How Does a Record Do Stereo?
A record produces stereo sound by encoding two separate audio channels within a single groove.
Vinyl records achieve stereo sound through a clever method of engraving two distinct audio signals onto the walls of the record's groove. Unlike older monaural records which only varied the depth of the groove, stereo records utilize a V-shaped groove.
The Stereo Groove Explained
The groove on a stereo record is specifically cut so that each side, or "wall," of the V-shape carries information for one of the two stereo channels. This allows a stereo cartridge and stylus to pick up two independent vibrations simultaneously as the stylus tracks the groove.
According to the reference provided:
- The groove is actually V-shaped.
- Each side of the groove “wall” carries one of the stereo signals.
- The right channel is carried by the side closest to the outside of the record.
- The left is carried by the inside wall.
Here's a simple breakdown:
| Groove Wall Side | Stereo Channel It Carries |
|---|---|
| Closest to outside of record | Right Channel |
| Closest to inside of record | Left Channel |
How the Stylus Reads Stereo
A stereo cartridge typically uses a stylus with two sensors (or a single sensor designed to detect movement in two directions). As the stylus moves through the V-shaped groove:
- One sensor (or part of the sensor) reads the vibrations from the outer wall (carrying the right channel).
- The other sensor (or part) reads the vibrations from the inner wall (carrying the left channel).
These separate vibrations are converted into electrical signals by the cartridge. The signals are then sent to the amplifier, where they are processed and sent to the left and right speakers, creating the stereo effect you hear. This allows for spatial separation of sounds, giving depth and realism to the audio playback.
Understanding how the groove walls are cut and read is fundamental to appreciating the ingenious technology behind vinyl stereo sound.
