I downloaded shareware of the program and trying to get any parameters.

Further on I could try to refine the measurements.

I use 8 ohm series resistor (happend to find one in the drawer) and started a sweep.

Only Sd diameter entered as parameter.

So here it is what I got: http://postimg.org/image/svbawj28p/full/

The Fs about 52/3 Hz looks realistic. The speaker is a whizzer rated 55 - 5000 hz.

What is the second spike in the graph? Is it related to the whizzer cone?

Also, I don't know how to start the second measurement (added mass for simplicity)

The program does not provide any T/S parameters for now.

Just that graph with red and blue line.

I guess the blue line is the impedance response and the largest peak shows Fs.

Regards