Quote:
Originally Posted by crich70
Interesting. I know there are 78's (very thick), 45's (the one song on a side) and 33 1/3 is the only other speed I know for LP's. I have no idea how fast CD's spin while playing back music.
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The reason for the 78 speed was that it was necessary for adequate sound quality for early records (which were made of fragile shellac). Due to advances in technology and materials, records were able to achieve better sound quality at slower speeds. The 45s and LPs were competitors at one time but eventually they were able to co-exist since they go after different markets. Added to this are the 12" 45RPM records which were popular for dance music due to their longer playing time.
Unlike records, CDs play from inside out (part of the reason is that they weren't sure how large a CD would finally be when the format was being established) and spin at different speeds depending on where the laser is reading. If I remember correctly, they spin at 400 RPM when they start playing and slow down to 200 RPM as the laser moves outward (it's likely related to the CLV format for laserdiscs, which doubled the playing time for each side of an laserdisc).
New Trivia Item: David Kaye is the only individual in the Transformers franchise to voice both Optimus Prime and Megatron.