Discussion on Papers 15 and 16

DR SPLITTGERBER (Paper 15): In Paper 16, in relation to the threshold of perception, reference is made to recent work of McKay (reference 4 of paper). In Fig.l of the paper are represented the average perception level and several percen-tiles in comparison with level 2 of the ISO standard.

Defining the threshold of perception is a statistical problem, indeed. Without regarding other parameters one would expect a probability distribution for the threshold of perception depending on the number and the tested persons; the group of it will always be restricted.

In order to define the threshold of perception about 70 persons especially in sitting posture were tested not on a shaking table but in the normal environment of an office in a building by exciting the floor with steady-state sinusoidal vibration.1 The test room in our institute was installed with furniture as usual. The building is erected with prefabricated building parts and it was quite easy to excite the floor with a relatively small motor having an unbalanced weight of about 240 g. This motor was mounted in the room adjacent to the test room.