Abstract:
A research about determination of radiation pattern of sound intensity inside and outside of a room has been carried out. The source of sound used in this research was a Sweep Function Generator. In order to direct the sound it was used 3 types of funnel, namely funnel I, II, and III. The measurement of sound radiation pattern was done as a function of angle from 0o until 90o and frequency of the sound selected from 100 Hz until 2000 Hz. Intensity of sound radiation was recorded using a Sound Level Meter (SLM). The measurement of sound intensity was recorded from the distance of 2 m from the funnel. The result of this research showed that the sound intensity with the angle of 10o produced a maximum value. Increasing the angle of measurement resulted a decrease of the sound intensity. The measurement of sound intensity inside the room using a funnel type I resulted a maximum intensity for frequency of 500 Hz while with for frequency of 2000 Hz produced decreace in intensity and it’s minimum value at 100 Hz. The difference in intensity for these frequency is was due to sound interferences. Maximum value of intensity at frequency of 500 Hz was due to constructive interference. While for frequency of 2000 Hz, the intensity became decrease due to semi destructive interference. For the measurement of sound intensity outside the room, the intensity of the sound was 70 dB which was smaller than that of inside the room
