My New Magnepan 1.7i's sound dull and lifeless on the top end...why?

Hi Friends, 

So I am at about 250 or so hours with my new 1.7i's, and also experiencing the lack of highs, and sort of lifeless sound as well. Do they ever open up more, after more hours...or is this it?  🤔  They are quite slow sounding, and I have a McIntosh MC 252 driving them, on its 4 ohm Taps.  So weird. I'm  not used to Maggies sounding slow, as I've owned MG 12's in the past, along with. 5's, and these sound nothing like those.  So will these open more in time? Did the original post guy have any changes to his?  Really curious, and also wondering if I should start driving them hard and loud to get em to open shop.  Just don't know.  Thanks for any insight.  -Brian.

Did the original post guy have any changes to his? 

Yes, he had pushed the banana plug in too far and it was contacting elements. Your issue may be different. I didn't like my Mac 402 with my .7 Maggies. Much better with a Parasound A21 and a lively preamp. 

OP, this will answer some questions:

I’ve been a loyal Maggie owner for decades using 10s, 1.6s and 3.6s as my main speakers. I even bi-amped my 3.6s using a Pass Labs XVR -1 crossover. I moved on to YG Acoustics and couldn’t be happier. The YG’s are more accurate, neutral, detailed and musical.

I have no affiliation with GR, but found the video and measurements to be informative.

Okay, little update here...and this is for MY particular ROOM.  I think I've solved my situation, and posting in case it helps any of you.  I have a small room, and had the tweeters on the inside all this time, figuring it was the best plan with my little space. WRONG BRIAN!!!  I moved them to the outer edges, with slightly more toe in, and the difference is NOT subtle!!  Beautiful highs, openness, and imaging.  Plus it spread the music on a wider stage, with no loss of excellent imaging.  It's actually more focused in a real stage way, and as it was with my previous set ups. I'm now pretty damned happy, as set up the other way, they sounded like they were playing in their cardboard boxes!!!  So there you have it.  Your room may vary, but try what I did if issues, and remember to tow em in well. Ahhhh.  Back to Maggie May Bliss!