PIRA Classification: 3B55.47
Description: Two speakers are connected to the same frequency driver; however, a phase reversing switch is placed between one speaker and the driver. When the speakers are placed together and are in phase, a loud tone is heard. When the phase of one speaker is reversed, the tone almost disappears. When one speaker is then moved away, the tone returns.
Special Instructions: The generator should be set to 900 Hz.
Condition: Ok
Setup time: 2 minutes
Safety Issues: None