MIT researchers have developed a new type of speaker for sound reproduction. Unlike the “classic” design, which requires multiple components and a large enclosure to produce sound, the new speakers are as thin as a sheet of paper and consume very little electricity. For a sound equivalent in intensity to that produced by a “classic” speaker, 10 times less electricity is needed using the new technology.
MIT’s new slim speakers are built using lasers
This new type of very thin speakers can generate clear and loud sound, whether they are left loose, or attached or even glued to a rigid surface. Other attempts to develop very thin speakers in the past did not allow it to work when attached to other surfaces, as the vibrations needed to play the sound could not be achieved.
However, the solution to this problem lies in a new manufacturing process. Instead of moving the entire “membrane” of the thin speaker, small laser perforations were made all over its surface. Then, under this membrane, a piezoelectric material called PVDF was attached. Exposure of the two materials to vacuum and a temperature of 80 degrees Celsius allows the material to penetrate through small holes, making small domes. They allow movement through each hole when electric current is applied to the entire system. This causes vibration to occur on the surface of the speakers, and there is no need for the entire speaker to move. PVDF domes are 1/6 the thickness of a hair, say researchers, and move by half a micron when vibrating.
Energy efficiency is much higher
100 mW is enough to power a square meter of such “speakers” to produce a sound equivalent to a 1W speaker. thus, the energy efficiency is 10 times higher in the case of new speakers.
These speakers could pave the way for more efficient and compact speakers, but they could also start new use cases for them. For example, you could “wallpaper” the walls of a room with such material and use microphones to create a completely silent room using ANC (active noise cancelling) technology, which introduces frequencies opposite to those that make noise to cover them completely. Or you could put such speakers on the bodies of electric cars to produce sounds that pedestrians could hear. Another use case could be in the field of security, being able to track the movements of people in a room by analyzing sound frequencies. Of course, there is also the possibility of turning these speakers into real displays. Domes could be covered with reflective elements to create images, like DLP technology on projectors.
Technology is still in its infancy, so it will probably take a long time to see real products based on it.