Review: JBL Synchros S700 Headphones Tested with Beastie Boys

Electronics GeekMom

Over the past couple months, I’ve had the chance to check out the top of JBL’s newest line of headphones: the Synchros series. With Synchros, JBL is promising a set of high-quality headphones featuring their JBL PureBass sound quality, with the higher-end models featuring JBL’s new patent-pending LiveStage signal processing capability.

I received the JBL Synchros S700 headphones at the end of last year. Family members and I have been using them throughout the house to test its comfort, sound quality, and rechargeability. I was able to compare these headphones with other full-sized over-the-ear headphones, such as the Able Planet Clear Harmony model I had reviewed in 2012, as well as Beats by Dr. Dre Solo headphones. We are very pleased with these headphones, although the price tag (MSRP $349.99) might be off-putting for many. However, if you are a fan of bass in your music, this is the investment for you.

The Synchros S700 sets itself apart from the other Synchros models in that it’s rechargeable. The headphones have a built-in Li-ion battery that will provide the LiveStage signal processing for up to 28 hours of continuous listening. Read on for my impressions of the S700.

What Comes in the Box 

  • Synchros S700 headphones with built-in Li-ion battery
  • Faux-suede clamshell zippered carrying case with velvet interior
  • USB charging cable
  • Universal headphone cable with multi-function controls
  • iOS-specific headphone cable with multi-function controls

The Power Button: What Does it Do?
They’re headphones, so things are pretty straightforward. Put them on and enjoy! Unlike the Beats Solo headphones I used for comparison, you can listen with these headphones without hitting the power switch.

The power button—to turn on the LiveStage signal processing—on these headphones is quietly embedded on the left ear cup. Just depress the round panel with the letters “JBL” until you hear the long solid beep.

The little white light will illuminate when the headphones are powered on. Photo: Patricia Vollmer.
The little white light will illuminate when the headphones are powered on. Photo: Patricia Vollmer.

The sound capabilities on these headphones probably won’t make much of a different to a lay-user. But I broke out some of my more serious GeekMom-Headphone-Test music to see what’s so special about this particular pair.

My music of choice for this is Beastie Boys. The album is called The Mix Up. The song of choice is titled “Electric Worm.” It’s full of bass. Without the power on, the low pedal tones are sitting in the background…as if it were an afterthought. But when you depress that “JBL” button, the difference is profound! This is not noise-cancelling going on; this is an explosion of bass that will transform the way you listen to your bass-y music.

I did a side-by-side test with this song on the S700s, the Clear Harmony, and the Beats Solo headphones. While everything else about the sound quality between the three was comparable, the S700s will “pull” the bass out significantly better. In fact, this CNET reviewer claims that the S700’s bass is superior to that of the Beats Pro headphones, that company’s highest-end model.

Save the Battery Life. Really.
Unfortunately, most of what I use headphones for does not involve such bass. Therefore, if you’re using these headphones to watch Downton Abbey on without bothering your husband who’s watching Archer in the same room, the LiveStage capability isn’t really going to make a difference.

Speaking of batteries, I have had these headphones in my possession for 2.5 months and still haven’t had the batteries run out on me. I’m sure I’ve had them on for more than 28 hours (the advertised battery lifetime), but I probably only remembered to turn on the power to the headphones about half the time.

If you do hear the low-battery warning beeps, it’s easy to plug the headphones into your nearest USB port for easy charging. I was able to get charging to occur both on my laptop and with a USB-to-A/C adapter. I can’t speak for how long it takes to reach full charge on the headphones, because I haven’t run out of battery yet to take that measurement.

It's in the details. Easy-to-maneuver hinges, aircraft aluminum trim makes these more professional-level. Photo: Patricia Vollmer.
It’s in the details. Easy-to-maneuver hinges and aircraft aluminum trim makes these more professional-level. Photo: Patricia Vollmer.

No Skimping on Luxury
The fine details to these headphones set it apart from other over-the-ear headphones with comparable sound quality. The super-soft real leather ear cups have made these headphones a pleasure to wear for long periods of time. The lightweight aluminum headpiece and trim makes for a sleek, modern design that seems classier than Beats plastic molding on each of their models, except the “Pro.”

The aluminum headpiece has a cushion on the underside for comfort. Photo: Patricia Vollmer.
The aircraft aluminum headpiece has a cushion on the underside for comfort. Photo: Patricia Vollmer.

Cable Troubles
The S700 comes with two headphone cables: One for iOS devices and the other for “all others.” Both cables worked perfectly well for their purposes. We tested them on the following devices: iPhone, iPad, iPod shuffle, MacBook Pro computer, Kindle Fire, Samsung Galaxy Note 8.0, and a Dell Zino PC computer. I did the main audio quality testing with my MacBook Pro.

I had numerous concerns with the cable. For starters, it’s shorter than other headphone cables I’ve experienced for higher-priced headphones. At only 50 inches, it’s over a foot shorter than the Able Planet Clear Harmony cable.

Both cables have multi-function buttons on it that allow you to control your music, but on the S700, the controls are rather high-up on the cable, in approximately the same location as on Apple earbuds. Therefore, you can’t see which buttons you’re pressing. You will need to learn by touch which are which.

Finally, as is the case with all high-performance headphones with completely-removable cables, you need to be sure to firmly plug in the cable at both ends. On the S700, this isn’t as obvious as one might think. This caused me some issue last month, when I was excitedly beginning an episode of Sherlock on and didn’t realize one end wasn’t seated all the way. I had the background music, but no dialogue.

Going Soft on the Case
I was very surprised that such expensive, high-quality headphones had a soft-sided case. I do know that comparable models of over-the-ear headphones (Beats Pro, Bose QuietComfort 15) include more rigid cases. I think JBL should rethink this product’s case.

These are very high-end headphones, meant for the true audiophile, sound engineer, and DJ. If you look at the Beats by Dr. Dre “Pro” model, you’ll see similar audio capabilities, design features, and pricing. The sound quality on the Synchros S700 is very good and even with my “layman’s” ears, I could tell the bass qualities are top notch.

However, if you’re like me, listening to music most often when working out or binge watching Doctor Who and Walking Dead episodes in the same room as her sons playing with Lego bricks…well, it probably won’t make a difference.

If you know someone who has discriminating tastes in their audio equipment, the Synchros S700 headphones would make a great gift. If you think you or your loved one doesn’t need such capability, JBL’s full Synchros line includes numerous models of headphones and earbuds to fit every budget and useage choice.

JBL Synchros S700 headphones retail for $349.99 and can be found online at or other electronics retailers, such as Amazon. You can also check out the entire Synchros line here.

GeekMom received this item for review purposes.

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3 thoughts on “Review: JBL Synchros S700 Headphones Tested with Beastie Boys

  1. Hello. I enjoyed your review and you inspired me to buy it. Right now I have a rather stressful issue I can’t seem to find an answer too. When the LiveStage is turned on even though the headphones are not connected to any sound source I hear a constant white noise – static. Is this normal? Does your headphones make the same noise or should it be as quiet as they are with the live stage turned off?

    Thank you

  2. To Daniel I also have a pair of S700 it only makes that sound when I have the Livestage on and headphones are connected to my Toshiba laptop (Laptop may have issues)but on my Xperia phone its all okay even if Livestage is on or off. you can isolate the issue by turning on Livestage without the cable to check if its the headphones or cable issue.

    Over all its great I can’t see any headphones within the same price bracket that will match its sound quality and technology.

    1. Thank you Stingray for your reply. On my Lg G2 it’s better – less noticeable but still I can here something. With Livestarge on and without the cable I can still hear a white noise like on my Lg. My question for you: without the cable and with Livestage on can you here a sound or are they perfectly silent?

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