Acoustic Space: Entrance of Bridges Auditorium

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Big bridge spectro


Location: Bridges Auditorium, Pomona College, Claremont, CA

Description of the space: Bridges Auditorium, also called “Big Bridges” was built in 1931 and is located in Pomona College. This building can be described as a “free adaptation of northern Italian Renaissance architecture.” Its exterior design consists of stairs leading to its columns supporting high vaulted arches and three wooden entrance doors. Above the arches, near the top of this building, are five engraved faces and names of the composers: Wagner, Chopin, Beethoven, Bach, and Schubert. If you shout or make a sound louder than a certain threshold, the building right across Big Bridges, Carnegie, will echo your sound.

Recording setup: The recorder and the balloon were both placed about 4 inches above the ground and approximately 6ft apart in front of the center entrance door of Big Bridges.

Reverberation time:

Max intensity: 84.34 dB @ 0.12 sec                                                                                                 30 dB drop: 54.34 dB @ ~ 0.45 sec, took .33 sec after max intensity                                              50 dB drop: 34.34 dB @ ~1.11 sec, took .99 sec after max intensity                                           Back to ambient: 29 dB @ ~1.46 sec, took 1.34 sec after max intensity
Minimum intensity: 27.92 dB, no 60dB drop

Acoustic Description: It is interesting that the balloon pop sounded muffled or dampened in an “outdoor” atmosphere. The sound waves must have significantly bounced off of Big Bridges’s columns, high vaulted arches, and ceiling roof. However, since the microphone was placed facing Marston Courtyard and there was no wall to contain the sound, the sound waves could have escaped to the open atmosphere and decreased the maximum intensity to the point where there wasn’t a 60dB drop. In the spectrogram, there is a slight increase in intensity starting at 9 secs and a faint dark spot around 13.2-13.6 secs This is most likely due to the sounds I made while walking towards the microphone to stop the recording. There was also an airplane or helicopter in the background around that time frame.