Locating method for plumb line family through middle point on axis of spirit level

摘要

The locating method includes the use of two microphones (4, 5) arranged at the spirit level (3) with the same preferential direction, at both sides at an equal distance from the measurement plane (10). The microphones are connected with an electronic evaluation circuit (8). The time displacement of their output signals to each other, with the impingement of a pref. spherically shaped sound pressure front, is used for determining the relative position of a pref. point shaped sound pressure source (11) to the measurement plane (10).