I have owned my HSU VTF-15H & the MBM-12 MK2 for about 4 months now. I have spent a hand full of evenings trying different placement locations, bass crawling, adjusting, measuring, re-adjusting etc!!! I have been able to get my bass (16hz-250hz) with no more than 2dBs of variation. The results have been nothing short of AMAZING!!
I have a livingroom that is 2,500cuft but it opens up to approx another 4,500cuft. I have owned 6 previous subs from Sony, B&W, MartinLogan, Klipsch & Earthquake. With each purchase the bass was an upgrade for sure. But my last sub upgrade were these HSU subs & the leap in bass was huge!
With my speakers crossed over at about 90hz the MBM is handling 90-50hz (Nearfield) & the VTF-15H is handling 50hz & below (Farfield). I have the MBM in sealed mode & the 15H in MaxOutput mode Q .4. Both subs phase are set to 0.
I dont get any hint of delay whatsoever!! Im wondering if your Phase is set wrong. Ever room & placement is different so you need to try all 4 Phase options between the 2 subs. Have someone else flip the Phase switches while you set & listen. If possible, have an SPL meter in hand when you do this. Listen for the bass to be more powerful & smoother. Try each sub set to 0, both set to 180 & both options of them set opposite.
I have always been intrigued by the idea of splitting up the bass frequencies ever since i first read about it a few years ago. We do this for all the other frequencies by using tweeters, mid drivers & bass drivers so why not do it with sub-bass frequencies. I can personally vouch that 12" subs hit hard & clean but 15" subs dig deep. The combo of the MBM & a true sub of choice works so d@mn well i love it. Problem is however, that mow i want to save so i can get another MBM & another VTF-15H so i can have the MBMs in the back 2 corners & the 2 15Hs up front. Haha thatd be nice!!
For anyone considering the MBM-12, i personally recommend it very highly!!
Well done HSU!!