Well, don't things get interesting when you change pads and driver covers around! My new Dekoni DT990 pads arrived today and, like the other nearly new pair (
https://www.ebay.com.au/itm/261338110308), came with a new set of driver covers/inner pads, as in these ones (
https://www.ebay.com.au/itm/Repacement-Ear-Pads-For-Beyerdynamic-DT440-DT770-DT790-DT797-DT880-Headphones/322344443901?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649). They are cheap as chips and actually came with everything advertised, the velcro strap and the cleaning cloth, unlike the other pair which did NOT have the accessories advertised.
I popped the new pads and inners on immediately, after warming up the Valhalla 2 and QP1R. Noticeably, the new inners are at least 50% thinner than the 'old' ones. I think the ear openings in the pads are a little smaller and tighter than the original stock and extremely comfortable pads, they're fine though. I like that the inners are thinner.
With both together, the sound has certainly changed. The really full and intimate solidity of the HD250 pleather pads has gone, to be replaced with a balance more like the original stock pads, but a little fuller in balance, no bad thing in my book anyway. Vocal focus tightened up and lightened in tone a little as well. Bass is NOT as focused and, disturbingly to me, has lost some pace and tautness, definitely not a fast and light as the stock pads, though certainly fuller and weightier in balance. I really love what the HD250 pleather pads bring to the table, though they
are a little darker in tonality. As I said, the Dekoni DT990 pads lighten that tone to nearer neutral, yet I wasn't really getting INTO the music in the same way. Diction is good, the wonderful work of art that is Alt-J's 'The Ballad Of John Hurt', from the All This Is Your's album, has many lengthened syllables and the pronunciation of the "s" at the end of "woooods' is easy to hear. The track lacked some pace though, not that's it's a fast piece, just that it seemed as if the whole recording speed had been slowed just a tad, I wasn't entranced, as I most certainly should be. Same for "Within" from Random Access Memories and with faster beats the bass lacked the sheer solid weight I am used to. With the HD250 pleather pads and their thicker inners, I am in love with the music, intimate, close, entranced. A little weird maybe, but there you go.
So, I have now decided that I am going to use the thinner new inner pads with the pleather ear pads and see what happens, I will keep you posted! I suspect a nearer perfect balance, but we shall see