Hello
I spend some evening to try a solution to MUFFLE RINGING OVERTONES I have on several my drum.
Of course thicker skin help , but with this method You can get better sound and may be You are enough satisfied and avoid to change skin.
I have fix 2 strip of tin on the skin like picture, weight is about 3/4 grams each ,If weight is too much , muffle is too and You lose sound , I used electronic balance.
You have to combine weight , position , and lengt of these strips ; it need a little bit care but You can have good result.
I have got the best result with 2 strip like in the picture , but You can try also with a longer single strip.
This kind of tin is used to produce artistic glass and it have adhesive , but may be You can use glue.
I tryed also with plaster I have stolen to my daughter and may be result is a little better than tin ,but it is impossible to have a permanet fixing, see picture.
I tryed also with silicon , but is is too elastic , may be I will test other kind of gum.
Another intersting thing I discovered is that phisic of sound of drums is much much more complicated than I could think, please see this web site:
https://soundphysics.ius.edu/?page_id=1150or this experiments on Youtube:
https://www.youtube.com/watch?v=Zkox6niJ1WcSkin of drums do not have Harmonics but modes of vibration , the right balance of these give pleasant sound.
Saludos