Question On Magnepan 3.7i and 3.7x Vocal Levels

I recently purchased some Maggie 3.7x models and have discovered an unusual issue with a lot of different recordings.  With many pop recordings like Beatles, Sting and Steely Dan, the vocal levels in the mix are lower than I hear on other speakers, including my Magnepan 1.7i, KEF LS5 and Vandersteen IIc.  Just to clarify, I’m not referring to imaging, but to the vocal volume levels relative to the rest of the mix.  With many of them the snare and guitar solos are louder than the singer.  On my other speakers and Sennheiser headphones, the vocals are considerably louder.  Hearing the same recordings on the 3.7x, it sounds like a completely different vocal mix, with the vocal track slightly in the background.  On other recordings like Nora Jones, Diane Krall and Julie London, the vocal levels are where they should be and sound amazing. 

I’ve tried positioning them with teeters in, tweeters out, different toeing angles, different distances from the front wall and side walls and different side-by-side distances, but nothing seems to help.  I just installed some GIK Polyfusers on the front wall for diffusion and while they really helped with imaging, they don’t help with the low level vocals. The best overall sound is with the speakers 4.5 feet from the front wall.  I spoke to Magnepan about this, but their response was that the 1.7i have a midrange bump, making the vocals louder than the 3.7x.  Has anyone else experienced this low vocals issue?

For reference, my system is all PS Audio, with an Airlens endpoint, original Direct Stream DAC, BHK preamp and BHK 250 amp.  Livewire speaker cables and DH Labs interconnects. I’m streaming with Tidal through Roon.