It's one thing to assemble a loudspeaker from 3D-printed components, but researchers at Disney have figured out a way to 3D print interactive loudspeakers in any shape imaginable, while also integrating speaker functionality into the whole object or just parts of it. Just envision 3D printing an entire loudspeaker in one step in the shape of Cinderella, and having sounds boom off her whole body or just her skirt.

From a rubber duck to an abstract spiral, the small loudspeakers 3D-printed by the Disney team reproduce sound to about 60 decibels and run off batteries. According to the scientists, these speakers can faithfully reproduce high frequency sounds like those made by stringed instruments, birds, people, other animals, and computer-generated blips. They're less effective when it comes to low-frequency sound playback. Inexpensive to make, the speakers are based on electrostatic speaker technology and have no moving parts.

Each loudspeaker contains an electrode plate and a thin conductive diaphragm, separated by a layer of air. When a high voltage audio signal is applied to the electrode, the diaphragm deforms and reproduces the sound. Currently, the prototypes still require a little manual work and assembly (the conductive surfaces are created by spraying on a nickel-based conductive paint), as there aren't any multi-material 3D printers capable of printing with conductive inks.

"In five to 10 years, a 3D printer capable of using conductive materials could create the entire piece," says Yoshio Ishiguro, a Post Doctoral researcher at Disney Research.

It's safe to pick up these speakers, as the grounded diaphragm protects users from the high-voltage audio signal; handling them when they are in use doesn't affect the sound quality either. Adding loudspeaker functionality to either parts of objects or converting their entire surface into a loudspeaker is also possible, the researchers claim, as it's a matter of augmenting them with 3D-printed diaphragms.

For instance, the spiral speaker prototype contains a 3D-printed diaphragm that's attached to the speaker body with a silicone compound, enabling it to transmit sound off its flat surfaces. To make a duck speaker that could emit sound off its whole body, the team developed a new fabrication technique using negative molds to create full-body-compliant diaphragms. The strong, thin diaphragm that they were able to make mirrors the duck's shape and covers its whole body, turning its entire surface into a speaker.

All these manual steps can be eliminated, the researchers state, once multi-material 3D printers capable of printing functional electrical circuits and electrodes are developed.

It's also possible, the researchers say, to 3D print omnidirectional speakers and directional cone-shaped speakers, as developers can control the direction of the emitted sound by controlling the speaker's shape and electrode arrays.

Since these 3D-printed speakers can also produce inaudible ultrasound, it's possible to identify and track them, paving the way for their use in novel interactive applications such as storytelling. For instance, if a person brings the 3D-printed duck speaker closer to the microphone of a computer that's running the storytelling software, the software can detect the ultrasound signal, decode the character ID and animate the appropriate cartoon character on screen.

The Disney team's goal is to make the 3D-printed speakers so simplistic that designers can pick and drop speakers into devices and objects in the design phase, as additional elements in their computer-aided design (CAD) programs. They plan to investigate techniques for 3D printing very large speakers and speaker arrays next.

Developed by Ishiguro and Ivan Poupyrev, a former Disney Research Pittsburgh principal research scientist, the technology was recently presented at the Conference on Human Factors in Computing Systems (CHI) in Toronto, Canada.

Check out a video of the technology below

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