Pros: A lot of bass, lightweight, very comfortable, cheap, easy to power.
Cons: Very recessed mids and highs relative to the bass, muddy sound, low overall sound quality with very little detail, short cable.
I bought these headphones just for the fun of it, to see how they sound with all that apparently amazing bass.
Well, for $50, they're ok sounding for extra bass headphones. They do have a lot of bass, but its not a high quality detailed bass, its that one-note boomy mess that makes
a boomy muddy messy veil over the rest of the sound frequencies. Compared to my 6 year old Sennheiser HD212pro, which was a headphone in the same price range back then as the XB500 is today, I'd say the HD212pro is considerably better in about every single way. While it doesn't have quite as much bass, it has about 90% of the bass quantity and higher bass quality, while the rest of the frequencies are much less recessed and much more detailed.
Also, the extension and punch of the bass on the XB500 doesn't seem to be great. For example, and this is going to sound crazy to some people, AKG K701 has much better bass extension. Bass on XB500 noticeably rolls off, regardless of amplifier used, and especially when used unamped out of some portable device. If I were to test both headphones at lets say 80 hz, and volume match them, then playing a 30 hz tone on both headphones would reveal that K701 stayed pretty much at the same volume level, while the volume on the XB500 dropped considerably.
Another thing is the punch of the bass. Again, even compared to so called "bass light" headphones such as K701, XB500 has less bass punch. It's just too slow and muddy to have any sharp and fast punchy impact. Listening to Infected Mushroom albums, its clear the K701 is in a different league when it comes to bass punch, so, for an "extra bass" headphone, XB500 doesn't really do that well. Well, it has a lot of bass quantity, but in a positive and negative way depending on the recording. Sometimes, the bass is ok, when the only thing in the track you're listening to is bass, and everything else is pushed back. If you listen to a bassy track that has a lot of other sounds going on in the mids and highs, its going to be a muddy mess.
Going from HD212 to XB500 on certain more congested track feels like you've added some pillows between the drivers and your ears that block all the sound except the bass, and still, there's not that much more bass on the XB500.
All in all, it gets a good mark for portability, lightness, comfort and a lot of bass, which is good if that's what you're looking for.
If you want a bassy headphone that does all genres well, look elsewhere. I mean, the clarity and detail of the mids and highs in the XB500 is on a level of earbuds that I got with my Samsung Galaxy phone.