ML TQWT: is it whistling ?

[teodorom]

I’m still trying to understand and, as someone else says, <the more I know, the less I understand>.
My last question was about the position of the port in a ML TQWT. I asked it because in the ML TQWT model that parameter was not there. Then someone else pointed out the one could use the Ported Box model (right ! the underlying math is always the same): the simulations I’ve done since then confirm that assumption.
Then I tried to understand if the standard calculations about the speed of the air at the port could be used for the ML TQWT.
I tried with the models exposed by http://www.mhsoft.nl/PortLength.asp and http://www.linearteam.dk/default.aspx?pageid=ventcalculator .
If, for the Fostex FE-164 (the one used in yours papers and in ML TQWT.mcd) I put Box Volume: 80.01 Liters, Length of the Vent: 2.51 cm, Vent Diameter: 7.2 cm. I get consistently for the Fb = tuning frequency: 44.3Hz.
To be sure that the reasoning works I modified the Vent Diameter, and consistently (using the results provided by the above models) the Port Length.
The SPL diagrams where coincident (up to 200 Hz and up a Vent Diameter of 16 cm, and Port Length of 26.709 cm) !
The problem is that, given the first model, the Port starts whistling at 1.6 W.
So, why a ML TQWT shouldn’t do the same thing ?
Thanks