thanks i understand now ,i dont have the best software for modeling cabs for design i was going off what i have an web images for concept
I'm not sure you do understand. I have a strong feeling you are completely confusing isobarik and coupled cavity alignments.
Isibarik, just means two drivers are coupled in such a way that VAS is halved and therefore cabinet volume is halved. It never is that good because of the volume of the connecting tunnel which has to be added to the tuning volume.
Now an isobarik speaker can have an out facing driver or be a coupled cavity arrangement and so can a single speaker.
The only advantage of an isobarik speakers is cabinet volume reduction, it is all down hill after that.
I have a feeling that you think coupled cavity designs are isibarik, but they are usually not and do not have to be.
Coupled cavity designs were developed to control Q and produce a tight bass. However there is a close relationship between Q and bandwidth so that the lower the Q the lower the bandwidth.
Enthusiasm for couple cavity designs has waned unless you are Bose. They are high Q with higher bandwidth, which is why their bass is so ponky.
In the AVR world the LFE effects goes out to 120 Hz. It is impossible to design a good coupled cavity speaker with a bandwidth from 20 Hz to 120 Hz. In addition you only have port radiation, nothing from the cone or cones. So that is why enthusiasm has waned for this approach.
Isobariks are not popular as you double your driver cost, and loose output at the same time as gaining zero bass extension. I stress again that it is just a means of reducing cabinet volume at the expense of the above. It is nothing more than that.
If you want an isobarik design
here is one that I did.
This would the arrangement. The drivers are coupled by the air space between them, and they are wired in phase.
Here is a picture of an old KEF coupled cavity design from an era when it was popular. This design is coupled cavity, but it is NOT isobarik.
Those speakers would be wired out of phase.
I really think it was mainly the AV era and the need for wider bandwidth than coupled cavity can provide that killed it.
After all this I have no idea what you are trying to achieve and I'm not convinced you do either.