In a stereo recording, the two channels are arranged to drive the record cutter head at an angle of 45° to the vertical, effectively encoding each channel in the left and right V-shaped walls of the record groove. This system worked well, since it provided full compatibility with a monaural pick-up, so stereo records could be played on older mono equipment.
See drawings of pick-ups above on that page. The vertical movement of a monaural pick-up stylus will be the sum of the two stereo movements. Each channel contributing with an sqrt(2)/2 amplitude of its 45° amplitude.
From: http://en.wikipedia.org/wiki/Magnetic_cartridge#Stereo_repro...
See drawings of pick-ups above on that page. The vertical movement of a monaural pick-up stylus will be the sum of the two stereo movements. Each channel contributing with an sqrt(2)/2 amplitude of its 45° amplitude.