I still have M3sis and they do have advantages ie type of sound which mostly can’t be gotten with sealed/ported box speakers.
Firstly the foam surrounding your drivers may have gone bad. You can inspect to see (I have directions somewhere how to take them apart).
You will need a more powerful amp. When I bought mine 30 years ago I was recommended a 75 W class A amp (worked well). Mine has several db more sensitivity so you’ll need more than that. Least 100-150W. High current solid state might be ideal. No clue about class D for this situation.
I’m sure you know these must be placed away from back wall, so hope you have a big room.
Firstly the foam surrounding your drivers may have gone bad. You can inspect to see (I have directions somewhere how to take them apart).
You will need a more powerful amp. When I bought mine 30 years ago I was recommended a 75 W class A amp (worked well). Mine has several db more sensitivity so you’ll need more than that. Least 100-150W. High current solid state might be ideal. No clue about class D for this situation.
I’m sure you know these must be placed away from back wall, so hope you have a big room.