The Science of 45s

On January 10th, 1949, The Receiving Corporation of America, (RCA), in heated competition with Columbia records, unveiled a brand new 7-inch record size that would eventually become the most popular format in recording history. Affectionately known as the “single” and characterized by a large central hole, it was an immediate hit.

History shows that through this innovative medium, billions of dollars would be made by record companies as they threw in their lot with rock and roll artists including Elvis Presley, Frank Sinatra, The Beatles, The Rolling Stones and countless others during the heyday of the '50s and '60s.

The RCA invention was simple and in addition to the physical difference, replaced the old brittle shellac composition with a novel unbreakable vinyl chloride material. The smaller disc also ran at a new playing speed of 45 RPM, replacing the old 78 which had been around since the turn of the century.

Young people liked the "45" because it was easier to grasp and place on the turntable using the central hole to slip your finger through. Continuing well into the 1980s with newcomers like Elton John and the Police, this design was such a money maker that its inception deserves some mention, so let's take a quick look at the history of records.

In 1877 the great American inventor Thomas Edison constructed the first acoustical recording device. He named it the phonograph. This instrument used a wax cylinder onto which a metal stylus imprinted information corresponding to vertical vibrations of incoming sound waves as they impinged on a diaphragm attached to a recording needle.

Although slow to recognize the financial potentials of such a discovery, he eventually made a lucrative industry of producing entertainment "records" from people of the day such as violinist Erna Rubinstein and bandleader John Philip Sousa. This awkward tube design dominated the fledgling music industry through the early years of the 20th century primarily because of the doggedness of Edison, who believed a rotating cylinder offered the best sound quality. This was not to last, however, and by the end of WW1 the flat disc record, an invention of rival Emile Berliner, began to gain in popularity.

Nevertheless, in either system, playing back the music correctly required the speed of the rotating cylinder or disc to match the spin it was recorded with at the factory. In those days, before the advent of household electrical power, all phonographs were hand-cranked springs that relied on mechanical governors to regulate the turning. Somewhere along the line 78 revolutions per minute was chosen as the most desirous for sound fidelity. This remained the specification for over 60 years.

When synchronous electrical motors appeared in the 1920s fixing their spin to the 60 Hz main frequency the velocity was refined to 78.26 RPM. This easily corresponded to the nearest 92 bar stroboscope markings often found on the rotating turntable. It is interesting to note that in countries on the 50 Hz frequency standard, the rotation was a little faster, causing records to squeak slightly higher in frequency.

It should be said that Edison was correct. A rotating cylinder was indeed the best for true fidelity recordings because the flat disc suffered from uneven frequency response. As the needle picked up the vibrations pressed into the plastic, the music initially starting out crisp and full of high notes, and became more muffled as the tonearm moved towards the center where the translational speed dropped in half.

But disc records did have one great advantage over wax cylinders in that they could be made larger in diameter. A 10-inch diameter disc could play for more than four minutes, while contemporary cylinders could only play for two or less. Plus, discs were obviously easier to manufacture over their wax competition. Most were pressed out of plastic material one-third shellac and two-thirds mineral filler with carbon black added as a colorant.

This format remained the standard throughout the Great Depression years and WWII. All of the music of that era, from Glen Miller's "In The Mood" to Spike Jones' "Der Fuhrer's Face," were sold on 78 RPM shellac discs, an honored speed that would shortly be challenged for both technical and competitive reasons.

In 1948, Columbia Records offered the 12-inch Long Play (LP) 33⅓ RPM microgroove record in a format called an "album." No longer would you have to get up and go to the record player to physically change a record after each song; there were up to six selections on each side. This brainchild of Peter Goldmark, chief scientist at Columbia, immediately incensed David Sarnoff, president of RCA, who by the way hated Goldmark. You may recall that RCA was a major manufacturer of 78 RPM records under Victor division, (remember the RCA trademark dog Nipper looking into the phonograph).

Sarnoff retaliated the next year by releasing the 45 RPM. You couldn't play them on your 78 gramophone because you didn't have that speed nor could you change your player to adapt the new record which didn't fit on your spindle. To actually play this 45 record RCA marketed a compact 45 only player that included a changing mechanism allowing multiple disks to be stacked and played one after the other. Since the maximum recording time of the 45 was only about eight minutes, RCA claimed that the new high-speed changer rendered interruptions so brief as to be inconsequential.