Although the same general principles are used in recording monaural and stereophonic recordings, the way the discs are cut differs.
Monaural, or mono (one-track), recordings were the earliest recordings. These are produced by cutting a V-shaped groove with a laterally-oscillating stylus. This forms grooves of a wavy, "wiggle" shape. Once the record is pressed, it is played back by means of a mono (or stereo) turntable. The pickup head contains a stylus, or needle, which is conical in shape with a spherical tip. This stylus traces the groove on the recording, and this motion is translated into the appropriate electrical impulses by means of an electromagnet. These impulses are strengthened by an amplifier, and then are reconverted to sound by means of a speaker.
Stereophonic, or stereo (two-track), recordings are made in much the same way as monaural recordings. The only difference between the two is that stereo recording uses a laterally- and vertically-oscillating stylus. The stereo cutter head has two complete electromagnetic mechanisms arranged in such a way that they apply each channel of sound to a common stylus. Since the groove is V-shaped, it is possible to have two grooves in one, in effect. Each side of the "V" represents a different channel and has a distinct wave pattern to be picked up by the stylus. A stereo stylus picks up the sound in the same way. Naturally, stereo sound is much more difficult to produce than mono sound, and the equipment must be considerably more sensitive.
It is important to note that stereophonic records should
never
be played on a monaural record player. Damage can result, as a monaural
stylus is not designed to pick up vertically-cut grooves. A mono
record can, of course, be played on a stereo record player.