Upgrade from martin 40i

Yes new tweeter really did help out the sound!!!

I have to say I’m very curious as to what the final result has been with your ML 40is.  
Did you get your new tweeter installed?  Did that solve your problem?  Thanks. 
 

@ramshackle The ML40i speaker is decent for Home Theater (HT) use. Worth fixing and replacing both of the Folded Motion® tweeters if they are affected. Call ML and ask about replacement. Best to check all connections at speaker and amp. It’s worth having the MRX 720 amp checked if you suspect a channel problem before playing the speakers again - - and before any tweeter replacement.

I agree look into fixing your MLs, especially if you like them and if it’s that easy. That aside, what improvements would you be looking for with new speakers if you go that route?

If you live in the northeast just go pick these up if they’re still available.  I’ve heard your speakers and these will stomp your MLs into the ground on every level. 
https://www.usaudiomart.com/details/649878811-joseph-audio-rm25si-signature-speakers-with-750-upgrade/

+1 @phasemonger 

Even if you want to upgrade, fix them first.

I know you're looking for new speakers, but here's some info if it's useful for you: I have ML 40i speakers and thought I had blown my tweeters. I called ML service and they sent new tweeters immediately, at no charge. It was an easy install, took about 20 minutes for both. Great service from ML. Best wishes!

Check out the KEF R11’s.

Ascend towers. https://www.enjoythemusic.com/magazine/equipment/0312/sierra_tower_speaker.htm

Monitor Audio