I don't think the HD25 has enough resolution to make this distinction clear. I have some other phones where this would be much more pronounced; i.e., Beyer DT1350, Westone 4r or my ES5, ATH-ESW10JPN or the HD800. The HD25 is a fun headphone but not highly resolving in my opinion.
Since i have been travelling in Asia at the moment, only have the Sennheiser PXC450 with me, for the noise cancellation on flights, besides the newly purchased HD25. Have tried the DT1350 in the Japanese shop, But felt (at least at that moment) that HD25 sounded a bit better. Though the sound stage is quite narrow for HD25, which is the pitfall, but I mainly listen to vocals and pops...
Ps. Filter 2 is better than filter 1 when listening to pop, in my ears
Edited by yosment - 6/22/12 at 10:06am