does one have an idea regarding the difference between the two in reference to sound ?
Unequalized, the se535 sound like $20 earbuds compared to my JH16s. I would imagine the Roxanne to be an even wider gap. The se535 can really redeem itself if you boost the lows and the highs, but out of the box there is no comparison at all.
Also,to answer a previous question, a headphone out with the lowest impedance possible will achieve an appropriate frequency response across the spectrum. In general, the higher the output impedance, the more the highs frequencies will be attenuated. It's best to maintain an impedance ratio between output and load of 1:8, which in the case of the Roxanne's, means your output impedance should be under 2 ohms for best performance.