Impedance measurement deviates from simulation

[Stollery]

Hi, wondering if anyone can help me understand why the impedance measurement of my vented enclosure differs from the simulation so much. Particularly the size of the lower hump associated with the port.

 

[bentoronto]

C'mon, the fit is astonishingly good in the real-world.

Any sim skeptic (or anybody with experience measuring acoustic gear) would be amazed.

But the red (measurement) curve looks oddly smooth and regular to my eyes.

 

[rayma]

why the impedance measurement of my vented enclosure differs from the simulation so much.
Particularly the size of the lower hump associated with the port.

The tuning is not what was expected, some of the model parameters are off.

 

[Stollery]

Thanks for the comments, playing with the parameters it looks like the Q of the port changs the size of the hump - the Fb is ok. How can I influence Qp in real life?

 

[David McBean]

some of the model parameters are off.

The value of Le would appear to be too low, for one 🙂.