4. Compare the background noise spectrum by third-octave band obtained with the sound level meter and with the smartphone (A-weighting). Are the levels the same? Comment.

5. Analyze the spectrum by third-octave band obtained with the sound level meter for pink noise in the echo chamber: what is the general appearance expected for the spectrum of pink noise? What can explain the difference between the real measurement and the theoretical spectrum?

6. Compare the third-octave band spectrum obtained for pink noise with the sound level meter and with the smartphone (include the graph, pay attention to the weighting used). Does measuring using a smartphone seem acceptable to you? 7. Compare the power spectral density obtained from cell phone measurements in the anchoque room and in room A108, 1 m and 2 m from the source. What are the differences observed between the results of the two rooms? How are they explained?

8. What is the best weighting and filtering to obtain the sound level perceived with a sound level meter? What effect does this sound have on sleep?

9. Make measurements on the telephone of the sound of the two speeds. Which figure on VSLM gives the best information about fan behavior? Compare the two speeds and comment.