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Whether you go in for the S200i (for Apple devices) or the S200a (for Android devices), you're in for a good time. These JBL in-ears sound great, and are durable and comfortable to boot.

While a little pricier than some of the competition, they're a smart investment if you're looking for a notably balanced sound backed up by durable materials.
The JBL Synchros S200i (MSRP $129.95) cost a lot more than the average, run-of-the-mill in-ear headphones, but they deliver a high quality sound. We tested a balanced frequency response with no problematic over- or under-emphasis of notes. As in-ear style headphones, these JBLs are also great isolators, blocking plenty of noise from the outside world. The only drawback I found was a lack of volume balance between the left and right channels, though the error wasn't enough to dock a ton of points.

Sleek, durable, and portable

The JBL Synchros S200i in-ears—available in black or white—look and feel like they were constructed with care. The cable is wrapped in a durable rubber that's been flattened slightly, which helps it lay straight and resist tangling. The jack is quite sturdy as well, but the real prize is the construction of the speaker backs, which are a handsome set of molded spokes—like a bicycle.

The JBL Synchros S200i speaker backs

The most interesting thing about the S200i in-ears is their spoke-shaped speaker backs.

The S200i in-ears come with small, medium, and large silicone sleeves, as well as a pair of Comply foam tips.

For in-ears, they're fairly comfortable, and the sizing options mean most people should be able to find a good fit. JBL also throws in a small, circular storage pouch with one of the most discreet zippers I've ever seen.

Along the cable, users will find an adjustable shirt clip and a three-button remote with nicely textured buttons. The Y-split can be adjusted as well, and is guarded by heavy rubber. I'm not sure everyone will go for the slightly aggressive look of the bicycle spokes, but there's no arguing that these JBLs have a unique look and a sturdy build.

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Testing revealed that the JBL Synchros S200i roughly follow an ELC (equal loudness contour), giving a little more emphasis to sub-bass and bass elements. These JBLs place sub-bass from 20Hz to 60Hz around 82-84dB, and bass elements from 60Hz to 300Hz around 85 dB. Compare that to middle frequencies around 1kHz, where volume begins to drop closer to 74 dB. This difference in volume is a good thing, as the human ear hears certain frequencies with more ease than others.

The JBL Synchros S200i roughly follow an equal loudness contour, allocating balanced emphasis to all frequencies.

The JBL S200i in-ears tested with a very well-balanced sound, giving solid bass emphasis while still supporting the middle and treble frequencies during playback.

When we compare the frequency response to an ELC, we can see why there are dips in emphasis around 2.5kHz and 7kHz. Because we're naturally more sensitive to those frequencies than to sub-bass, bass, and certain middle frequencies, lowering the volume of treble frequencies actually helps to balance out the overall sound of the music being played, giving each frequency its due.

The JBL Synchros S200i roughly follow an equal loudness contour.

These JBLs roughly follow an equal loudness contour, which helps to balance volume between sounds at different frequencies.

THD (total harmonic distortion)—sometimes just called distortion—refers to the presence of unwanted or clipped sounds in audio playback, often created by sub-optimal mechanical elements in the speakers themselves. The JBL S200i in-ears tested with almost no distortion whatsoever, maxing at about 2.5% within the sub-bass range. A THD of 3% or less is imperceptible to human ears, so listen as hard as you like—you won't hear any distorted or clipped sounds.

Don't listen as loud as you like, though. While the S200i remain distortion free until a volume of 117.776 dB, you shouldn't be listening that loud anyway.

The JBL Synchros S200i exhibit a very low amount of distortion across the entire frequency range.

These JBLs produce less than 3% total harmonic distortion across the entire frequency range—a great result.

Save for one small flaw, the S200i in-ears tested perfectly.

The JBL S200i in-ear headphones carry a higher price tag than average—they deliver great sound. Testing revealed a balance of emphasis for the entire frequency range. As consumer headphones go, the S200i deliver healthy bass support without neglecting the middle or treble ranges.

The S200i deliver healthy bass support without neglecting the middle or treble range.

I listened to a number of CD-quality tracks, everything from Andres Segovia to Daft Punk, and even some recordings I mixed myself. The test results were confirmed.

Bass and low middle sounds stand out prominently, but aren't treated to an overabundance of emphasis. Segovia's infamous rolled chords and glissando slides sound well-preserved, and even the string noise from the original vinyl recording sounds through. Electronic drums with stunning snare hits still pack a punch, but not enough to make you flinch. If you're into a flat, studio sound or majorly boosted bass, you may not love these in-ears, but otherwise there are absolutely no flaws in terms of emphasis.

With the right fit, the S200i block plenty of ambient noise, and leak none of their own.

With the right fit, these JBLs block plenty of ambient noise, too—and leak none of their own. The only place where the S200i in-ears could have performed better was in terms of balancing volume between the left and right speakers—they tend to favor the right channel, giving it more volume than the left. While this issue isn't obvious during most music, you might notice it during subtler content like solo performances or podcasts. That said, this is the only performance flaw we found.
Our tracking test charts the balance of volume between the left and right speaker channels. This is one place where the S200i in-ears could have performed a little better—they tend to favor the right channel just a little more than the left for most of the frequency range. While it's only a 2-3 dB difference, it could be noticeable during some content like podcasts.

The JBL Synchros S200i tend to favor the right channel over the left during playback.

The S200i in-ear headphones exhibited some tracking errors during testing, tending to favor the right channel during much of the frequency range, though only by 2 or 3 dB.

The gold standard

The JBL Synchros S200i headphones (MSRP $129.95) are at the top of the charts where in-ears are concerned. The sound they deliver is balanced and full, providing plenty of bass for low-end lovers, but making sure listeners with their heads in the clouds can still hear all of the highs. From thumping timpanis to trilling trumpets—and everything in between—the S200 headphones deliver.

The only drawback? For some, $130 is a little on the pricey side. Fortunately, JBL worked to justify the price by also employing a smart design and high-quality materials. Take a little care, and your S200i in-ears will look good and sound great for a long time.

Meet the tester

Lee Neikirk

Lee Neikirk

Editor, Home Theater


Lee has been Reviewed's point person for most television and home theater products since 2012. Lee received Level II certification in TV calibration from the Imaging Science Foundation in 2013. As Editor of the Home Theater vertical, Lee oversees reviews of TVs, monitors, soundbars, and Bluetooth speakers. He also reviews headphones, and has a background in music performance.

See all of Lee Neikirk's reviews

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