natureboy,
As stewart0722 mentioned, the 2.5/R are older speakers circa 1987. They have a freq. range of 37-40,000 hz +/- 3 db. A big plus of these spkrs is that they have the very good true ribbon tweeter panel section, not the QR (Quasi-ribbon) tweeter panel section used in some other Maggies.
Here's my opinion of the sound quality performance heirarchy of Magnepan spkrs I think you're considering (from best to least in sound quality performance):
1. 3.7i - Circa 2014, $5,995/pr.
2. 3.7/R -Circa 2011, $5,495/pr.
3. 3.6/R -Circa 2000, $ used/pr.?
4. 2.5/R- Circa 1987 $ used/pr.?
5. 1.7i- Circa 2014 $1,995/pr.
These rankings are just my opinion and others may disagree. I'm not going to go into great detail to explain my rankings or the differences between the models.
I also want to add that I've auditioned all of these, with the only exceptions being the "i" versions, at audio stores only and not in my system/room.
I ranked the 1.7 and 3.7 "i" versions superior to the base models of each based on their overwhelmingly opinions of the "i" versions superiority by professional audio reviewers and my own opinion that Magnepan would not have added these versions unless they were convinced that both were significant improvements.
I believe the 2.5/R is likely the best value of the bunch since it has the excellent true ribbon tweeter section and would be the least expensive. The 3.6, 3.7 and 3.7i, in my opinion, are going to be clearly superior to the 2.5 but I believe the most noticeable difference will be the improvement in bass performance which is significantly more effective on the 3.6 and above. Used or demo versions of 3.6/R and 3.7/R may also represent bargains.
If you have a local Magnepan dealer, you should visit and audition some of these for yourself. The dealer may even allow you to home demo some.
Thanks,
Tim
