Magnepan 3.5r Owners needed.... No bass

Hello.  Brand new to the site.  I have been into Magnepans for years. 

I have 3.5r speakers which are wonderful.  

But lately it sounds like they have little to no bass.  I have them bi-wired, and when only playing the bass, it is barely there.  Strange because these used to have loads of clean, tight bass.  The mids and the highs still sound spectacular.  No buzzing, no problems.  I've examined them in bright sunlight and there is no delamination on the wires or anything.  Ive taken apart the crossover and measured and it all measures to the correct values according to the schematic.  Why would my Mg12's have loads more bass than my 3.5r's?    Powerful amplifiers.  What sound I do get is beautiful.  But just not getting the bass that this speaker should put out.  

Wondering if anyone with these speakers has experienced this issue.  3.5 or 3.6?  

Any help would be appreciated.  Thanks.