Howard Leight Sync Stereo are solid earmuffs with a noise reduction rating (NRR) of 25 dB (ANSI S 3.19-1974). This standard is mandated by the EPA when labeling hearing protectors in the U.S.

They have also been tested according to European standard EN 352-2:2002 and rated with an SNR of 31 dB. The 6 dB difference is due to a different testing standard and a different calculation method.

In terms of their noise attenuation, the Howard Leight Sync Stereo earmuffs are comparable with the 3M Peltor Optime 98 and the Howard Leight Leighting L1.

Sync Stereo, NRR 25         
Frequency (Hz)125250500100020003150400063008000
Mean attenuation (dB)19.122.428.731.736.83939.439.441.4
Standard deviation3.
Optime 98, NRR 25         
Frequency (Hz)125250500100020003150400063008000
Mean attenuation (dB)15.52233.739.736.542.740.139.840.6
Standard deviation2.

The Sync Stereo perform better at the low frequencies while the Optime 98 are better in the mid-frequency range.

Running power tools and listening to music

I tested this with a circular saw, cutting steel at 94 dBA and an angle grinder at 93 dBA, grinding steel outdoors.

Wearing the Sync Stereo, I was perfectly able to listen to Pink Floyd and audio books at a moderate volume.

I also tried other tools and machinery at up to 97 dBA while listening to an interview podcast and had no issues understanding the speakers.


Obviously, no hearing protectors will silence noise this loud. But with these I can protecting my hearing while still being able to listen to audio.

For even higher noise environments and to create more silence, I wished Howard Leight would produce a Sync Stereo model with an NRR of 30 dB.

The closest I have found are the NRR-30 Impact Pro earmuffs, which have speakers and an audio input jack. The Howard Leight Impact Pro are available in two models, one for shooting and one for industrial noise.

They feature electronics and a microphone to emphasize environmental noise while clipping dangerous noise levels. Unfortunately the volume of the environmental noise amplifier and the audio input are regulated through the same volume control, so when turning up the music volume, you also hear more of the environment.

I contacted Honeywell (the parent company of Howard Leight) as to the speaker performance when using the Impact Pro in off-mode. They said the Impact Pro would work, but that external devices generally do not deliver enough power.

Instead, they recommend getting the Sync Stereo earmuffs for streaming music. So while the Impact Pro are stronger earmuffs, their electronics and speakers are designed for amplifying environmental sounds (e.g., for communication and hearing environmental noise when hunting).

Blocking speech and office noise

Good voice blocking is hard to achieve with noise isolation (passive) alone.

At present, active noise cancelling (with electronics) is even worse for this purpose. It does not work for a large frequency range important for speech blocking, so noise cancelling headphones also rely on noise isolation for muffling higher frequencies.

Because they feature very good noise isolation, the Howard Leight Sync Stereo block speech, crying babies, clicking keyboards, etc. better than my Bose noise cancelling headphones. The Bose block low frequency noise such as rumbling traffic, air conditioner humming, and the bass portion of sound systems better.

That being said, the Sync earmuffs’ noise isolation alone is not enough to render louder speech unintelligible. They also won’t completely get rid of screaming.

However, when playing white noise (’s white noise generator) through the muffs, I can block almost all office and coffee-shop noise, including people talking next to me.

For this purpose, these muffs are among the best budget solutions I have found so far.


In the picture above, I am trying the earmuffs at a coffee booth in a large shopping mall. The booth is somewhat shielded from the mall with glass dividers, but it is not a separate room. They were holding a tombola outside and the promoter was using a PA system. The noise level was 72 dBA with peaks of more than 80 dB.

Playing white noise, I was well-shielded from the buzzing mall. Even listening to acoustic guitar at a very moderate volume felt just fine.

My favorite NRR-30 earmuffs are better at blocking noises you typically encounter in an office, in a student dorm, or on an airplane than the Sync Stereo. The problem with my NRR-30 muffs is: they don’t feature speakers, and they make me look like I am about to unpack a jack hammer.

I have used earbuds underneath passive earmuffs, and in terms of noise blocking this works great.

The Sync Stereo are more comfortable than the earmuff-earbud combination and they look very sleek. Most people wouldn’t even suspect they might be earmuffs. And, they work very well together with white noise to mask noise.

If, however, as much silence as possible is the main objective, earmuffs with an NRR of 30 or 31 are still the way to go.

Traveling and airplane noise

The Sync Stereo earmuffs significantly reduce traffic noise and airplane noise. I walked around with them along noisy streets playing all kinds of music and white noise.  Listening at a normal volume, I was able to completely mask traffic noise, apart from low-frequency rumbling and occasional sirens.

This is great when travelling on public transport, but not recommended at all when navigating or operating a vehicle in traffic!

My Bose noise cancelling headphones block rumbling trucks and turbines significantly better and they are a lot more comfortable, but they also cost more than 10 times as much.

So all in all these earmuffs a great budget option for travelers.

Fit and Comfort

These earmuff headphones fit me well, but they shouldn’t be much smaller. They are adjustable, but like many other Howard Leight muffs, much less so than the 3M Peltor Optime series.

Adjusting the headband

For comparison, at maximum extension I can barely squeeze my index finger between the headband and my head while the index finger plus the middle finger fit between the Optime headband and my head.

The ear cushions seem to be the same as the ones used in the Howard Leight Leighting L3 (NRR 30), while the ear cup itself is a lot flatter.

For earmuffs the Sync Stereo are comfortable; I can easily wear them for a couple of hours, but have to make adjustments from time to time. Because they need to reliably seal the ear, they put a lot more pressure on the ear cups than headphones.

So no, they are not nearly as comfortable as Bose headphones, and I still prefer the Bose during a long intercontinental flight.

Wearing Sync earmuffs outdoors at 30+ degrees Celsius (86 Fahrenheit), my ears become sweaty pretty fast. This is a major disadvantage of all earmuffs and most over-the-ear headphones. I wish they made somewhat better ventilated ones, but so far I haven’t found any.

Sound Quality

Most people will get these earmuff headphones because they can block noise while listening to music or podcasts at the same time.

In my opinion, the Howard Leight Sync Stereo live up to that promise.

I have listened with them for hours to all kinds of music and podcasts, and I find the sound perfectly adequate for the money.

The highs are very detailed. Compared to the mids, they are overemphasized, which makes voices sound a bit nasal. They lack the low bass (the one that makes you feel sick at the movies). Normal bass is there, but could be a bit stronger as well.

Overall, I find them pleasant to listen to.

Do they sound like $100 headphones or $300 noise cancelling headphones? Of course not.

But they are good earmuffs that make it possible to listen to music and audio books under harsh conditions that would normally be prohibitive.

I also find them great for listening in moderately noisy environments like busy coffee shops, airports, and train stations.

Because of the excellent noise isolation, the music seems to come out of nowhere. I can listen at a very moderate volume and still notice the details. After a while, you feel like you are in your own world.

Other Data



Using the Sync Stereo wireless and making phone calls

I use the Sync Stereo together with the Loop R8, a tiny Bluetooth receiver you can clip to your shirt. The Loop R8 has controls for volume, pausing and skipping tracks, and receiving phone calls. It also features a microphone. Walking down a busy road, the call quality is fine, according to the people I have spoken to on the phone. The Loop R8’s battery is rechargeable and lasts me for a whole day.

Going wireless also solves the problem of the missing headphone jack on newer iPhones and Android phones.


Howard Leight has recently introduced the Sync Wireless, a Bluetooth version of the Sync Stereo with a boom microphone that seems to allow for phone calls even under very noisy conditions. I have not yet had the chance to try the Bluetooth version.

Double Protection with Earplugs

These earmuffs work fine with foam earplugs. I have tried them with the 3M 1100 underneath. The National Institute of Occupational Safety and Health (NIOSH) strongly recommends double protection for noise levels over 100 dbA.

Listening to music with earplugs underneath is no fun anymore though. Everything sounds muffled.

What can make sense is playing white noise to mask the remainder of a drill next door when you want to take an afternoon nap.


I like these earmuff headphones, especially considering how much bang you get for your buck.

The Howard Leight Sync Stereo are industrial-grade noise blocking earmuffs with an NRR of 25.

Unlike most passive earmuffs, they have built-in speakers and a 3.5 mm audio jack. The headphones need no battery.

For earmuffs they are comfortable, but due to the higher clamping force, they are not as comfortable as over-the-head headphones.  Like other earmuffs they get hot and sweaty when working outdoors in the summer.

They work well for listening to music, audio books, or podcasts while working under high-noise conditions. The main application is noise isolation/hearing protection + listening: I wouldn’t get these to replace good headphones in a quiet environment.

By the same token, stronger earmuffs are available for less if the focus is on hearing protection only.

They can be made wireless through a Bluetooth receiver and thus also be used for making phone calls. A wireless version with built-in Bluetooth is also available.

They are also a good budget option for students, office workers, and travelers that want noise isolation from the environment to focus on their studies or work while listening to music or using white noise. Good noise cancelling headphones are more comfortable and sound better, but cost several times what these cost.

13 thoughts on “Howard Leight Sync Stereo Review: Noise Blocking Earmuffs with Integrated Headphones”

    • Hello Laura,

      I actually have several favorite NRR-30 earmuffs, depending on the use case and wearer.

      The most effective ones I own are the 3M Peltor X5A (NRR 31). They are big and somewhat heavy, but great muffs.
      The 3M Peltor Optime 105 (NRR 30) are lighter, a bit smaller, and a bit more comfortable. The X5A block more noise, but the difference isn’t large.

      Both are durable general-purpose earmuffs and both have well-designed headbands that are adjustable for a large range of different head sizes.

      As I mentioned in the post, unlike the Howard Leight Sync Stereo, they don’t have built-in speakers.

      I plan to put up a post comparing different options in the near future, so stay tuned.

      All the best.

  1. Thanks for your article! It was very useful for me!

    Would you advise me to buy 3M Peltor X5A or the Howard Leight Sync stereo + white noise in order to cover the voices while I’m studying? I’m a college student and would like to study without constant voice noises and screaming.

    • Hi Stefania,

      thank you for the feedback.

      It depends on your preferred use case.

      If you prefer mostly not to have white noise either, the Peltor X5A reduce noise substantially better.

      However, If the chatter (or screaming) is close or loud enough even the X5A (which I like a lot) might not be enough, and you would need white noise as well.

      You can add flat sleep headphone speakers underneath the X5A and play white noise. In my experience, this is a lot more comfortable than using earbuds and it works well.

      With white noise, the Sync Stereo will work about equally well. The white noise would have to be a bit louder but the Sync Stereo are still good NRR-25 earmuffs. What’s more, you will have the added benefit of a decent sound quality for listening to music.

      So X5A: great noise isolation if you mostly don’t want any noise plus the option to play white noise via added speakers to get rid of the rest of the chatter.
      Sync Stereo: good voice blocking when used with white noise plus the option to use them as decent headphones.

      Have a great day.

  2. Helmut, Help! I work in a law office, I sit in the reception area, our conference room is right next to the reception area. The conference room has two regular walls, the back wall is a window and the front wall is separated glass with a glass door. I can hear everyone talking, and if someone has a loud voice, I might as well be sitting in there because I can hear everything.
    What can I get to block out voices, I do not want to listen to music?

    • Hello Wendy,

      that would annoy the heck out of me too and my performance would tank.

      It would be a good idea to better soundproof that conference room for increased speech privacy.
      There are certainly confidential meetings taking place that shouldn’t be overheard by people coming into the reception area. Have you tried talking to your boss about this?

      As to a personalized solution, the questions are “How loud is that speech at your workstation?” and “Are you allowed to acoustically isolate yourself from your environment?”

      Above a certain loudness, no hearing protector and no noise cancelling headphones will completely block speech. We also hear through our skull.

      At some point, you need to mask what still reaches your inner ear with sound.
      This doesn’t have to be music. It can be speech-masking-optimized white noise, rain sounds, or waterfall sounds. If you block as much as possible first, the sound doesn’t even have to be loud.

      The Howard Leight Sync Stereo are actually a very decent budget solution allowing you to combine noise isolation with noise masking.

      I have recently written a post detailing several other effective solutions for blocking speech and office noise, some more discrete than others.

      Please take a look. You are more than welcome to shoot me another message with more details in the comments there.

  3. Hello Helmut, the vertical dimension from the top of my head to the underside of the bottom of my ears is about 170mm. Please could you tell me what the corresponding dimension is in mm for the sync stereo 1030111 ear defenders in your review when extended to the maximum so I can be sure they will fit me. I have found some comments from other people that say they are too small.
    Thank you in advance. Martian.

    • Hello Martian,
      I measured 176 mm, stretched out over a headphone case. The Howard Leight Sync Stereo are a bit on the small side. They fit me but there is not much room left. When I turn my head to the side, they sometimes don’t seal properly.
      The thing is that the measured length will vary somewhat depending on how wide a wearer’s head is.
      For a friend of mine they are perfect.
      Their main advantage is that they are very light (and usually priced very economically).
      See whether you can return them if they don’t work for you.

      Just for comparison: the Worktunes Connect work well for me and the Worktunes Connect + AM/FM are huge. They would just fall off my head when fully extended.

      All the best.

  4. Hello Helmut, thank you for your fast response. You say “I measured 176 mm, stretched out over a headphone case”. Please could you tell me how far apart the ear muffs were when stretched over the headphone case. My head is 150mm wide and the vertical dimension from the bottom of the ear openings up to the underside
    of the headband on my comfortable ear defenders is 171mm. Thanks again, Martian.

  5. Hi Helmut,

    First of all I looove your site. I have hyperacusis and it’s very hard for me to find good earplugs/earmuffs. Foam earplugs irritate my ears, the X5A are too bulky to wear outside, and the X4A are very uncomfortable (I have big ears).

    So what would be a lightweight solution for me to wear outside with normal traffic/noise (70-80dB). I like earmuffs because I can get them off when I walk in parks or quiet streets. Currently I am wearing the X4A, but I dislike them a lot. I feel the X5A are a lot more comfortable.

    Would Howard Leight be a solution? I will use them only in passive mode. Any sound near my ear causes pain.

    Thank you

    • Hello Taw,

      Since you don’t need speakers, the Peltor Sport Bull’s Eye come to mind.
      They have the same NRR (27) as the X4A but a lot larger ear cup openings. You can even buy approved gel ear pads for them if you need even more space for the ears. But I would try them with the standard ear pads first. They are slightly heavier than the X4A but not bulky. I think they look cool.
      Take a look at my study earmuffs review.

      Alternatively, the X2A (very light) have substantially larger openings than the X4A but the same headband.

      If you want to try Howard Leight muffs, the Leightning L2 (also NRR 27) are an option. The ear cup openings are wider than that of the X4A. But note, the headband can’t be extended as much, so the L2 (as well as the Sync) are not ideal for large heads.
      Let me know how it goes.


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