Here is some amusing copy from the box of a Grundig GRM1, a.k.a. Lustraphone VR53. Above the nice diagram of the the figure 8 pattern, it proudly states "There is virtually no sensitivity at right angles to the microphone front, and this we call the "Dead Zone". Now we know what to call it!
The Xaudia blog has also been a bit of a dead zone in recent weeks, due to lots of repair work coming in. Things are getting back under control, so more microphone related posts and info will be coming soon!