Same object, different sound thanks to acoustic voxels

3D-printed motorcycle earmuffs that suppress traffic and wind noise while amplifying car horns, and objects encoded with one-of-a-kind audio barcodes are only a couple of the devices that may be on the way, thanks to a new system created by researchers at Columbia University, MIT and Disney Research that allows for specific acoustic properties to be implanted into 3D-printed objects.

“With 3D printing equipment currently, geometric harshity is no longer a barrier,” says Changxi Zheng, the Columbia Engineering researcher major the project. “Even harsh shapes can be fabricated with quite little effort. So the question is: can we use harsh shapes to improve acoustic properties of products?”

“Acoustic voxels” are the core of the system. These are hollow cube-shaped chambers that can filter sound waves according to their dimensions, shape and the way they connect to every other. With the assist of a new algorithm, harsh structures of these modules can be set up to create the desired acoustic filtering consequences, that can be embedded inside 3D-printed objects.

“The general approach to manipulating sound waves has been to computationally create chamber shapes,” says Zheng. “Our algorithm empowers new creates of noise mufflers, hearing aids, wind instruments, and additional – we can now manufacture them in any shape we want, actually a 3D-printed toy hippopotamus that sounds like a trumpet.”

Those toy hippo trumpets can appear familiar: Disney researchers demonstrated much like-appearing 3D-printed speakers a couple of years ago that created use of the acoustics of any shape, but this new research takes a quite various approach.

The acoustic voxels system can be embedded into an object regardless of its shape, so two toy octopi can appear identical on the outside, but have vastly various acoustics when tapped or blown into. That system can lead to objects with one-of-a-kind audio signatures.

“We in addition have proposed a quite interesting new way to use acoustic filters,” says Zheng. “We can use our acoustic voxels as acoustic tags, one-of-a-kind to every piece we 3D print, and encode information in them. This is much like to QR codes or RFIDs, and opens the door to encoding product and copyright information in 3D printing.”

Voxel structures may in addition be created to suppress or amplify specific frequencies, major to additional efficient engine mufflers, or motorcycle earmuffs that may decrease traffic and wind noise but allow the sounds of honking cars to get through. In future, ultrasound waves are the future target for the project.

“We are investigating a few of the interesting possibilities of ultrasonic manipulation, such as cloaking, where sound propagation can be distorted to hide objects of sound waves,” says Zheng. “This may lead to new creates of sonar systems or underwater communication systems. It’s an amazing area to explore.”

The team explains the project in the video at a lower place, and can present the research at the SIGGRAPH 2016 conference future week.

Source: Columbia Engineering