I personally didn't take the time to read the text because it didn't look like a scientifical document. No explicite methodology part and so on. The only thing that can't be subject to personal opinion are graphs. About the figure 17, it's not the K371, it's another headphone on the graph.

I had no intentions to support a position. Do you know what cognitive biases are ? I hope yes because I know what they are. I'm not the kind of people that want to manipulate others.