Hi guys I own a Philips Fidelio x1s. ... interesting in the price range up to $500 ...
Would these be good options?
Massdrop HD58X
Massdrop HD6xx
Hifiman HE400
I bought the Dan Clark Audio (not the Dave Clark Five) Aeon RT for $500 from their web site.
The
Aeon RT (or Aeon X from Drop) is a retuning of the original Mr Speakers Aeon headphones at nearly half price.
Give the Aeon RT a listen. I think you'll like 'em.
The Sennheiser 6xx will satisfy your music needs as long as you have a quiet room and roommates who don't mind hearing your music. The open back makes them loud to your roommates, and makes even quiet roommates interfere with your enjoyment of quiet passages in your music. With hi-end gear, the 6xx can sound like uber hi-end headphones. I was suprised how well they scaled, far more than their 58x brother.
The 58x are not as 'warm' as the 6xx. Still since there is low distortion the clarity is phenomenal in both sets, even though the 6xx does not emphasize the hi-end like some other brands (cough au revoir cough).
I have not heard the HiFiMan.
Dan Clark accepts return requests for headphones in like new condition for 15 days. The Aeon RT is a fantastic headphone that brings much of the TOTL sound at a unusally decent price for hi-end hifi gear. I think if you want a noticeable change the Aeon RT is the better choice since it's a planar whereas the Sennheisers are going to sound much closer to the Phillips you own.