Profound VIBRA Series Manual page 12

Once the bracket is in place attach the geophone to the bracket, as
shown:
geophone
-
- glue bracket
- ring
bolt
-
Use the spanner /wrench to secure the geophone with the bolt. The
ball joint of the geophone facilitates precise orientation of the
geophone.
Define the measuring directions. The most commonly used method
is: the x-axis parallel to the wall, the y-axis square to the wall. Use
the vial on the geophone to check that it is level.
If the activities will find place at different locations, it is practical to
mount additional brackets to the wall before the measurements start.
Manual Profound VIBRA-series, version 2.00
12