Acoustic calibrators are very simple instruments that allow you to verify the different noise measuring equipment at one or several sound pressure levels at one or different frequencies. In this way we have a team in the field which will indicate before and after each measurement the state of the equipment and allows us to know if the equipment is suitable for measuring tasks. These equipment’s are indispensable to ensure that a measurement is valid and although they are not a tool to calibrate a noise instrument if they are the way to verify its correct functioning.