Hello SpaceMonkey,
Thanks a lot for your info on xsim and the YouTube link.
Yes, xsim is a interesting LCR network simulation (educational?) tool. I have xsim installed in my PC workstation, and tried it several times.
With xsim, to configure and simulate LCR network is rather easy and straightforward. I always feel much frustration, however, to fully characterize the virtual SP units (drivers) with xsim even I would have detailed spec sheet of the driver. Also it would be almost impossible to simulate the characteristics of specific enclosure of the speaker(s), and also impossible to simulate the room acoustics, of course. I do not deny the fundamental educational value of xsim on PC.
Even in case I would have really nice, almost flat Fq response over 20Hz - 20kHz actually measured by ECM8000 microphone, I could never simulate it with xsim in PC.
I agree with you that xsim can be used to see only the "tendency" in Fq response change, e.g. tendency for connect or disconnect one resister in parallel with a SP driver. It would be almost impossible, to determine the best R value using xsim. I believe we need to trust our ears and brain in fine tuning procedures, as you would fully agree.