I dunno, its really hard to say if it's worth the upgrade. If you absolutely love the HD25 and all you want is an upgrade on the sound and a different cable size maybe, but maybe you are better off spending the money to get a different kind of sound and then you can work out what you prefer.
I like the Amperior more than the M80 myself.
I've tried the 598 but not for long and not directlyagainst the K550.
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Thank you very much for your reply lachlan. Yes i like the hd25 but of course they have their flaws and the most noticeble ones are the sometimes spikey highs (but this does not bother me much), the compressed sound (of course the amperior will not be much better in terms of soundstage...) and of course the grainy sound when compared with the momentums.
To get the amperiors i would have to sell my hd25s (i can get 100 euros for them) and add an extra 40 euros for the amperiors since they are being sold for 140 on the french amazon.
I can see that the highs and the grainy sound seems to have been improved on the amperior (i never tried them, only read about). Although there seems to be some flaws on the amperiors as well. The flimsy cord, and also the heavier weight (it also seems that the aluminium cups are more prone to damage and scratches).
Now what bugs me is that the hd25s are out and they seem to be a improvemente over the original 25s and the amperiors. Is it me or is sennheiser becoming a milking company and the hd25 seems to be their call of duty? :-D
Have you tried the hd25s alu already m8? If yes ur thoughts are more than welcome (specially a amperior vs aluminium comparison).
About the home headphone... I am thinking of getting the hd598 or the k550 because i am about to let my momentums go. I love them and their sound and resolution but while walking i loose the seal in a blink (i have 67mm ears ) and because of that i am mostly using them as a home headphone. although i like them, its stupid to keep a lifestyle headphone when the lifestyle purpose as been killed because of the seal.
As a mostly pop rock and edm listener i dont know if any of these 2 would fit my needs since they seem to be 2 laidback headphones and much more suitable for more calm styles.
My idea is to keep the hd25s or to buy the amperior as a portable/all rounder and as a more suitable option for agressive/fun styles like edm or rock and to have a open option with more spacious and laidback sound for home use and for more relaxed styles (some pop or indie and stuff likejames blake).
Since most people here on head fi say the hd598s and the k550s are a league ahead of the momentums in terms of sq thats why í thought of the as home use options.
If u have other sugestions please share them...