I have a pair of 30 year old Maggie IIIa's and a pair of new 3.7I's and have to agree that the newer Maggies took hundreds (300-500) of hours to break in. Until they broke in, the soundstage was diffuse, and the bass was less than stellar. Honestly they were a mess until breaking in.
The new speakers definitely added a strip of felt behind part of the midrange. My guess is that it is to dampen the back wave reflection and allow the speaker to be placed closer to the FW, thus making the speaker more spouse friendly. It is obvious when looking at a 3.7 vs a 3.7i. Magnepan is famously reluctant to give details though.
One tip with the i series is that they need -- according to Wendell -- to have the woofer panel slightly closer than the ribbon tweeter. This of course means that if your tweets are in that you need a lot of toe in, possibly more than you are used to. Less toe in with tweets out. You can see the effect of getting the tweets further away in measurements as it mostly reduces a suck out around the crossover which is readily apparent if the tweets are the same or closer.
I have not heard the 3.6, but compared to the IIIa, the 3.7i has more detail, has a much smoother and tamer upper midrange, more upper bass and substantially less low bass. The older speakers go down to the upper twenties while the new ones end in the upper thirties. (In the 30 years of evolution they made the woofer panels smaller and the midrange larger).
i am currently running both pairs. The 3.7i's are being run in my smaller room with Pass 250.5 amplification and are about 7.5 feet from the FW, tweets in lots of toe in. I am running the older pair in a much larger room tweets out, about the same distance from the FW, with DWMs to boost the mid bass. I drive the second pair with the 1700 watts into 2 ohm Emotiva XPA1s (the DWMs and larger room make the tough Maggie load tougher).
I prefer the Pass Labs and 3.7i, but there are pros and cons to both systems.
The new speakers definitely added a strip of felt behind part of the midrange. My guess is that it is to dampen the back wave reflection and allow the speaker to be placed closer to the FW, thus making the speaker more spouse friendly. It is obvious when looking at a 3.7 vs a 3.7i. Magnepan is famously reluctant to give details though.
One tip with the i series is that they need -- according to Wendell -- to have the woofer panel slightly closer than the ribbon tweeter. This of course means that if your tweets are in that you need a lot of toe in, possibly more than you are used to. Less toe in with tweets out. You can see the effect of getting the tweets further away in measurements as it mostly reduces a suck out around the crossover which is readily apparent if the tweets are the same or closer.
I have not heard the 3.6, but compared to the IIIa, the 3.7i has more detail, has a much smoother and tamer upper midrange, more upper bass and substantially less low bass. The older speakers go down to the upper twenties while the new ones end in the upper thirties. (In the 30 years of evolution they made the woofer panels smaller and the midrange larger).
i am currently running both pairs. The 3.7i's are being run in my smaller room with Pass 250.5 amplification and are about 7.5 feet from the FW, tweets in lots of toe in. I am running the older pair in a much larger room tweets out, about the same distance from the FW, with DWMs to boost the mid bass. I drive the second pair with the 1700 watts into 2 ohm Emotiva XPA1s (the DWMs and larger room make the tough Maggie load tougher).
I prefer the Pass Labs and 3.7i, but there are pros and cons to both systems.