The Fidelio L1s pair well with all types of music, as you should expect from $300 headphones. There's sweetness to the sound balance, a mild richness that I found attractive, specifically when listening to acoustic sounds. The natural stereo imaging doesn't suffer the empty balance that I get with overly closed-back headphones.
To put the sound balance in perspective, I compared the Fidelio L1 headphones with Bowers & Wilkins' P5 over-ear headphones, listening to ZZ Top's "Fandango" album. Both sets of headphones handle hard rock with ease, which means they sound great with the music turned up nice and loud, but the Fidelio L1s open with more detail and richer bass response, lending more gravitas to the music than the P5s can muster.
Paired with Abel Korzeniowski's orchestral score for the soundtrack to "A Single Man," the Fidelio L1s sounded more spacious while the P5s presented the same music with a closer perspective. Which is correct? I can't say for sure, but the Fidelio L1s' clarity and natural appeal are indelible.
Up to this point, all my listening impressions were made with the Fidelio L1 headphones plugged into a simple iPod Classic, but at home I switched over to a USB digital-to-analog converter/headphone amplifier ($140) running off my Mac Mini computer and found the Fidelio L1s' sound was deeply enhanced, with even more powerful bass definition. Soft-to-loud dynamics also saw improvement, which is what I usually hear when stepping up from portable sound sources to a good home headphone amplifier.
The Fidelio L1s' big soundstage is suitable for movies to the point that the sound seemed to come from the screen after listening for just a few minutes.
The Philips Fidelio L1 headphones' performance, build quality, and comfort place them in the top ranks of $300 full-size headphones. For the price, the Fidelio L1s far outclass most competing sets in terms of build refinement and sound, and I recommend this model to anyone looking for a boost in audio hardware.