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Nanoparticles Enable Novel Loudspeaker Design

Loudspeakers using nanoparticles in place of permanent magnets may deliver better sound quality

2 min read
Nanoparticles Enable Novel Loudspeaker Design

While technological developments in personal computing always seem to be eagerly received, it seems that developments in our personal entertainment—like TVs and stereos—get us most excited.

Along these lines, there is now a completely new way to build loudspeakers thanks in large part to nanoparticles. Researchers at Sweden’s KTH Royal Institute of Technology have found a way to eliminate the need for a permanent magnet in stereo speakers by adding metallic nanoparticles to a speaker's membrane.

“This is, to our knowledge, the first reported magnetic speaker membrane,” said Richard Olsson, a KTH researcher, in a press release.

The design of the speaker, which is detailed in the journal of the Royal Society of Chemistry (“Cellulose nanofibers decorated with magnetic nanoparticles--synthesis, structure and use in magnetized high toughness membranes for a prototype loudspeaker”) employs cellulose nanofibers that have had ferrite nanoparticles dispersed evenly throughout the membrane.

The result is a speaker that does not need a permanent magnet to drive the membrane and yet produces a sound quality the researchers argue is as good as, if not better than, traditional speaker designs because of the even distribution of forces within the membrane.

In traditional speaker designs, a voice coil is wrapped around a permanent magnet. The voice coil drives the speaker cone’s movements, which produces the sounds that we hear.

In the speaker design resulting from this latest advance, there is still a voice coil but it is obviously not wrapped around a permanent magnet nor is it directly attached to the cone. Instead, sound is produced solely by the movement of air.

This isn't the first time that nanotechnology has been offered as a possible solution to loudspeaker design.  Five years ago, researchers in China demonstrated how carbon nanotubes could be used to create a transparent loudspeaker film. I have not heard whether anything ultimately ever came of that research.

But if KTH's new speaker technology doesn’t get off the ground, the researchers believe that it has alternative applications in sound cancellation and in one of our other favorite technologies: the automobile.

“We want to look at applications for the material that are driven by magnetic fields. It may, for example, be a form of active damping for cars and trains,” says Olsson in the press release.

Photo: Richard Anderssson

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Digging Into the New QD-OLED TVs

Formerly rival technologies have come together in Samsung displays

5 min read
Television screen displaying closeup of crystals

Sony's A95K televisions incorporate Samsung's new QD-OLED display technology.

Sony
Blue
Televisions and computer monitors with QD-OLED displays are now on store shelves. The image quality is—as expected—impressive, with amazing black levels, wide viewing angles, a broad color gamut, and high brightness. The products include:

All these products use display panels manufactured by Samsung but have their own unique display assembly, operating system, and electronics.

I took apart a 55-inch Samsung S95B to learn just how these new displays are put together (destroying it in the process). I found an extremely thin OLED backplane that generates blue light with an equally thin QD color-converting structure that completes the optical stack. I used a UV light source, a microscope, and a spectrometer to learn a lot about how these displays work.

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