I was curious to know how those old, cumbersome, scratchy, vinyl records work. What process is used to make them and how do they get the music onto the record? How does the stylus of the record player read this media and transform it into music?
This was discussed recently…
http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=154193&highlight=records
This is an easy principle, really. First, Edison discovered how to capture a soundwave, and then he discovered the reverse process gives us Rock ‘n’ Roll! (In a nutshell!) Here’s the details:
Edison first discovered that a sharp object, like a needle, could cut a pattern onto a softer surface, like a vinyl or wax record. If the needle is attached to an object that can oscillate under the influence of a passing sound wave, much like a tree branch moving to a breeze, the pattern of the sound wave can then be preserved if the vibrating needle brushes against a soft surface of wax (he invented wax paper) or vinyl. But, who wants to just preserve a soundwave?
Well, Edison then wondered what if the process were reversed? Edidon discovered that if the preserved soundwave is then allowed to move past a stationary needle, such as on a turntable, the needle’s vibration will be dictated by the pattern engraved on the record rotating below it. Then, the vibratating needle will reproduce the exact sound as the wave pattern cut into the record medium (i.e.: wax, vinyl, etc.)
Finally, an amplifier was added to magnify the soundwave produced from the source. In the old Victrolas, the big horn with the needle attached at the far end WAS the amplifier.
One problem, though…deep sounds have a long wavelength which eat up a lot of space on the record medium, if reproduced at a 1:1 ratio. Some ingenuity came up with ways to scale down the soundwave to make it fit on the medium, and then the amp would scale the sound back up to the desired “size” of the soundwave.
Hmm… this simple explanation fails to explain how both bass and treble are recorded simultaneously (or reproduced simultaneously) without interfering with each other. Maybe another SDoper can explain this finer point of Edison’s technology.
- Jinx
Hmm, that wasn’t how I imagined a record working, I was thinking more along the lines of a CD’s microscopic “pits”, but somehow in a analog form. Thanks for the link Reeder, now I can sleep well tonight 
Dang, I knew someone would pre-post on me! And to add insult to injury, the dang board won’t let me post until 60 more secs pass me by! Dang! - Jinx
LOL @ Jinx. Thanks to you too Jinx, because when I was reading how the record actually worked, I was wondering how they got it on the vinyl/wax in the first place. Which at the same time, I suppose you were writing your reply. You saved me from making another post!
It’s called the superposition principle and it applies to all waves. Also, think about your eardrum, it is one single vibrating membrane yet has no trouble passing on all different frequencies simultaneously.