I haven't measured anything so I may just be getting used to the headphones or indeed be placebo I guess. To me the difference is there, but it isn't the difference between Grado and Sennheiser. It is a slight shift, it feels more open to me. But more doesn't mean a ton, just not the same. I look forward to reading your findings on the mods too. My ears are probably more tuned to where bass guitar, synth and drums sit in the mix, how they kick and attack. I played in bands for over 20 years. With ear protection throughout I add. Hehe.