MIT develops a speaker thinner than sheet music

If you’re into cars, you may have heard of vinyl wrapping, which can change the appearance of a car. Engineers from MIT have taken a similarly thin material and created a skinny film that can turn pretty much any surface into a speaker. According to its inventors, it can create high-quality audio with minimal power consumption.

To achieve these properties, the researchers created a fabrication technique. They claim it can be scaled up to produce ultra-thin loudspeakers large enough to cover the inside of an automobile or to wallpaper a room, whispering a promise of immersive sound without an obvious source. The audio nerd in me is definitely feeling a cochlear hard-on coming on. (Yes, that’s a dick joke, but if your cochlear fuzzies were to stiffen you’d be deaf, so anatomically it makes absolutely no sense. The lengths I’m willing to go to for an infantile joke are legendary.)

The loudspeaker could be used in active noise cancellation, for example — combine the speaker tech with some electronics and microphones, and it could cancel out sound. The inventors also envision immersive sound experiences, and other low-energy use cases such as smart devices, etc.

This thin-film loudspeaker produces sound with minimal distortion while using a fraction of the energy required by a traditional loudspeaker. The hand-sized loudspeaker the team demonstrated, which weighs about as much as a dime, can generate high-quality sound no matter what surface the film is bonded to.

“It feels remarkable to take what looks like a slender sheet of paper, attach two clips to it, plug it into the headphone port of your computer and start hearing sounds emanating from it. It can be used anywhere. One just needs a smidgeon of electrical power to run it,” says Vladimir Bulović, the Fariborz Maseeh Chair in Emerging Technology, leader of the Organic and Nanostructured Electronics Laboratory (ONE Lab), director of MIT.nano and senior author of the paper.

Bulović wrote the paper with lead author Jinchi Han, a ONE Lab postdoc, and co-senior author Jeffrey Lang, the Vitesse professor of Electrical Engineering. The research is published today in IEEE Transactions of Industrial Electronics.

Most thin-film loudspeakers are designed to be freestanding because the film must bend freely to produce sound. Mounting these loudspeakers onto a surface would impede the vibration and hamper their ability to generate sound. To overcome this problem, the MIT team rethought the design of a thin-film loudspeaker. Rather than having the entire material vibrate, their design relies on tiny domes on a thin layer of piezoelectric material that each vibrate individually. These domes, each only a few hair widths across, are surrounded by spacer layers on the top and bottom of the film that protect them from the mounting surface while still enabling them to vibrate freely. The same spacer layers protect the domes from abrasion and impact during day-to-day handling, enhancing the loudspeaker’s durability.

“We have the ability to precisely generate mechanical motion of air by activating a physical surface that is scalable. The options of how to use this technology are limitless,” Bulović says.

There’s no word on if or when the tech will see the light of day in consumer or commercial applications, but I’d wallpaper my living room in speakers in a heartbeat just to get rid of the wires and the speakers bolted to the wall.