ME458 Lab 3 8/17/2000 page 1
ME458 Noise Control
Laboratory Exercise #3
Reverberation Time
Objectives:
Determine the reverberation time of several rooms by direct measurement and by calculation.
Part 1: Reverberation Time of the Reverberation Room
Determine the reverberation time of the Reverberation Room in octave bands from 125 Hz to
2000 Hz using two different methods and compare the results:
1) Determine the room constant R using the calibrated ILG source, then calculate T60
2) Direct measurement: measure the decay of sound T60 using the Norsonic analyzer.
Frequency
Hz ILG Source
Lw ILG Source
Lp Room
Constant R Reverb time
T60 from R Measured T60
125
250
500
1000
2000
Part 2: Reverberation Time of our Classroom
Measure the reverberation time for our classroom and compare to calculations based on the
construction materials used.
Frequency Hz Calculated αS Calculated T60 Measured T60
125
250
500
1000
2000
Calculations of room absorption from construction materials and room dimensions:
Surface Name Material Area α αS
Total
Reference for absorption coefficients:
Reporting Requirements: Submit a brief, concise lab report, include: Cover page, data
tables, list of instrumentation, calculation details, comments, conclusions
