If you don't mind an open backed headphone then I would look at an OPPO PM-2 and the Musical Fidelity V90-HPA:...
I like the Sennheiser headsets:
OK great! Let me know what you think :)
I heard them at CanJam in London - very impressed :)
I'll second that on the OPPO HA-2 - the best portable amp/DAC solution I have come across with amazing value! :)
I think the V-Moda Crossfade Wireless could be the one for you!
We don't stock it at the moment but I would highly recommend it for what you are...
FiiO do some great amp/DACs - these two will connect to your computer by USB and they will improve clarity and power:
FiiO E10K Olympus 2
Have a look at these models:
Audio Technica AD900X
They all tick the boxes you have mentioned :)
Here's our TV Headphones Guide for 2015 - covering wired, wireless, analogue and digital headphones.
There's something for everyone :)
An amp could improve the sound for you but I'm not sure how much of a difference it will make. The X5 shouldn't have a problem with...
What about the Sennheiser HD25 or Beyerdynamic Custom One Pro?...
I think that the AKG K77 is a closer match to the K99.
This might help:
I would recommend these:
I'm afraid that I haven't heard all of those models. Here is what I would recommend:...
You can't go wrong with the Sennheiser wireless range:
I would go for the OPPO PM-3:...
There are a number of different ways you can do this, personally I would go for a new player that can handle hi-res audio and then some...
I like the Beyerdynamic Custom One Pro:...
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