==== Summary ====
The Jaybird X4 earphones blew me away with its quality build, supreme comfort, and excellent audio quality. It does so many things right - light & durable, super comfortable in the ears, water resistant, excellent control over sound through the custom EQ app, great audio, and long battery life. Athletes will love the Jaybird X4 as well as casual users who value sound quality and water resistance flexibility. Jaybird has lived up to the hype and has created a very good and compelling product. These are fantastic earphones.
**Pros:
-Light and comfortable design.
-Secure fit with soft ear fins/hooks.
-Both the silicone & Comply foam ear tips are comfortable.
-Comfly foam ear tips provide great natural/passive sound isolation.
-Fantastic audio quality (with in-app EQ adjustment).
-Good phone call quality.
-Excellent battery life.
-Earphone control buttons work well.
-Excellent Jaybird app (custom EQ, battery status, Find my buds).
-IPX7 water resistance.
-Quick charge.
-Tangle-resistant cord.
-Cord cinch is useful.
**Cons:
-Very short (~3") & propriety charge cradle cable with no wall charger.
==== Design & Comfort ====
The Jaybird X4 earphones are designed very well - for both athletes and casual earphone users. It is light, made with durable materials and quality plastic, very comfortable for extended usage during normal & physical activities, and come with both soft silicone and Comply foam ear tips (in different sizes).
Between the two types of ear tips, I prefer the Comply foam tips (size small). They are more comfortable to wear and they also offer better passive sound isolation than the silicone ones. In addition, sound quality gets a boost, especially in bass-heavy songs.
The ear fins come in two different sizes as well and they're soft and compliant and fit inside the ears snugly and securely. I'm a jogger and the X4 was an excellent running companion with its secure fitment, outside noise isolation, and comfort. During my usual 5 to 6 miles run, I sweat profusely so it was good to know that the X4 is IP7X water resistant. I also appreciate being able to quickly clean the earphones with water without fear of damaging them.
The Jaybird X4 is controlled with a 3-button remote module located near the right earpiece - volume up, volume down, and the middle multi-function button. The middle button is used for Power On, Power Off, Bluetooth pairing, answering/ending phone calls, and launching Google Assistant (with my Samsung Galaxy S9+). Everything worked smoothly and perfectly.
The X4's battery is replenished by a charge cradle with a cable. One side of the charge cradle snaps onto the body of the remote module of the X4 and you then plug the other end of the cable into a charger or device that accepts USB Type A. I successfully charged the X4 by plugging it in to my laptop, my desktop PC, and one of my smartphone chargers.
It took a little while for me to get used to snapping on the charge cradle to the X4. It was kind of annoying trying to align the pins on the charge cradle to the remote module despite the four small guiding tabs on the charge cradle that help with the alignment. I'm sure muscle memory will kick in soon, though, and the process will become easier and faster through time and repetition.
With that said, I prefer this charge cradle method over having to using my fingernail to pull back a rubber or plastic flap before inserting a charging cable. I believe Jaybird is using this method to meet its water resistance and durability requirements.
All in all, Jaybird has created some awesome hardware with lots of thoughtful and useful features. 10 out of 10 from me~!
==== Sound Quality =====
Out of the box, I found the sound to be just so-so though it was still better than my other two wired Bluetooth earphones - some $30 earphones from Amazon and a $100 JLab earphones. Once I opened the Jaybird app and played around with the EQ settings, however, the sound quality became FANTASTIC and AWESOME. I started with the "Warmth" preset profile and made sound quality my own by adjusting the Low, Mid, and High ranges within the "Customize" option.
After saving & applying my custom preset, my enjoyment of music from the Jaybird X4 went from a 7 to 10 out of 10. I highly recommend everyone to invest some time and play around inside the EQ settings to tailor the music to one's personal tastes. It really does make a HUGE difference.
I am not what you call an audiophile but the X4 - after EQ tuning - has really impressed me with its sound quality. The sound is crisp and clear, the bass is pretty decent (for Bluetooth earphones), sound separation and dynamic range are well-presented, and it delivers very well-balanced audio. I love it.
Is it as good or better than over-the-ear headphones such as the Sony 1000XM3 or Bose QC35 Series II? Of course not. But for wired Bluetooth earphones that offer easy portability, lightness, and durability during physical activities, I don't think one can do better than the Jaybird X4.
10 out of 10~!
==== Battery life ====
The X4 offers very good battery life. 8 to 9 hours of playtime is higher than most other similar competing products and you won't have to charge it midday like you do with those small wire-free Bluetooth earphones.
10 out of 10.
==== Conclusion ====
Jaybird has created an excellent product in the Jaybird X4. It is stylish, light, well-built, super comfortable, durable, easy to use, and provides fantastic sound quality. The icing on the cake is its IPX7 water resistance and long battery life. For anyone that asks me to recommend a good pair of wireless Bluetooth earphones, I'll tell them to get the Jaybird X4. It is some good stuff.