Beside sparse info on the newer cone materials I havent seen any comment on the new d48. Im in the waiting for my studio 148 so I have been through lots of forum in french and english talking about proacs and cant remember a single comment for d48. People who own them must be pretty happy.
Carbon have been dropped from the studio line for paper and reworked in "pulp/carbon fibers"??? for the response line. I think it has to do with with how carbon has hard to control peaks in upper mids and is hard to fine tune. But please dont spread my words, im guessing here. But I have been confirmed that the studio line sounds better and can only assume the response line too. I was in a position were I could not audition without taking a weekend trip so I just ordered. I know its a bad practice but I didnt have time for this. You may well have to take the plunge too assuming you like the response line already.