A partnership between Cilla Tech Park’s Innovation Center and the Federal Technological University of Paraná has made it possible to print a 3D head that will be used in acoustic measurement research and analysis.
The artificial head for measurements of binaural impulse responses, a term that means having or being related to both ears, was developed by researchers at Trinity College in Ireland in 2021. To have an adapted, innovative and low-cost model, UTFPR’s PhD professor Rodrigo Scoczynski Ribeiro and the UTFPR’s final year Civil Engineering scientific initiation student Eliabe Bento de Almeida turned to the technology park that can help them through the Maker of the CTP’s Innovation Center, Jhonnathan Ferreira.
The 3D head was made with two materials and simulates a human head, with two microphones in each ear that capture the sounds of the spaces. To be produced in real size, the printer with the largest printing area was used, the Cloner 3D, which belongs to the Regional Education Center of Guarapuava, which, in partnership with the Barn, has the printer for training students and state teachers, to foster the culture of innovation. The ears, made of flexible filament so that earplugs, headphones, and other objects can be placed for simulations, were printed on the CTP’s Ender printer.
Jhonnathan and Eliabe worked together to produce the 3D head according to the needs of the research. “Eliabe already brought the pre-molded head, it was already a downloaded SDL (Simple DirectMedia Layer, free and open source multimedia library), they had already placed the pins of the right size of the microphone, but they didn’t know how to do the modeling to place this microphone inside the head and make this adaptation, having this information I made the model with these pieces that he brought already measured and from them I created a model to be printed on the Cloner,” explained Jhonnathan.
The objective of the 3D head is to analyze the sound of environments. In the tests it will be placed in different spaces with a noise emitter. By moving the head around, it will be possible to understand how the sound propagates in that space and to understand if students who sit at the back, for example, can understand the sound in the same way as those who sit next to the teacher. “The microphones will receive the sound part inside the head, to simulate as closely as possible a human being. The head will be used for binaural tests, where the head receives the signals through the two ears and the sound goes to the computer where it is possible to analyze the sound frequencies and the acoustic waves that happen in the environment,” says the academic Eliabe.
These analyses are important, according to Eliabe, because each environment, depending on how it is laid out and the materials it contains, can change the sound frequency, making people understand or not what is being emitted. In the case of children who are learning to write, hearing the wrong sound can hinder the learning process.
The head will not only be used to analyze classrooms. According to Professor Doctor Rodrigo, any place where sound needs to be understood, such as theaters, cinemas, hospitals, among other spaces, will be able to be analyzed. It is also possible to carry out speech intelligibility tests and research related to the speech therapy area. Another possibility is to use the data captured by the 3D head to analyze, for example, how a song would sound inside a theater. “The binaural impulse response allows artificial sounds to be created through digital signal processing, and when listening to these sounds in a headset, for example, the idea is that you get a feeling of how you were in an environment in which the artificial head was recorded. Imagine being able to listen to a song played in the Guarapuava municipal theater without having to be in the theater?”, Rodrigo instigates.
The project is already being put to tests and will receive another 3D piece, produced by the Innovation Center maker, to make the angle of the head every five degrees, improving its use.
Projects and partnerships like these, strengthen the purpose of the Innovation Center of Cilla Tech Park, which is to expand the vision that the community has in relation to the use and applicability of 3D printers, the pedagogical, scientific and entrepreneurial look that they enable. We need to promote the numerous possibilities of using 3D modeling and printing, so that more and more people know how to use this technology that provides innovative solutions and a creative economy, enabling better futures for society.
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