With the measured T/S parameters we can verify them using an Excel spreadsheet that you can download. Moreover other missing parameters will be calculated. Another option is to use a program written by Bruno Dalle Carbonare, that calculates T/S parameters starting from the free air impedance and the added mass or the closed box one.

 Let's start with the Excel file:

 The numbers in red are the one we have to input, the blue one are the calculated. Just write the parameters SW calculated while for the Zmax, that is the impedance max value, we can get it from the   chart, zooming in the peak and passing the mouse cursor on it we can read its value in the STATUS BAR, as we did during the Vas measurement:

 Repeat it for the chart, where we will read both the Zmax and the Fsm (Fs with added mass):

 In the calculated parameter section of the spreadsheet we only need to input 2 values: F1 e F2; to do this we read the value of ZF1,ZF2 (that is the impedance at F1 and F2), and we must find in the  chart these two frequencies, one lower and the other higher then the Fs, at which the impedance is equal to the value of ZF1,ZF2 (24, 74 Ohm). You can use the mouse cursor/status bar procedure, or we can convert the impedance chart in numbers: with the chart opened click on RESOURCE/ EXPORT, and give a name to the file saving it; now open it with WordPad or Notepad:

 The first column are the FREQUENCIES, the second the IMPEDANCES and the third the PHASES (at 33.325 Hz the impedance is 24.27 Ohm with a phase of 60.90 degree); as we can see the generated numbers are a lot and it depends on the setting of the Sample Size in the SW setup (menu OPTION/ PREFERENCE/ MEASUREMENT). Highlighted there are the more close values of the ZF1; of course it will be impossible to find the exact value (24,74 Ω) so we interpolate the two closest values; so the first value, F1, is equal to 33.50 Hz. Repeat the search for ZF2 that will be found at a frequency higher than Fs (44.94):

 Here too we have to interpolate the two closest values so that we come to an F2 = 59.75 Hz. Write the two values, F1 and F2, in the Excel spreadsheet and we will be able to see the differences between the measured and calculated parameters: definitely a very good result! Notice that is calculated the driver Le at 1k and 10k Hz, using only the real part of the impedance, by just writing the impedance value (Zl) seen on the chart at those frequencies.

A last area in the spreadsheet allows us to calculate the average between the two driver: just write the parameters (Focal A and Focal B) as calculated by SW and use the calculated average for the speaker project.

Bruno's program is easy to use, and it is able to import any impedance response that has 3 fields like SW one. Once launched, if the language is not English, just open the file menu and select the English file. Then put the few parameters needed, and you will see:

 Differently than the Excel file, where the parameters are taken from those calculated by SW, this program calculates on its own starting from the zero phase frequency for the Fs and the maximum impedance point; the results obtained from the program may slightly differ from the SW's ones because a different mathematical model is used. However low "Difference %" confirms that the measurement is valid, presupposing that the measured curve is reliable.

 In case of mistakes, the program shows some warnings:

 Here the program tells us, putting in red and with a message box (not visible in the image above), that the impedance files have more than one zero phase point (5 the free air and 7 the added mass one), therefore it should be better to lower the Speaker Workshop resolution and to repeat the measurement. Also in red is the difference between the free air and added mass Fs, and the message box warns to increase the weight of the added mass because the 25% shift hasn't been reached. A user reported a Run-Time error when importing a curve: it was due to a dirty measurement below 10 Hz, and can be easily predicted loooking at the chart in  SW; in this case, open the exported file with the notepad and delete all data below 10 Hz to solve the problem, that is caused by the measurement, not the program.

 With the program it's possible to use the closed box method, for the calculation of the Vas. You can take it in the download area.

 So now you have all the datas to start your project, so just go on! We will see again when the box is ready for the speaker impedance measures  using Speaker Workshop.