Sub w/a CJ ET3 SE

Take a look at this SVS SB-1000. The owners manual will show you all the options for hooking up a sub. BTW,I think that the SB-1000 would be a good match with the 5T’s!
https://www.svsound.com/products/sb-1000

I have the same preamp on my second system and I use a splitter for the sub and it works great.

Yogiboy and ricpan thanks. My local dealer sells SVS and he may have that model on hand. 

I've got an CJ ET3, too
Velodyne F-1500, old one, but goody

I used a splitter adapter ( solid piece from audio quest & works well

bass is now seamless 

Jeff

I better add a few notes.......

If you have a Johnny One note sub
Try DIRAC room software
If you have a "one note" room node, my guess is it will be the same unless new sub has frequency adjustments 

The Dirac & A cheap USB mic really is amazing what it can do

Amarra has a trial you can try 
all you need is a $65 USB mic and you can hear it yourself 

I know the frustration of " one note" bass

jeff