It is not a matter of whether I disagree or not. Anyone with a basic knowledge of transmission lines, knows that the speed of reflection is so fast, that the signal quickly settles to the final value, and since we are looking at frequencies of <=20Khz and lengths of 7 meters, the error is literally smaller than 1000db.
Let’s talk about your "figure 3". As I stated previously, your scale is not defined (which another noted above), so it is hard to properly interpret comparative results, especially since in addition, you have a 2db roll-off at 20Hz, which we don’t know if it is causes by amplifier saturation, measurement roll-off, amplifier roll-off, etc.
Let’s talk about other errors. Your impedance shown in Figure 2, dummy load does not match the circuit. The 330uH inductor is 2*pi*f*l at 20KHz = 41.4 ohms. That is in series with the 7.3 resistor putting a lower limit on impedance of 48.7 ohms. The 1.4mh in the other leg is almost an open circuit at 20KHz. Yet you show 8 ohms impedance at 20KHz. Gee .... what could be wrong here? Could it be that your model is missing the Zobel that is typically on amplifiers for stability. Was that actually in your load or not? Hard to make claims when even the most basic aspects of your article are wrong.
Your appendix has a column Cable Fig. 2, but figure 2 is the dummy load, and the numbers in this column don’t actually relate either the traces Figure 3, or Figures 4-10 as there is no way to correlate them. The one marked XXXX appear to the same cable in 6, 7, and 8 meter lengths (point of that was), but in the Cable Fig. 2 column, it is marked 5, 4, and 6 which has no meaning to anything else. And then another marked XXXX that is 10 meters but is a different cable. I don’t know who you had peer review this, but you should fire them. I am up to at least 4 glaring errors without even getting to the conclusion.
So as I said again, Figure 3 is explain by inductance -- measured with a proper inductance meter close to the actual frequency, and as necessary, also taking into account skin resistance.
Of course, to properly correlate anything to Figure 3., you would need to fix the measurement errors, define what the scale actually is, define the readings on the spectrum analyzer (rms? voltage average, peak), and provide accurate inductance and capacitance values for specific cables as they relate to figure 3, something you have not done at all.
However, as I have stated in my previous posts, using educated guesses, variances of 4-5db in the cable drop method you have used would be what happens between the inductances listed for the several different types.