I got my AKG K 702 with the Cardas 10' Fat Pipe cable yesterday. It's got the same essence of my Etymotic ER-4PT with the 4S adapter, but the sound stage dimensions are much larger and the treble does not roll off at 16 kHz. These are extremely high resolution and detail retrieval is second to none in its class. They are extremely neutral and accurate.
Regarding my MP3 collection, I have to eat my words and I have to say that I can now tell the clear differences between 320 Kbps MP3s and FLAC when comparing the same bit depth and sampling frequency. FLAC has a crisper sound that is more accurate, but it's not a decisive win for FLAC or other loss less codecs. FLAC and WAV sound crisper and clearer with no audible artifacts or limitations imposed by the ageing MP3 codec. For high resolution 24 bit 192 kHz FLAC files, it's simply no contest: FLAC sounds much better than MP3 at high resolutions period.
I'm still keeping my very large MP3 library because it's extremely convenient and it's a universal format. I think that I'm going to restore my huge FLAC library from my CrashPlan+ account this weekend.
MP3 is showing its age. LAME 3.9.9 --preset-insane 320 Kbps MP3 does have minor yet audible artifacts and it does roll off the treble at 16 kHz. For the majority of music, this is not so much of a problem with ordinary audio components.
I have an exceptional home audio system and desktop PC. I'm also the lead singer in my church choir so I have to understand pitch and accuracy. I think that the MP3 codec is not going away anytime soon, but I now strongly prefer Vorbis especially using the Ogg container. To my ears, -v10 at 500 Kbps bit rate Vorbis is indistinguishable from WAV or FLAC loss less codecs. The file sizes are still huge when encoding using these loss less codecs or at the top bit rate for Vorbis, but that's life. This is why I have 18 TB of USB 3 external hard disk drives.
I have a mint pair of Wilson Audio Alexandria XLF floor standing loudspeakers and MP3 sounds compressed and lossy through them. They sound compressed and lossy through my AKG K702 with the Cardas Fat Pipe cable. It's just that they are extremely convenience and the file sizes are bearable especially for portable gear that makes it very difficult for me to switch back to FLAC.
C'est la vie!