laser Tool

[jerryo]

I have just read about a new imaging tool that has been created by the National Physics Laboratory in Teddington (UK) for observing the behaviour of lodspeaker drive units. Using a Laser Vibrometer a light is shone across the speaker and then reflected back.

"Light waves change their phase when reflected, and interacting with sound waves can affect this change because light travels faster in lower-pressure air. The device picks up the phase differences"

It would be very interesting to see this in action.