This is a modified version of a setup used for R&D by a major loudspeaker manufacturer.
It measures the impulse/frequency response including harmonic distortion. Displays three plots. Upper plot: Frequency response (magnitude),Left plot: Frequency response and second and third order harmonic distortion.Right plot: Total harmonic distortion plotted in % on a logarithmic scale.
If you are not an experienced WinMLS-user, then