In this article we introduce a method named "reference sound level calibration", and this article briefly presents and illuminates how to realize this method.

To verify the accuracy and reliability of the system, contrast tests on reference sound power source and small motor are performed respectively in a semianechoic chamber and a common room.

In addition to visual tuning via meter, the GA-30 can play reference pitches from its internal speaker (Sound Out) for tuning by ear.