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

You would have a hard time getting the needle to track. The groves in the vinyl as made by peaks in the father. The needle will just fall off these peaks. If the groves are too close together then the needle might track between two of the peaks. You will essentially be playing the left side of one grove on the right channel and the right channel on the next grove on the left channel. But assuming you have a special inverted “needle” that could track the peak like the grove of a vinyl record then it would sound just the same. The phase of the sound is inverted but that is not something that the human ear can pick up. This would be like swapping around the two wires on your speaker.