I tried the HM5 pads over the ATH pleathers, but without the ports taped.....I would rather use Parametric EQ on the low end than tape the ports. I tried various combinations with taped ports, and just couldn't get it to sound natural.....I personally like the HM5 pads by themselves right away, but I did EQ 30hz up 2db to fill out the bass on the low end a little more.....then I devised the O rings to keep the HM5 pads on, still using +2db at 30hz. I can remember the first weeks with the S500, and having EQ's down 4db at 30hz, 60hz, and 125hz to keep the bass from messing with the mids and highs. That worked very well, but when burn in was complete, at about 400 - 500hrs the low end settled down and the rest of the spectrum opened up, eliminating the need for EQ. I can switch the EQ at 30hz with one mouse click, and for some music albums, there is still a need depending on the mastering. But when the album is mastered well, the bass can do what it wants without EQ, and I feel that I get a good balanced sound with single bass notes, no muddy booming, and clear/dynamic mids and highs. I think bass affects the rest of the sound spectrum more than any other aspect, and I like full single bass notes mixed with the music as long it is not overdone. I like my mids, and I don't care for the mids when bass gets too involved, and that happens when the midbass at 125hz gets too overpowing. To me that affects the clarity in the mids, and looking at a lot of frequency graphs you will see the there is sometimes an abundance of bass right there. Anyway my opionion, and each has there own preferences....this is just my take!