11/3/2023 0 Comments 33 1 3 rpm![]() ![]() Then in 1947 CBS came out with it's own version of the consumer 33 1/3RPM Long Playing disc and RCA had a corporate tantrum because they couldn't believe CBS's upstart tiny little R&D department (relative to RCA's) were able to overcome the technical obstacles mighty RCA couldn't. Bad sound, bad press, and no real direction on it's purpose killed it and it was soon forgotten.even by most of RCA themselves. RCA first introduced long play 33 1/3 RPM discs for the consumer back in 1931 and it was a major flop. (Radio co-opted the speed for it's own 16 inch discs, as did RCA for it's disastrous early 1930's era long play consumer 33 1/3 RPM record.)Ĭlick to expand.I heard this story too, but actually, it's kind of the reverse. And it just so happened that the speed stuck around long after Vitaphone faded away as a sound for film process. sound quality all combined made 33.33RPM the speed for that purpose. In Vitaphone, the projector motor also drove the turntable, so each had to be locked to a clearly defined speed and each 16 inch disk had to have a playing time as long as one reel of film (10 to 12 mins) and still sound good. And mathematically, 78.26RPM was chosen, again as I have read, because it had to do with motor speed vs pulleys etc.ģ3 1/3RPM is similar: it has to do with it's original use as the sound disk in the Vitaphone film sound system. (I believe in the mist of my memories I remember reading most electric motors back then ran at 1500 to 1800 RPM as a rule.) So you had to use things like pulleys, idlers, or linkages like you see in old watches and record changers to achieve target speed. And again, it had to do with raw motor speed and what the various ways speed could be "stepped down." If you notice, many turntables today say things like "Powered by a 24 volt 300RPM motor." Same thing then. That's why all those old acoustic phonographs have fairly wide speed controls - motors weren't all that accurate back then.)ħ8.26 came after electric motors became the norm. (Those early acoustic discs can be anywhere from 70 to 90 RPM. After all that, around 78RPM was that median. So supposedly it was a balance between availability at the time of a smooth enough high-speed spring wound motor that had low cogging and acceptable speed stability combined the kind of common step down pulleys available to come up with a median speed that would give a reasonable playing time per disc vs. The earliest Berliner gramophones actually were closer to 80RPM on average than 78.26.īerliner had some set goals: he wanted a flat disc that sounded at least on par with Edison's cylinder, and with the disc size he was proposing (5 to 7 inches) it had to play at least as long as a typical Edison cylinder of the period. It bears remembering, the 78.26 speed came about over a period of time and wasn't "locked in" until well into the shellac disc's lifetime. (Forum speak for "I can't name or remember the actual sources, so take this at face value and don't quote me but this is the gist.") None of it was happenstance, and almost all of it had a solid engineering and mathematical basis.Īs I recall it. And all were connected to the various technologies of the time. ![]() Over the years I've heard more scientific explanations for the choice of speeds records play at. Lots of bad, oversimplified and just plain wrong info there. The time of wax cylinders also had to reach a dead-end because as technology started to build around Phonograph, improvements and ideas poured into other scientists’ brains and that led to the birth of devices with different parts and later on different technologies.Click to expand.That's a pretty poorly researched and written webpage. Also, his marketing strategy for selling his machine was not effective as the target audience for the Phonograph were two – people who were wealthy enough to indulge in such a novelty and the scientists who were interested in the technology behind it. The tinfoil used was delicate which meant that it can only be used twice or thrice and couldn’t be stored for a long enough period. But things weren’t going as smooth as everybody thought they would. Here the sound vibrates a needle that etches grooves onto a cylinder made of tinfoil or wax. While at that time other inventors had their magic machines only producing sound, Edison’s Phonograph reproduced sound! The phonograph works in three different stages. Okay, so why do records spin at 33 ½ rpm? The answer to this simple question dates back to when Thomas Edison recorded sound in his Phonograph and later on, wax cylinder in 1877. ![]()
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