Mass Loaded Vinyl (MLV) Acoustic Treatments - A Question

MLV comes in different thicknesses, from thin drapes to sheets inches thick

At this point in time - I have installed a vinyl roller blind that is very effective at preventing reflections and because it is installed at the ceiling-wall boundary, also traps/disperses reflections there - a bonus!

But unfortunately it is not effective are preventing the very low frequency "bass blooming" I am currently experiencing.

From what I have read, my room is the ideal size for the propagation of low frequency standing waves- 11.5' x 15' x 8'(high) 

So I was wondering if anyone out there had used the thicker versions of MLV in order to curb bass related issues and if so - what thickness did you find effective and how did you install it?

My system resides in my Living Room, so I am trying to "limit the visibility" of any device I install, either by design or concealment.

Many Thanks