Here we are ready to measure Thiele/Small parameters of a Focal 7K4412 woofer, through the impedance response. The first thing to do is to break-in the driver, cause you can get up to 25% parameters differences between a new and broken-in driver. I use SW to generate a sweep signal from 10 to 100 Hz but you can test different ways to break-in. Of course you will need an amplifier if you use SW generator!

While the Focal is breaking-in, let's think on how to hold it during the measurement: we have to prevent unwanted vibrations! Here's two possible solutions: 

It's important to test the driver vertically, as this will be it's final position once installed in the box; moreover keep it away from reflecting surfaces that could alter the measurement. This is what I used:

Once the break-in ended and the driver holder is ready we can start the impedance measurement. As a general rule it's advisable to let the driver play for 30 minutes then wait a couple of minutes (to let the coil cool down) and finally start the measurement. The IMPEDANCE CABLE with the reference resistor (11.15 Ω) will be used and the driver will be connected to the DUT CABLE (the light blue one) paying attention to respect the polarity. We are ready for the measurement .