An accelerometer has a different natural frequency when it is in free space to that when it is mounted. The only frequency that is of interest to the user is, of course, the mounted natural frequency and is often the one quoted in the specifications.

The mounted natural frequency is dependent on the stiffness of the mounting structure to which it is attached and is therefore quoted as the natural frequency of the accelerometer as installed according to the manufacturer's instructions. Gluing, magnetically mounting or loose bolting the accelerometer down to a surface will significantly reduce the mounted natural frequency.