[LAU] speaker frequency response measurement and display

Hi there! I want to display the frequency response (amplitude, impedance and maybe phase) of my self-build speakers on my homepage. I like the clean look of gnuplot and I wonder if anyone knows about a manual for linux- users to make "clean" speaker measurements (with room influences eliminated as far as possible) to get an output in a style like this: https://3.bp.blogspot.com/-Zsqjk1N1Sws/V2xYWnunOrI/AAAAAAAAAWE/aYPZLa2x ItYkpFLA3f1zO25IN_AjPY_PACLcB/s1600/eq_smooth.png (just 1 amplitude, of course, and with a dB range of 80 to 120, f.e.) I have some experience in speaker measurement, but unfortunately I'm not that smart to write my own octave-scripts. I'm just a linux-audio- USER, you know. Greets! Mitsch