When pressing vinyl records, a stamp called a “father” is used which is an inverted copy of the original, with ridges instead of grooves. What would it sound like if you played it on a normal turntable?

Question

When pressing vinyl records, a stamp called a “father” is used which is an inverted copy of the original, with ridges instead of grooves. What would it sound like if you played it on a normal turntable?

In: Physics

Answer 1

The other answers explaining how your grooves would be ridges is part of the story. If we are talking about a stereo record opposed to mono, then two channels of sound are stored in the groove. One is created by left-right vibration on the center line of the groove. If the recording were only on this channel the needle would vibrate left and right but not at all up and down. On the other channel the vibration is created by changing the width of the groove. As the groove width varies the needle vibrates up and down as it sits deeper into a wider groove.

So now we imagine that the needle runs a half groove out of sync. There would be no rhyme or reason to the groove width or centerline. Both the width and centerline of both grooves you are touching would impact both vertical and horizontal vibration.

Long story short, you would simply get noise not a distorted or off time version of the recording.