Help me with delay

Thats wrong actually.  You will need to delay the tops to time align with the X1.  BP6 type boxes tend to have quite a high group delay.

The best way to set up your delay is to use a tone generator or sine wave cd.  Start by phase reversing one of the boxes.  Then play a sine wave thru the system at the frequency you want to crossover at e.g. an 80hz sine wave if you crossover at 80hz.  Then start to delay the top box until you hear the tone go quieter.  There will be a point where the sound will be quietest.  Now change back the phase of the box you reversed. 

This is the correct delay setting for that crossover frequency.  If you wish to change the crossover frequency you'll need to do this again as the group delay can change quite drastically over very small frequency changes.

My BP6 box has a very large spike in the group delay at 80hz and goes up to 15ms.  Alternatively you could model the box in WinISD and look at the group delay graph but this is likely to be less accurate

BUT do the WinISD thing in addition to see if the settings are reasonable. Working with sines will give pretty accurate 0° aligning, but who says that it is the same cycle? So checking for reasonability (can I say that?) is pretty useful.

After aligning the boxes you can't change anything on your setup! No change of ANY filter frequency (highpass aka subsonic and lowpass on the sub, highpass on the top, even EQs in the outputs MUSTN'T change!), because they will change the groupdelay for that output on the crossover.

Another good way is to use the Behringer UltraDrive as LMS. With an ECM8000 attached, it can measure the needed delays by itself. IMO it is the best LMS below 800 Euros anyways (Yes, better than the DriveRack PA!).

JD01 wrote: Working with sines will give pretty accurate 0° aligning, but who says that it is the same cycle?

With bass you should be ok - at 80hz a cycle is over 4m long.  You've got to be a fair way off the mark before you get a whole cycle out.  As you move up the frequency bands you've got to be a bit more accurate with your initial guess...

You'll need to delay the tops.  It doesn't really matter which cab you reverse the polarity on but it might be easier to do the sub.

It should have made more noise at 80hz than 44hz as it should be playing more frequencies that you can hear.  Are you using a hi-pass filter on the bottom end?  What filter and slope are you using on the top end of the X1?  Are you cutting the tops off at the crossover frequency or letting them play full range as this could cause cancellation