For all the high praises of vinyl LPs, you’ve never heard Nirvana quite like this. But it’s not the records fault. It has to do with how it was made by a Objet Connex500 state-of-the-art 3D printer. Amanda Ghassaei, assistant tech editor at Instructables, took it as her charge to be the first to print a vinyl record. The result is completely unique but full of flaws that would make an audiophile cringe.
The basic mechanism of a record is quite simple. A motorized platter spins a round disc at contant speed while an arm carrying a needle (also called a stylus) drags along a groove that spirals toward the center of the disc. The science behind picking up the signal from the disc is slightly more complex and is the result of Faraday’s law of induction. But if you want to make your own record, all you need is a disc with a groove filled with the right bends and bumps.
Ghassaei developed an algorithmic program that converts a source audio into a 3D printable file. This means a song comes in, and a 3D drawing of all the contours of the groove appears. This drawing acts as instructions for the 3D printer and a vinyl can be made.
Back when the record player and cutter were invented by Thomas Edison in 1887, the technology was not precise resulting in a large, deep groove that would quickly fill up the disc with only a couple minutes of sound. Since then, the technology has developed allowing for a miniature grove allowing a lot more data to be put on one side of a record and for that same data to have more detail creating a more realistic and accurate sound. Much like the first Edison record cutter, the best 3D printers of today can only be precise to a certain point (600 dpi with 16 micron steps for the Objet Connex500), which means that the audio quality is low-fidelity, the grooves are wide, and only a couple minutes of music can fit on a disc. The Connex500 is the first 3D printer to be able to cross the precision threshold required to print a record but it’s still short of industry grade by a factor of ten or so.
Ghassaei’s process for converting a digital file to an 3D printable file is possible because the grove of a record is more or less a microscopic image of the analog audio waveform. She takes the digital waveform, renders it to an 11 Khz sampling rate, and then generates a wireframe version of the signal. This wireframe version is then wrapped in a spiral around a 3D 12-inch disc.
“It’s really stripped down, it’s down to the bare essentials,” Ghassaei told Wired. “It’s really cool to kind of push the technology and see what you can get out of it.”