Help me understand how to optimize bass on the Zu Definition Mk IV

I am a longtime owner of Zu Definition Mk1.5 speakers and recently also bought a pair of Definition Mk4's. I based this decision partly on the reviews / feedback posted here on Audiogon in various threads by members such as 213cobra, gsm18439, spiritofmusic and others. I'm really hoping some of you Mk4 owners can chime in and help me out here!

Basically, my issue is that I found the Mk1.5's put out incredibly deep and impactful bass, especially with some of the music I love, like R&B and reggae. And this was with the bass amplitude knob at 12 or 1 o'clock. However, after setting up my new Mk4's, I find the bass underwhelming and anemic, even after fiddling around with various settings and with the volume and PEQ cranked. I have them on spikes into bases on a hardwood floor, with about a 1.5" gap on the bottom. What am I missing here?? Based on the reviews I read, I was expected the bass to equal or exceed the lowly 1.5's. 

Thanks so much in advance for any helpful advice! 

Yeah, I'm not too interested in spending much on power cords etc. at this point. I was just interested in the grounding posts you had installed on the Zu's and your overall power management scheme, as I've struggled with some hum and slight buzz in my system. I do have the subs on the speakers on a different circuit, which I realize is an issue, but was more practical given how things are arranged in my listening room. Also, I misspoke when I said the ground loop hums are coming out the tweeter... obviously they are oscillating at 60hz. I actually only have a small amount of 60hz hum present in the FRDs and not audible in the sweet spot. I do, however, have some hiss and buzz out of the tweeter when the phono is selected on my turntable. I was able to reduce the buzz significantly by running a ground wire from the lamp above my turntable (on a dimmer, which is a likely source of the problem) to the turntable itself and then to the preamp. I had considered a star grounding scheme for the whole rig, which worked wonderfully to lower the overall noise floor when I did this for the analog mixing setup in my home recording studio. In such a configuration with grounding posts on the speakers, I could then lift the grounds on all but one of the components for a single path.
Request ground posts for Sean when he looks at yr amp modules.

I'm sure you'll like the Gaias footers, some mileage there.

The other thing to say David is that eight 10" woofers versus two 12" was always going to present a difference, esp rear facing versus down firing.

I think you need to approach the 4 as a different spkr to the 1.5, blank canvas approach on set up.
Very true, Marc, I'll start from square one with setup once the amps are back. I really appreciate all the help you and Phil have given me here. David
My pleasure David, I hope it helps. I've been masochistically flying the Zu flag for 6 long years on What's Best Forum, mainly receiving brickbats in return LOL - so, its great to try and help by conversing with a fan of the brand.

Certainly I'm sure Sean and Phil can bang their heads together and get you in the right direction.

Be patient. I have been, for 11 years now LOL.
If I can get detailed answers to the questions I raised a few posts back, I might have more suggestions. -Phil