Sistema de medida de parámetros acústicos mecánicos y eléctricos de fuentes de infrasonido y baja frecuencia

This research aims to design and implement a source of infrasound and low frequency, in addition to a system of measurement of acoustic, mechanical and electrical parameters, to corroborate employing impedance measurements and frequency response design theoretical with practical implementation. For this, a driver with characteristics capable of reproducing very low frequencies was used. For the application of the measurement system, an analysis of the operation of equipment that performed similar operations was carried out and replicated within an algorithm in Matlab. In addition to this, a connection plate was made capable of interconnecting the output of an amplifier to the input of an audio card and the terminals of an acoustic driver. The algorithm was able to reproduce tones with a frequency range between 1 Hz and 20 kHz, in addition to emitting the signal that passes through the amplifier and reaches the driver, processes the audio card recordings and delivers us to Impedance curve in module and phase of the infrasound source and low frequency. The infrasound source was designed based on previous studies on the impedance in tubes and transmission lines, simulations of a rigid piston adapted to a tube were also taken as reference. The source was adapted to an acoustic box capable of ideal volume to simulate outdoor behavior, in addition to an 8 meter transmission line with transverse dimension variations, which fulfill the function of adaptations to be inserted into the human ear. The source met the requirements and was able to reproduce low frequencies at a level of 140 Db with attenuations of 10 dB at odd frequencies. In turn, the harmonic distortion of the source is acceptable, so it does not generate frequency alterations in the emitted tones.