@Hasse
There is no frequency response spec. from Magnepan on the 3.7, just a range!
Which is meaningless!!!
You need a measurement with +/- dB.
The older models also state "minimum average in a typical room".
Jim Winey was more of a "fanatic" than his son Mark, I have met them both.
I live in Saint Paul, and know people that use to work at Magnepan. It is a nice very small, family operation. They are good honest people.
Why did Mark Winey refuse to submit the 3.7 to stereophile for testing, saying the the frequency response was proprietary? LOL! Because it sucks for a speaker priced close to $6,000! That's Why!
Do not argue!
Just rent a professional, calibrated SPL meter, use the Stereophile test CDs, and find out for yourself! If you want them setup right, in your own room, that is necessary! I own both the IIIa and 3.6 and have done that, in several rooms. I have done a quick check with a hand held RTA on the 3.7 in different rooms, and they do not go as low.
As far as the 3.7 suggested better "COHERENCE" goes. What is that??? And how do you measure that???? Every Magnepan from 1970 on is "coherent", and I have heard most of them.
IMO Magnepan reached the end, with the previous models. Now the reviewers bring up "problems" with the old models (that they never mentioned before) to make the new ones appear better and increase sales! It is an old trick! And it has been repeated by every audio company and reviewer forever.
If you like the 3.7 that's fine, good for you.