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Below we see the effect of increasing the capacitor to 5 uF in the lowest (blue) trace. It seems we have
gone too far with the increase to 5 uF. The impedance in the 2 to 3 kHz range has been reduced to the
DC resistance value and is now rising above the previous measurement with the 3 uF capacitor. This
rise may be due to an interaction with the voice coil inductance. It looks like the 3 uF capacitor will be
the best overall choice to tame the driver's high frequency impedance.
The point of the exercise was to demonstrate how an inductance compensating network, or Zobel
network could be designed experimentally by "trial and error". Even if you choose to calculate the
values for the Zobel network you still might want to verify the resulting impedance response of the
driver with the Zobel connected. In general you could take the same approach to verify other networks
such as the resonance compensation network (R-L-C) sometimes used to neutralize the impedance
peak of a tweeter. As an impedance measurement system the additional applications for WT3 are
limited only by the user's imagination.