Here's the
review at cooling-masters (
auto-translated to English by Google)
IMHO, the enclosing box is a reasonable attempt to exclude external noises - as is simply squeezing the output hose gradually in order to record the sound variation with change in resistance ( for example, Iwakis at no-resistance are, to my ears at least, somewhat loud - but get quieter with more resistance).
I'd hope that whoever did these recordings still has the "box" and is at least thinking about updating with the c-systems mag - in fact they may have: I was semi-fluent in French - but over thirty years ago, so reading cooling-masters stuff goes pretty slowly for me and there may have been additional recordings made that I just missed / didn't get to.
I'm now thinking I should build one of these boxes for myself: I've started a
separate thread about building a sound enclosure so as to avoid having two divergent discussions in this one.