Hello all
This is my first post here.
The HD 25 1 ii has been my primary portable headphone for 10 years. I have tried many other headphones but always find myself returning to the HD 25 for portability, sound quality and ruggedness.
Last week I bought the HD 26 Pro and to my ears, they are definitely a step up in sound quality. I find them to sound at least as detailed but less in your face. Somehow Sennheiser has managed to retain the dynamic and clear sound quality of the HD 25's while cleaning up some graininess and peakiness, making the HD 26 Pro sound cleaner, more spacious and relaxed.
I don't think the HD 26 Pro is quite as indestructibly built as the HD 25 (time will tell) and I prefer the angled plug on the HD 25 cable for portable use. In all other areas I think the HD 26 Pro improves on the already excellent HD 25:
Comfort and isolation is better because of the softer ear pads, the cable is more flexible and transmits much less mechanical noise and the sound quality is improved and less fatiguing.