I need bass

Davey??? We lost Davey.....

The great thing about speakers are: they don't know what type of music they're playing.  They either show you how the music/movie was recorded, or they add or take away from what you're hearing in the recording.  Does a voice sound like a voice - then it's probably right. 

Speakers are an instrument much like a piano or guitar.  The electronics are who is playing the instrument.  Some instruments don't sound good with the musician playing it.  Hand a Taylor guitar to Jeff Beck, Eddie Van Halen, Eric Clapton, Chet Atkins, you're going to get four different sounds out of it, but someone is going to make that guitar sing and sound right.  The instrument may have the tone you like, but the electronics can change the perspective.  But again, the system doesn't know what type of music it's playing.  The human voice is the one instrument everyone is an expert on and I say listen to that and the system, or the speakers, or the electronics will tell you everything you need to know.  Then you'll understand how big of a variance there is in recordings and soundtracks.  

Check out Paradigm's Premier or Prestige Series.  

Dear @daveyonthecoast : Your Zu speakers in reality can't gives you or handled the bass range you are looking for. In reality its works as a small monitor speaker and the manufacturer specs confirm it:

"  Bandwidth: 45 – 22 kHz  "  no one could ask for bass true bass with your speaker, it's a design limitation in its price market price.

I never heard that Zu model but I can think that over 80hz could be a good performer.

What your Zu speakers need is to add/integrates a pair of self powered subs system wired in true stereo fashion. You don't need anything else as could be to buy new speakers.

Look for subs that comes with high-pass filter because you will need it.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.