Mixing of 'in phase' and 'out of phase'  signals is known to add to perception of image depth.It has something to do with how the brain interprets phase & arrival times.

Before I give a wrong idea, the bass is certainly not the strong suit of this design. But. the bass isn't as lacking as my previous attempts with the stock pmb & HP50 drivers. Certainly listenable.
I can extract more bass out of this if I seal some part of the vent (I did that using blutak on my other PMB-80) but the soundstage would certainly suffer.

I wonder why no manufacturer is trying this in the neo-orthos. Most of them have huge drivers & plenty of bass to spare.
With a little effort, they could probably achieve a lot more controlled mixing of front & back wave.But then, may be I expect too much out of headphone manufacturers.
 

The SS effect of leaky pads is minor at best, IME.

BTW, that reminds me that I can get better bass by using O2 pads. Gotta try that. 

BTW, that reminds me that I can get better bass by using O2 pads. Gotta try that. 

Now we are talking.
guess I'll have to buy another pair of O2 pads.

YES!!!  This makes me comfortable planning to put my Super 7 on the incoming PS Audio NWD.

BA knob on the Super 7.  Took no more than 3 hours max.