One thing I should also mention that the music also plays a big part in headphones comparison. Most of the newer music seems to be very limited in dynamic range and sounds really digital on all headphones. It's a shame really.
Does the Accudio app only work with local music files? Have they updated with iOS7 UI yet? I was waiting for them to update the app before buying it.
For testing I was trying out lossless tracks (with little d/r compression) and HDtracks (down sampled to 16/44). Rush, The Who, The Eagles, Type-O Negative, Opeth, Epica, KMFDM, C.C. Colette, various Chesky demos.
As for Accudio, although they update the list of headphones, they actual app seems to be locked into the drab original iPhone style. It's fully functional, but rather 'boring' compared to the sleek look opt iOS 7. The App itself uses both local files and files on storage, meaning it will play FLAC, and it will output full 24/96 if connected to a proper external DAC/amp (been eyeing a FiiO E17 myself) otherwise will resample down to 16/44. But hey, for $5, you can't go wrong because the balanced settings are worth it. D/L the free version (locked to 1 headphone choice but if you delete and re-d/l you can choose again) and give it a whirl.
Edited by Bansaku - 6/16/14 at 2:06pm