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using ClapIR
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AUDITORUIM/THEATER PETA-PHINMA Theater
MEASURED REVERBERATION TIME
The proponents used the application ClapIR in measuring the reverberation time inside the PETA-PHINMA Theater. With a corresponding distance per clap, the reverberation time is measured. The first distance is from 5 feet from the sound source or the clap. And the distance between the first point of measurement to the second point is 15 feet. The proponents only measured a total of 4 claps and get the total average of reverberation time measured to be compared to the computed reverberation time.
Measuring the reverberation time using the ClapIR application
Distance from the sound source (clap) : 5 feet
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AUDITORUIM/THEATER PETA-PHINMA Theater
Distance from the sound source (clap): 20 feet
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AUDITORUIM/THEATER PETA-PHINMA Theater
3
AUDITORUIM/THEATER PETA-PHINMA Theater
Distance from the sound source (clap): 35 feet
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AUDITORUIM/THEATER PETA-PHINMA Theater
Distance from the sound source (clap): 50 feet
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AUDITORUIM/THEATER PETA-PHINMA Theater
As the proponents finish the measurement of reverberation time in a particular distance, the proponents analyze the data and come up with the table below. The table consists of the claps from the distances inside the PETA-PHINMA Theater.
Distance (feet)
Reverberation Time
(seconds)1st Clap 5 feet 1.53 seconds
2nd Clap 20 feet 1.49 seconds
3rd Clap 35 feet 1.22 seconds
4th Clap 50 feet 1.15 seconds
Measured Reverberation Time Table
The proponents get the average reverberation time to be used for the comparison of the measured and the computed value.
Average RT60 (Measured )=RT1+RT2+RT3+RT 4
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Average RT60 (Measured )=1.53+1.49+1.22+1.15
4=1.3475 seconds
REVERBERATION TIME COMPUTATION
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AUDITORUIM/THEATER PETA-PHINMA Theater
Given:
Volume (empty) = 2426.841
Volume (full) = 2092.5
Surface Area (S) = 1160.42
Absorption Coefficient Full (α) = 0.267
Absorption Coefficient Empty (α) = 0.287
r ( orchestra ) = 5
Computation for Ideal RT60:
Using the Stephen and Bate Equation
Computation for Ideal RT60( Empty):
Ideal RT60 (empty )=r (0.012 3√V empty +.1070 ) Ideal RT60 (empty )=5 (0.012 3√2426.841+.1070 )Ideal RT60 (empty )=1.34786 secs
Computation for Ideal RT60( Full):
Ideal RT60 (empty )=r (0.012 3√V Full+.1070 ) Ideal RT60 (full )=5 (0.012 3√2092.5+.1070 )
Ideal RT60 (full )=1.30243 secs
Computation for Computed RT 60:
Using the Norris - Eyring Equation
Computation for Computed RT 60(Empty):
RT60 (Empty)=0.161V Empty
−S ln (1−α Empty)
RT60 ( empty )=0.161 (2486.841 )
−(1160.42 ) ln (1−0.287 )
RT60 ( empty )=1.2754 secs
Computation for Computed RT 60(Full ):
RT60 (Full)=0.161V Full
−S ln (1−αFull)
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AUDITORUIM/THEATER PETA-PHINMA Theater
RT60 ( full)=0.161 (2092.5 )
−(1160.42 ) ln (1−0.267 )
RT60 ( full)=0.9347 secs
PERCENTAGE DIFFERENCE
Given:
Computed RT 60( empty )=1.2754 secs
Computed RT 60( full )=0.9347 secs
Measured RT60 (empty )=1.3475 secs
Computation for Empty:
%Diff =Measured RT60 – Computed RT60 (Empty)
Measured RT 60
×100
%Diff =1.3475 secs –1.2754 secs1.3475 secs
×100
%Diff =5.3506%
Computation for Full:
%Diff =Measured RT60 – Computed RT60 (Full)
Measured RT60×100
%Diff =1.3475 secs –0.9347 secs1.3475 secs
×100
%Diff =30.6345%
COMPARISON OF RT60 COMPUTED TO THE MEASURED VALUE OF RT60
The proponents measure the Reverberation Time inside the PETA-PHINMA Theater. And for
the computation of the empty room the proponents sum up all the value of the absorption
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AUDITORUIM/THEATER PETA-PHINMA Theater
coefficient of the flooring, ceiling, walls and other miscellaneous material and divides it by the total
number of materials, and the proponents get the value of alpha which is equal to 0.237 for empty
room and for full capacity the value of alpha is 0.267, that is why in solving the RT60 the
proponents used the formula of Norris-Eyering because the value of the alpha that the proponents
get is greater than 0.2 which is the requirement for Norris-Eyering equation.
As the proponents gathered the data, the proponents computed the value for full and empty
room. By solving simultaneously the value of the RT60 of a full room is 0.9347 seconds, which is
slightly close to the average measured Reverberation Time of 1.3475 seconds which gives us
30.6345% by using the percentage difference. Lastly, for Empty room the value of RT60 is
approximately 1.34786 seconds which is close to the average measured Reverberation Time of
1.3475 seconds which gives us 5.3506% error.
The proponents compared the measured value to the ideal value of the Reverberation time for
empty room which is 1.34786 seconds using the Stephen and Bate formula. And for the full
capacity the ideal reverberation time is 1.3024. The measured value is somewhat close to the ideal
reverberation time. And therefore the proponents conclude that the design of the room is for
acoustic purposes.
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