Jaybird's X series has held a position among our favorite Bluetooth earphones for over five years now.
Priced identically to their predecessors at $129.99, the company's new X4 earphones bring some new tricks to the table.
The waterproof in-ears feature exclusive-to-Jaybird Comply Ultra foam eartips, redesigned interchangeable eartips and fins, and a new cable cinch management system.
If these sound like somewhat incremental upgrades, they are, but when your product is among the best, not every iteration needs to reinvent the wheel.
In terms of audio quality, Jaybird's free app offers customizable EQ, so you can lock in whatever sound signature you desire, from pounding bass to austere flat response.
The X4 earphones are incredibly versatile, and earn our Editors' Choice for exercise-focused in-ears.
Design
Available in black, glacier white, or jade, all X4 models feature metallic accents and can be worn over the ear, with the cable behind the neck, or with the cable dropping below the chin.
The built-in cinch clip means you can securely fasten the slack and not worry about cable thump ruining your listening experience.
There's also a shirt clip just in case things aren't quite secure enough.
The cable itself is flat like linguini and features an inline remote control and mic.
An IPX7 rating means the earphones are sweatproof and waterproof—they can be submerged up to one meter without issue, so they can definitely withstand heavy rain and being rinsed off after runs.
Jaybird includes three pairs of eartips (small, medium, and large), and you can make the argument that the inclusion of the Comply Ultra eartips negates the need for these at all, since the foam contracts and expands to fit most ear openings.
We suggest using the foam tips, even though the silicone eartips fit just fine.
The Comply foam will enhance your in-ear seal, and also boost the bass response somewhat.
All of these accessories, along with the included USB charging cable, fit inside an included black pouch.
The charging cable, it should be noted, is about as short as they come, and rather than connect to a micro USB port on the earphones, it uses a proprietary connection to snap onto the bottom of the inline remote control, so there are no rubber compartment lids to open or close.
The remote, located close to the right earpiece, is of the three-button variety, with a central multifunction button handling playback, call management, and voice assistance (it's also the power button when held in for a moment).
The plus and minus buttons handle both volume levels and track navigation—a design choice we're not huge fans of, as it's easy to accidentally skip a track when you mean to only adjust the volume.
The inline mic offers excellent intelligibility.
Using the Voice Memos app on an iPhone 6s, we found the sound quality excellent when the mic compartment was held away from the face or neck.
When the mic comes in closer, as it sometimes did in testing, the quality is still very clear, but there's the added noise of it bumping up against skin.
The free Jaybird app (for Android and iOS) provides user-customizable EQ settings, as well as presets.
As mentioned, if the Comply tips end up boosting the bass response too much for your tastes, you can always dial it back here and save the settings in the app.
Spotify users can also stream Spotify directly through the app.
Beyond this, there's a quirky feature that allows you to switch left and right channels (for those who want the remote on the other side), and a Find My Buds feature to locate lost earphones (this uses a small amount of extra battery life).
Speaking of battery life, Jaybird estimates it to be roughly eight hours, but your results will vary with your volume levels.
Performance
With the EQ set to flat, the earphones deliver a sound signature that still packs plenty of bass depth.
One note: Jaybird's idea of "flat" is our idea of "bass-forward." If you're really after a flat sound, we recommend going into the EQ, dialing the bass back a few notches, and adding in a small amount of high-mid response.
On tracks with intense sub-bass content, like The Knife's "Silent Shout," the earphones deliver the lows with gusto, and at top, unwise listening levels, they don't distort.
Boosting the bass here takes things to insane levels, but it can also be dialed back significantly.
Bill Callahan's "Drover," a track with far less deep bass in the mix, gives us a better sense of the X4's general sound signature.
In flat mode, the drums pack some added bass depth, but nothing over the top.
Callahan's baritone vocals get enough high-mid edge to retain some crispness, as does the acoustic guitar's strumming.
To our surprise, however, we didn't prefer flat mode.
Messing with the EQ allows for crisper highs and some better bass definition, as well.
We boosted the lows a little and the high-mids and highs slightly more, as the default flat setting is bass-leaning.
Even without boosting the bass, the earphones sounded better to us with a little more high-mid and high-frequency presence.
This will all come down not only to personal taste, but whether you're wearing the silicone eartips or the Comply tips, as we did for testing.
With the EQ back to flat on Jay-Z and Kanye West's "No Church in the Wild," the kick drum loop receives enough high-mid presence to retain its punchy attack, though typically we like to hear a little more high-mid action here.
But there's definitely some high-frequency presence, pushing the vinyl crackle and hiss forward in the mix.
The thump of the drum loop is powerful, and the sub-bass synth hits get plenty of extra push.
Going into the EQ and boosting the lows can take this track to crazy levels, if that's your thing, and you can also add in a little high-mids for better definition.
Orchestral tracks, like the opening scene from John Adams' The Gospel According to the Other Mary, receive some added bass depth that will irk purists, but again, you can always dial things back to normal levels in the app.
It's unclear why all manufacturers don't include a user-customizable EQ app at this point—if the earphone's drivers can deliver a wide range of sound, why not let the user adjust to taste? We applaud Jaybird for its decision here.
Conclusions
From an excellent in-ear fit and waterproof design to a user-friendly app that allows for a bass bonanza or a fairly accurate, flat sound signature, the Jaybird X4 earphones are a notable step forward in the series.
We test a lot of exercise-focused wireless in-ears, and these are definitely our favorite under $150, and thus our Editors' Choice.
That doesn't mean there isn't healthy competition, however: Consider the JBL Reflect Mini 2, the JLab Epic Sport Wireless, the Bose SoundSport Wireless, and JBL Reflect Fit if you want to shop the whole field.
The Bottom Line
The wireless, exercise-focused Jaybird X4 earphones are supremely versatile, delivering booming bass or balanced audio depending on your EQ preferences.
