I purchased the XX's about a week ago, so I've had time to fiddle with them for a while. Let's just jump right in with the sound. Unequalized, these sound like you're listening to a set of desktop speakers through a piece of wood. Not great. It's very muffled. But, the bass is very present, even the sub bass. Hence, the "Xtreme Xplosives" moniker. However, once properly equalized, they open up quite a bit. There is a slightly airy feeling about them, as if the sound is trying to break out of the earcups, but again, they still have a muffled veil stopping them. It's strange. They aren't entirely open or muffled, just somewhere in between. However, when paired up to a FiiO E11, highs become more piercing, bass shows more presence, they become more alive. This is with the EQ setting to max. They become very fun to listen to, but not for long periods of time. The clamping force on these bad boys is quite much, especially if you have a wider head like I do. The worst part about the headphones, honestly, is the construction. 100% PLASTIC. The only visible metal are the screws that hold the headband together. And speaking of the headband, after just 2 days of indoor use the headband won't stay fully retracted. The weight of the earcups pulls the right side headband adjuster down about 6 clicks. Good job, JVC Quality Control Department. 2 DAYS. Anyway, moving on. I purchased them at Marshalls, a discount retail store here in the southern states. I gave a big $20 for them. I didn't know what exactly to expect. I had previously owned a set of XX earbuds, and I loved them. They were like Sony XB500 in-ears. After about 3 hours of burn in, I finally started listening to them, and a week later, you now have my review.
TL;DR Version: Plastic $20 headphones that need equalization to sound decent and may or may not lose headband adjustment after a weekend.