Philips Fidelio L2 delivers some impressive sound. There's a great deal of layering and separation going on, and you ought to be able to distinguish and pin-point vocals, or instruments playing simulatenously. There's also an absolute joy listening to tracks that make proper use of stereo imaging, like Dead can Dance's Into the Labyrinth.
However, that doesn't mean the signature is completely neutral. Whilst it doesn't create some ridiculous U-Curve, it does peak around the bass and towards the higher frequency. It is a bit more accentuated and vibrant than the Senheiser Momentum, or even the original L1, but not as much as the V-Moda M100.
This means that if you are looking for a flat, accurate response from a portable pair of cans, the Momentum might be a better choice. However, you should keep in mind that it doesn't actually match the L2 in terms of sound-stage and spatialization.
Well, the bass is slightly (just slightly) accentuated, but it never feels boomy or bloated. It still is very tight and controlled, much more than on the original L1. Alas, with the low-emphasis, some hi-fi enthusiasts might not find the extra kick enjoyable.
The bass transitions nicely into mids, which are well balanced, with what seems to be an emphasis towards the upper-mid / low treble. This lends itself to a bit more presence in the vocals, which is always welcome. Otherwise, the mids are overall clear, smooth, though slightly on the warm side.
Treble is also nuanced, though it rarely becomes harsh. Cymbals are splashier compared to the L1, and the entire treble feels a lot more airy and crisp. The treble is by far the most enjoyable part of these cans, and it sounds as something you'd expect from much, much larger hi-fi cans.
My experience with the L1 is limited. Whilst I enjoyed its sound, I cannot say I was ever blown away. L2 is, however, a different story. First, these headphones aren't necessarily the best of the best, I mean they might rock your socks, but they won't make 'em run away too. With that being said, they do have a genuinely impressive sound-stage, one better than anything I have listened to in recent memory.
It's wide, it's deep, and the stereo imaging is great. I don't know what to say about it otherwise.
Gaming was more of a personal experiment than anything else. I don't usually mix gaming headsets with music cans, unless said cans can say something in a gaming scenario. The L2 are decent, though I cannot say they are great. The bass doesn't have the proper kick behind it, so it doesn't manage to give the right feedback in games like Battlefield or Counter Strike. With that being said, there's one quality that shines in gaming.
The deep and wide sound-stage, as well as the fantastic stereo imaging, lends itself to some great audio accuracy. If you ever relied on sound whilst playing a game, hearing someone creep up behind you, or pin-point the exact location of a gun-firing, then Fidelio L2 will work great wor you. There are many headsets that give you that powerful feedback, but don't actually manage to actually provide you with any kind of competitive edge while playing.
For mobile use, the L2 also has an inline microphone. These tend to be average at best, but most of the time they're atrocious. Not here, though. This is probably one of the best microphones you would find on a portable headphone pair. It picks up a bit more environmental noise than the smartphone mic, but other than that, it's pretty much the same.