Vertical cut recording

Vertical cut recording was also used as a means of copyright protection by the early Muzak 16-inch background music discs.

In this process the stylus makes a vertical cut, its depth determined in accordance with the current in the recording coil.

The grooves of vertically cut records have a constant separation and varying depth, as opposed to grooves of laterally cut records, which have a varying distance of separation and constant depth.

It is necessary to set the parameters of the cutting depth accurately: too shallow a groove on silent sections and the playback device, also a needle, will slip out of place; too deep a groove risks cutting through the thin layer of recording medium and/or creating excessive wear when the recording is played back.

Due to mechanical noise generated by the recording system, the needle is never totally still; total silence would produce a flat even depth groove, so the hill and dale effect exists over all the audio recording section.