Caracterização de microfones no espaço tridimensional utilizando o método Time-Stretched Pulse

Abstract

Transmitting messages, providing comfort, and producing immersive sensations to the listener, are some of the challenges faced by professionals who dedicate their lives to the audio field. This theme involves many subjective aspects, however, acoustic characteri-zation is widely used when it is necessary to quantify these aspects, making it possible to measure the quality of the sound and equipment involved in a project. Using an au-tomated platform and a modular support, this work aims to characterize microphones, taking into consideration the three-dimensional space, generating spatial 3D pickup pat-terns, measuring impulse responses, and determining frequency responses. Using a plat-form controlled by LabVIEW with a Texas Instruments development kit TIVA, it was possible to automatically measure in 360° azimuth the incidence sound on the micro-phone. A support, projected and manufactured in a 3D printer, was use to characterize the microphone elevation. The azimuth and elevation variations, when combined, cover the three-dimensional directions of the sound incidence around the microphone. With the Time-Stretched Pulse method, an audio signal capable of covering the desired frequency range was created. This signal, when reproduced and later processed with its inverse filter provides the necessary information to describe and highlight the behavior of the Boya Ml, BM800 and Behringer Xm1800s microphones.