The screen captures look like Multisim, a spice simulation program. The big hint is the "oscilloscope" icon wired into the output.
Hi!
I'm using REW for Impedance Measurement.
512.000 are total samples. With the sound card set to 48.000Hz, you get 512/48=10.67s.
Here's the definition of this setting from the manual:
"The length of the sweep, specifying the number of samples in the sequence. The default is 256k. Dividing the number of samples by the soundcard's sample rate gives the sweep duration in seconds, shown to the right. The overall duration includes silent periods before and after the sweep.
The R+L network on the output of an amplifier starts to protect the amplifier negative feedback at frequencies above about 1 MEGA HERTZ. It isolates the amplifier feedback from the loading effects of the speaker cable. It might also be important if you were driving a highly capacitive speakers, like electrostatic. Its function is to prevent loading high frequencies, well above audio frequencies, which might make the amplifier oscillate. Inductors at the other end of the speaker cable are not useful for this purpose.