Automatic Sound Level System : Constant volume at all times

Sammanfattning: Studies have shown that music has plenty of positive effects on performances in working environments. The purpose of this project was to reap those benefits by developing a prototype that could automatically adjust the volume of a speaker. The prototype was also able to measure the total sound level in the surrounding environment. It would then regulate the speaker’s sound level in accordance with the measured sound and a desired volume set by the user. The main focus was to measure, filter and calibrate sound and to develop a regulatory system that could control the volume of the sound system. The final prototype had a user interface with an LCDdisplay and buttons. It had the ability to successfully measure the sound and its amplitude. Calibration of the sound sensor was done using two reference microphones. Measurements at eight different sound levels were taken. A model to convert the digital signal into decibels was then calculated through linear regression with a standard error of 2.9 dB. With this model the prototype could automatically adjust the volume of a Marshall Kilburn speaker to the desired level of 90 dB in approximately 40 seconds. It was found that the largest limiting factor was the sensor’s ability to pick up different sound sources at longer distances from the sensor. Further work may include optimizing the microphone and making an integrated product that can be applied to any sound system.