Hornresp

[Bluewoldemort]

Ok so I made BP6, TH and PH3 as close as I could without decimals.
BP6:

PH3:

TH with a rear chamber as the stub and throat adapter and port as the rear chamber:

So TH and PH3 look pretty similar and both have a tuning around 26/58, but BP6 still has a lower tune of about 24/51Hz, and all of them are 316l +-0.5l.
So it must be the stub between the cone and front chamber that raises the tuning because it is simulated in both TH and PH3, but not BP6.

 

[Bluewoldemort]

Also I found a graphical bug in at least the PH and TH models. Not sure if this is known
When you change e.g. the L12 value it copies the graphical value of S2 to S2S and S4 to S4S, as seen on the S2S slider:

 

[BP1Fanatic]

The BP6S function doesn't open up the bottom fields to add a stub.

 

[BP1Fanatic]

That sounds right since you started with the Stepped function (red segments) on the home screen of the TH and Paraflex.