Excellent--I think I have enough of those panels to create a block similar to two LENRD'S together, and use it as a bass absorber IF I can effectively increase the absorption surface area and mass even larger by adding some extra mineral wool here and there.
It's good to know I can use some materials I already have. This is for future plans. Eventually I'd like to treat: my small very non-pro home studio/lesson room, the super tiny lesson room at the academy where I teach (the more ghetto stuff is going there, LOL!), and treat my living room a bit (long-term project as my plans right now include a lot of furniture-making, etc.).