Last year, I bought a Fiio E7 to drive my 64Ω Sennheiser cans from FLAC / AIFF sources. This year, I bought one of the new Haswell-based MacBook Pros, and haven't missed the FLAC file support all that much. The reason I bought the rMBP was to start producing some of my own content (videos, voiceovers, and a podcast.)
I am looking for a new set of open-back headphones that have a wider range and high impedance. I am NOT looking to change source, DAC, or amplifier at this time. I want to buy a set of headphones that match the capabilities of my existing hardware, without shooting long and paying for a level of quality that I won't realize with my $80 16/48 amplifier. My main complaint with my existing closed-back headphones are low impedance and muddled high/low ranges.
I am also unclear on the theory behind impedance-matching. The Fiio E7 is rated for headphones up to 300Ω. But I have also heard that one should use a ratio of 1:8 for determining maximum impedance. The other option is for me to spend $80 extra on a Fiio E9, which is rated to 600Ω. But then that means I will have to spend $80 less on the phones themselves :-/
I would prefer not to buy Sennheiser again, but will consider all other options. I am probably limited to a max price of $199, but I am very willing to consider a lightly-used set of open-back headphones in that price range as well.
Any recommendations :)