I'm up to my eyeballs writing a paper, but briefly, as Dave asked me to take a look at this, I suspect we're looking at variations in the modelling basis. All the basic modellers should be running the same baseline maths, but they tend to show some shifts when you incorporate other assumptions (e.g. damping, box leakage, port frictional losses etc.) even if you adjust the coefficients to nominally the same.
Attached; this is with the published data & 0.5ohm series R added for wire loop, connection resistance. All boxes of the same Vb & Fb.
Top left & centre = a modified variation of MJK (which from long experience I know to be reliable), with the dimensions stated above adjusted for internal, and the equivalent of about Qa = 40 lagging.
Bottom = Unibox, which is usually consistent with MathCAD and I usually find consistently reliable to measured.
Top right is BassBox6pro, which has some qualities, but I tend to find sometimes shows some variation in alignment terms with the same specified nominal dimensions, tuning, damping, leakage etc. YMMV. In this case, it appears closest to the WinISD alignment indicated in the post above, whereas my modified version of MJK and Unibox are closer to Dave's, although adjusting for the different graph scales, in fairness overall they aren't all that far apart.
Attached; this is with the published data & 0.5ohm series R added for wire loop, connection resistance. All boxes of the same Vb & Fb.
Top left & centre = a modified variation of MJK (which from long experience I know to be reliable), with the dimensions stated above adjusted for internal, and the equivalent of about Qa = 40 lagging.
Bottom = Unibox, which is usually consistent with MathCAD and I usually find consistently reliable to measured.
Top right is BassBox6pro, which has some qualities, but I tend to find sometimes shows some variation in alignment terms with the same specified nominal dimensions, tuning, damping, leakage etc. YMMV. In this case, it appears closest to the WinISD alignment indicated in the post
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