From Simon Ethan:

Re: Most horrible sound: vomiting, study finds (Jan. 24): There is what I consider a serious flaw in the research about what sounds people find most distasteful. When recordings are digitized and compressed, very high and very low frequencies are often truncated, which can markedly affect the character of a sound. Acoustic sounds change dramatically when recorded — regardless of the quality — and the results of this research may have been very different, had it been done live (nonviable as this would have been). Nails down a chalkboard owe their chilling timbre to the harmonic frequencies they produce, and those would have to be present to create that shudder. On another, more distrubing note, I watched to the video of Nick Berg’s decapitation in Iraq years ago. Another captive was being tortured off-screen, and the genuine screams that came from that person were far more unpleasant than any of the sounds offered in the study. I doubt a minority would agree.