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


First time Magnepan owner - 5  days old 100+ burn-in hours on them
Associated Equipment:
-Denafrips Terminator Plus
-Holo Audio May KTE version
-Pass Labs X22 Pre-amp
-PrimaLuna EVO 400 Pre-amp
-Pass Labs XA100.8 Monos
-PrimaLuna EVO 400 Monos
-AntiCables interconnects and speaker cables
-Stock tweeter attenuator jumper replaced with AntiCables level 5 spade jumpers on the 1.7i's

My spectrum analyzer indicates both speakers highs are falling off beginning at 1.25K and are 9db down from 2.5K on
Been playing around with speaker placement and room treatments for 2 days now without any remediation. What am I missing? Suggestions appreciated.
128x128nayls02

dekay
3,770 posts
07-29-2021 9:10pm
Suspect that they are not propely hooked up/connected.

If damaged it's unusual that both speakers would have the same fault.

Not a clue as to what the "add-ons" mentioned by the OP are, but suggest hooking them up stock (nasty jumper plate and all).

I responded to another Maggie owner here with similar complaints and the HF problem was resolved with proper hookup (poor electrical contact was the culprit I think, but too lazy to look back through my posts).

DeKay


~~~~~~~~~~~~~~~~~


I aint buying in.
No evidence his hookups are faulty.

I reiterate: The tweeters in OP's speakers are either working properly or they are not.  And nobody here knows what other variables/factors are present in OP's situation. Not every problem nail needs a sledgehammer. (HUH? whatever does that mean?)

I suspect that @dekay  is on the right track.  

I will say it's (sorta) fun to read all the responses in this thread.  But I think it's time for me to unfollow. Best wishes and I hope OP gets it sorted out.
mozartfan would you put a cork in it?

ONCE again read before you post..

I offered a reasonable solution it see if the tweeter section is playing and if it is, let it break in.

Second a di pole will comb filter like no other it will cancel out front to rear because of the common pole.

PUT a pillow over the back of the tweeter section to stop the combing,. IF that works you know it’s combing. NOW position the speaker to reduce the combing as much as you can.. The -9db should go down. 

You can double check for combing by using only a single speaker, pull it to the center of the room..

TWO ears TWO eyes, ONE mouth... Order away, they are great speakers..

Regards
1.7i's sound like they have a head cold because of where the inductor is placed in the crossover. 

If you don't want to mess with the insides, the easy solution is to buy a Shiit Loki or Lokius and bump the frequency you are not hearing properly. I bought one as an amusement and not only does it do that well, but you can also bump the bass, as they will produce a significant amount more than their stock configuration. Same concept as a plate amp for subs. Box subs don't go that low naturally, their bass is intentionally overdriven. Not talking about open baffle or horn subs, just boxed ones.

Let the naysayers descend like rabid wild animals while they mic measure their rooms and let a computer do the tampering for them, all feeling safe on the streets knowing there are no tone controls on their preamps.

Everything else that offers a significant performance increase is major surgery that requires removing the panty hose, starting with a million staples.