taxis

All I want for Christmas is a Buchmann-Meyer pattern

Doing some reading for my current project (a history of the CD Audio format), I stumbled across a physical phenomenon that does not often crop up in discussions of the history of gramophone recording: the Buchmann-Meyer effect. This optical effect was once used to measure the quality of gramophone records, both qualitatively and quantiatively, by shining a band of light on a disc and capturing the characteristic “Christmas tree”–like pattern that is reflected back to the viewer.