Category Archives: Reverberant Spaces

Bridges Auditorium Main Lobby

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Big Bridges Main Lobby

Very reverberant.

30dB decay: 1.7 seconds
50dB decay: 3.4 seconds
The recording was truncated before a 60dB drop was reached.

Recording by Justin Dixon

Stage in Frary Dining Hall (Pomona College)



Location: Frary Dining Hall Stage at Pomona College

Description of the space: Frary Dining Hall is the largest dining commons at Pomona College. It is an enclosed building with high ceilings and wooden furniture. There is also a large stage at the west of the building with a three steps leading up to it. The ceiling in this specific stage is a little domed-shapes and a feel ridges. The bottom half of the stage is wooden, and the upper half is painted wood. There is also a fireplace at the center of the stage that is about 8 feet wide and 8 feet tall.

Recording Setup: The balloon and microphone were placed at the same level of about 4 feet high off the stage floor at the center (in front of the fireplace). The balloon pop and microphone were about 3 feet apart from one another.

Reverberation Time:

20 dB decay: 1.4 sec

40 dB decay: 3.06 sec

(via Praat)


Acoustic description:

Cindy Duong & Amanda Martinez

Pomona Skyspace Reverberant Space

Location: Dividing the Light skyspace installation, west side, Pomona College, Claremont, CA

Description of the space: The Skyspace is a permanent architectural installation by James Turrell consisting of of a square courtyard enclosed by metal columns surrounded by palms and ferns, and encircled by the Lincoln-Edmunds academic building. The roof of the space has a square opening in the center to allow viewing of the sky. There is a large square fountain

Recording setup: The balloon was placed approximately two feet from the west edge of the central fountain, three feet above the ground, with the microphone placed at the same height three feet away from the balloon.

Reverberation time:
30 dB decay: 0.3 sec
40 dB decay: 0.6 sec
Decay to background level: 0.4 s
Minimum: 3.6 s

Acoustic description:

The balloon pop provides an interesting picture of the Skyspace’s reverberance. The pop seemed to have a certain richness to it–a richness that would not be present if the space was fully enclosed. This semi-enclosure in terms of walls and other hard surfaces being present, but spaces open to the outside also being present led to a unique auditory perception of the space. The sound was also scattered by various small objects, like the benches. Moreover, not only did the sound of running water underlay the balloon pop itself, but it was also evident in the reverberation. In essence, an integral part of being inside the Skyspace is noticing how sounds (from the water and otherwise) reverberate, and this characteristic was made particularly evident from the balloon pop.



Acoustic Space: Coop Fountain

LocationFront of Coop Fountain. Located in the first floor of the Smith Campus Center. Pomona College, Claremont, CA.

Space Description: The Coop Fountain in the Smith Campus center is a normal-sized establishment. It is comprised of two rooms, divided by a wall, used as a display, that almost separates the two completely. Each room has a set of booth-style tables, chairs and tables. Located at the front of the restaurant is the kitchen and grill. The back of the restaurant includes the office of the general manager. The sides of the establishment are covered in windows and doors. The recording took place at 3:15 PM on September 14, 2018.

Recording Setup: The balloon was blown up to about 18 inches and held about 4′ off the ground, and about 3′ away from the recording device. The balloon itself was held outside the Coop Fountain , next to an open door where the recording was on the other side of the open door, inside of the establishment.

Reverberation time: 

Total drop: < 30dB

25 dB decay: 1.1 sec

Acoustic Description: The Coop Fountain in the Smith Campus center is a open establishment, where sound travels throughout. There are not any areas where an echo of any sort is really present or prominent. The openings along wall that separates the Coop into two rooms, allows sound to travel seamlessly throughout the establishment. The Coop Fountain derives its sound mainly from its metallic doors, general kitchenware and background music; all of which layer themselves on top of each other and forces listeners to hear each sound individually in order to uncover them  all.

Marie Tano and Luena Maillard


Pendleton Dance Studio, Pomona College

Center of the dance floor in Pendleton Dance Studio, Pomona College, Claremont, CA.

Description of the space:
The Pendleton Dance Studio is large and open with a high pointed ceiling, and the walls block out sound from the outside. One wall is completely covered in mirrors, one wall is covered in windows showing to the pool outside, and the floors are made of wood.

Recording setup:
The microphone and balloon were held at the center of the dance floor, about three feet apart.

Reverberation Time:
30 dB decay: 0.5s
60 dB decay: doesn’t reach
decay to background level:
minimum: 1.9s
(Analyzed using intensity graph function in Praat)

Acoustic description:
Sound in this space quickly drops and is deadened by the same thick walls that keep out sound. Sound drops 30db in 0.5s, almost as quickly as it arrived, and it continues to drop as quickly until it is at the level of its usual background noise. This keeps echo and residual hum to a minimum, probably an intentional move by the designer of the space, since overlapping sounds of dancers moving across the floor would detract from the more visual qualities of it.

The Cube at Claremont McKenna College

The Living Room, commonly referred to as “The Cube” is a silent study space on Claremont McKenna’s campus. The room has tile floors and is surrounded by glass walls and floats on a Mesabi black granite reflecting pool in the middle of the Kravis Center. The Cube is filled with comfortable armchairs and couches for students to do work in.

Recording Setup: The microphone and balloon were both held about five feet off of the ground in the center of the Cube, while no other students were in there (as not to disturb the silent study space). The balloon was popped about four feet away from the microphone.

Acoustic Description: The resonance of the space is likely attributed to the enclosed tile floor and glass walls. The balloon pop showed a 20dB decay after .6 seconds and a 40dB decay after 2.8 seconds.

Reverberation Time:

30 dB decay: 0.6 seconds
minimum: 2.8 seconds

Erin Burke and Kat Burgstahler

Bosbyshell Fountain

Description of the Space

Bosbyshell Fountain is located in Bixby Plaza, the courtyard just outside Frary Dining Hall at Pomona College. The fountain was flowing at the time of recording, which is why the sound does not reach -60 dB.

Recording Setup 

The recording was done with the TASCAM DR-40 Sound Recorder placed on a nearby bench. The 18-inch balloon was popped approximately 5 feet away from the recorder and approximately 5 feet off the ground.

Reverberation time:

30 dB decay 0.6 seconds

40 dB decay: 0.8 seconds

Minimum: 0.9 seconds

Acoustic Description:

This is an open-air area with no walls. There are some trees, and most of the ground is paved, but some is earth. Consequently, the sound decayed quite quickly, but the background noise level was relatively high due to the sounds of the flowing fountain. The sound graph shows several echoes, most prominently (and audibly) at about 0.18 sec.


Posted by Hervé Iradukunda (PO) and Eli Fujita (PZ)

Lyon Court Staircase


This balloon pop was taken October 31st, 2018, at 5pm. The location, Lyon Court stairwell, consists of brick and cement walls, with two linoleum covered stairways converging in a triangle at a carpeted landing, which then bifurcates into two similarly carpeted hallways. The ceiling stands approximately 7m above the bottom stair, and the stairway itself is only approximately 1.5m wide. Only one of the outer wooden doors was closed at the time of recording.

Acoustic Data:

Maximum: 87.44dB

Time to drop 30dB: 0.5s

Time to drop 60dB: 3.98s (Only dropped 58dB)

Minimum: 29.4dB


Recording Process:

Blew up balloon to a radius of ~.25m. Balloon was held about a meter from the ground, and 0.6m from the TASCAM recorder. Key was used at first but to no avail, scissors were used after to successfully pop the balloon. The sound was collected from the bottom of the east stairwell.

Acoustic Analysis:

The longer reverberation time can be explained by the large amount of vertical open space as well as the narrowness of the stairs. Additionally, the hard linoleum finish on the stairs and the brick and cement walls could have added to the amount of reverberation, and consequent 30dB drop time. The graphs above show that the sound does not totally drop 60dB, which may be understood by the fact that a residence hall such as Lyon is subject to background noise, and the hallways above the landing could have continued to propagate the sound wave.  

by Thummim Mekuria and Daven Crossland

Frary Walkway

Location.  Walkway spanning the distance from Frary Dining Hall to College Way, midway between Walker and Clark V student dormitories. Pomona College, Claremont, CA.


Description of the space.  The walkway is wide, with a few trees, picnic tables, and small lawn spaces flanking both sides (in front of the dormitories). Small, unpaved pathways branch off the main walkway and lead to the entrances of each dormitory. The area is usually occupied by any number of students; however, because the recording was taken at a later time of night, the area and its soundscape have a fairly subdued quality. Beyond the stretch between the two dormitories, the area surrounding the walkway is generally open.


Recording setup.  The microphone and balloon, approximately 3 feet apart, were held at 4-5 feet from the ground. The microphone (a TASCAM DR-40 recorder) was supported by a tripod, and the balloon was held manually.


Reverberation time.

30 dB decay: 0.4s

60 dB decay: Not measured

decay to background level: approximately 0.8 sec, although hard to tell with the background noise. 

minimum: 0.8 sec

Acoustic description.  The resonance in this space is barely perceptible, due to the relatively open area in which it was recorded. However, likely a result of the buildings that hem the walkway on both sides, a faint echo is audible at approximately 0.8,1.4, and 1.6 seconds. These reverberances are visualized as (faint) vertical bands on the spectrograph.

Posted by Yannai Kashtan and Jeanne Rasmussen

Wilbur Courtyard

Location: The Wilbur Courtyard is a small outdoor space. It is enclosed by four walls on adjacent sides, but there is no ceiling enclosing the space.

Recording Setup: The microphone and balloon were placed on the concrete floor of the courtyard.

Reverberation Time: 0.1 seconds

Maximum Intensity: 80 dB

Minimum Intensity: 60 dB

Acoustic Description: Unfortunately, the space has little reverberant qualities. I believed the space would be more reverberant due to the enclosing four walls. But it seems like the open ceiling allows the sound to escape and prevents the sound from reverberating against the walls. Additionally, our recording has a lot of wind which made it difficult for Praat to calculate when the pop occurred and when the sound drops. The image above illustrates how a lot of wind disrupts much of the recording and a 30 dB drop doesn’t seem to occur.

Stairwell in Thatcher Music Building



Location. Stairwell leading from first-floor lobby to basement of Thatcher Music Building, Pomona College, Claremont, CA.

Description of the space. It is an enclosed two-flight staircase. The walls, which include a wall separating the two flights of stairs, are of painted concrete. The steps and landing are covered in laminate tile and appear to be concrete underneath. The stairwell has doorways at top and bottom, usually open, for entry and exit. They were open during this recording. The ceiling is at an angle, so that the distance above any step is approximately approximately ?? feet. Total height of the stairwell from the bottom landing to the ceiling above the top landing is approximately ?? feet.

Recording setup. The microphone and the balloon were both placed near the floor of the landing between the two flights of stairs, about three feet apart.

Reverberation time.
30 dB decay: 1.8 sec
60 dB decay: 4.8 sec
decay to background level: 5.0 sec
minimum: 6.4 sec
(Analyzed using intensity graph function in Praat,)

Acoustic description. The resonance in this space prominently reinforces a pitch that I hear as the E-flat just above middle C. This pitch becomes audible as a hum less than a half-second after the pop, and it remains perhaps the most prominent feature of the sound for about two seconds. It is visible in the form of a dark band  running across the spectrograph at about 312 Hz. Also, the reverberance of the stairwell produces a vibrato- or tremolo-like effect that is visible in the spectrograph’s striated low-frequency band.

Soundscape: Peter W. Stanley Quadrangle

Pomona College -Peter W. Stanley Quadrangle -


Location: This recording was done right next to the fountain in the Peter W. Stanley Quadrangle. 

Recording Setup: (Recording device: TASCAM-40). Recording was done done right next to the fountain in the Peter W. Stanley Quadrangle. 

Description: The quad is a open space, with multiple entrances. The quad is also flanked by three academic buildings. The quad acts as a garden and courtyard space between these three academic buildings. In the recording, which was done in the afternoon, records the fountain, the centerpiece of the quad. The most relevant part of the recording is the constant running of the water.

Reverberant Space: Bridges Hall of Music


reverb-Pomona-Little Bridges -Front Stage

Location: Bridges Hall of Music

Description: An 18” balloon was popped and recorded using a TASCAM DR-40 sound recorder. I stood in the center of the the stage at Little Bridges  and popped the balloon while Profesor Cramer recorded the event with the microphone about 3 feet from the balloon and pointed in its direction.

Reverberation time

30 dB decay: 0.3s

60 dB decay: 1.7s


Reverb – Drinkward Recital Hall, Harvey Mudd

reverb-Harvey Mudd-Shanahan Building-Drinkward Recital Hall




Drinkward Recital Hall, Harvey Mudd College

Description of Space:

The recital hall can hold an audience of 100 people. The walls of the recital hall are padded well to make the hall an intentionally reverberant space. The ceiling is about 50 feet high. The floors and walls have a wooden finish.

Recording Setup:

The recording was made with the TASCAM DR-40 Sound Recorder placed on a tripod on the podium in the recital hall. The balloon was popped about 5 feet away from the recorder, in the center of the stage.

Reverberation time:

30 dB decay 0.5 second

50 dB decay: 1.1 second

Decay to Background Level: 1.5 second

Minimum: 1.6 second

Acoustic Description:

The walls of the hall were padded, which resulted in a relatively lower amount of resonance. However, the pop sound itself is very clear. The sound did not take too long to die down, and there wasn’t much echo.

Hoch Shanahan Dining Commons, Harvey Mudd, March 4th, 12pm

Harvey Mudd-Hoch Shanahan Dining Commons-Chef counterLunch time



This recording was made at the Harvey Mudd Dining Hall, Hoch Shanahan Dining Commons during lunchtime. There are four big food stations at the Hoch, and this recording was taken at one of them. The food stations are one of the busiest parts of the dining hall. This is where the chefs and the students communicate. The students stand in long lines and socialize. This audio recording captures the soundscape of the peak lunchtime hour at Harvey Mudd: 12pm.


This recording was made using the TASCAM DR-40 Sound Recorder. The recorder was placed on a tripod and then on the counter of one of the chefs.


There are no major events in this sound recording, therefore non are marked on the diagram. However, the three main elements of this soundscape are the plates/utensils, the students and the dining hall staff. Throughout the recording, the sounds of plates and utensils hitting each other are the most noticeable. Some of the sounds are more distant, indicating that these are sounds coming from the kitchen/behind the counter. Speech is heard from students in English and some speech is heard from the dining hall staff in both English and Spanish. The interesting aspect of this soundscape is that there is constant commotion and noise in the dining hall. Additionally, the two audible sentences presumably from students both use the common phrase: “It’s lit”. A student says “lit, fam” at the 0:08 mark, and another student says “lit” at the 1:51 mark. While this might just be a coincidence, it is interesting to hear a commonly uttered phrase twice in the dining hall soundscape in a two minute recording.


Soundscape: The Wash

Pomona College -The Wash -

Location: The recording was done right next to the entry of the Pomona College Farm on Amherst Street.

Recording: TASCAM recorder

Soundscape: That afternoon, it was a clear, sunny day. In the background, there are automobiles passing by. There are also birds chirping in the tress and the wind is blowing. Also, if you listen closely, there are chickens clucking in the distant background. Since the recording took place near the outskirts of campus, there is no dialogue.

Balloon pop – GSC


reverb-Pitzer-Gold Center



Location and recording description:

This version of the balloon pop took place at the Gold Center on Pitzer campus. It was an oblong, medium-sized room which surprisingly was pretty reverberant. It was also on the second floor, so other noises seemed less present in the recording. The balloon was placed 2-3 feet away from the recorder. The decay as shown by the graph seems relatively steady to me, although while recording it did not; it’s possible the initial noise seemed to detract from the overall progression of audio.

Platt Music Practice Room






Music practice room found in Harvey Mudd College’s Platt Campus Center.


Description of Space:

The practice room is a small room, about 7 ft by 10 ft, that has sound-reducing padded walls. The space contained a few chairs, as well as a book shelf and a piano on one side of the room. The floor is carpeted, and the walls have a kind of carpet on them as well.


Recording Setup:

The recording was done with the TASCAM DR-40 Sound Recorder placed on a short tripod on top of the piano, facing the middle of the room. I stood 6 feet from the recorder holding the recorded 18-inch balloon roughly 5 feet above the ground.


Reverberation time:

30 dB decay 0.32 seconds

50 dB decay: 0.72 seconds

Decay to Background Level: 2.98 seconds

Minimum: 3.64 seconds


Acoustic Description:

The padded walls of the practice room cut down on resonance, as the walls tend not to vibrate with the sounds, but they seem to add some reverberation, as can be seen by the second peak after the balloon pop at roughly 0.02 seconds. This is very soon after the pop, but it shows an echo of some sort all the same. The sound took a relatively long time to decay as it remained in the room throughout the recording.

Reverb – My car – cadillac ats – backseat

reverb- my car - cadillac ats - backseat - spectogram



cadillac ats photo

Space Description: My car is a mid-size sedan. It is a very small acoustic space that is enclosed very tightly. The seats are leather with a seating capacity of 5. The overall length is 182 inches and the width is 71 inches. The height is 56 inches. Car is made of steel, copper, aluminum, and copper body panels with plastic and rubber interiors. Also there are glass windows on the car.

Recording setup: I placed the TASCAM DR-40 Linear PCM on the front dashboard of my car, standing vertically. The balloon was placed in the backseat of my car.

Reverberation time:

Max: >100 dB

-30 dB: .07 seconds

-60 dB: .2 seconds

Minimum: 18.5dB after .5 seconds

Acoustic Description: The sound of the balloon pop did not linger very long. There was the initial pop, which was very intense due to the small enclosure of the car, and then a rapid decline in decibels followed by a brief echo and then leading to another fast decline in decibels. The physical space of my car was not susceptible to a lot of reverb as the sound died within the car pretty fast. There was one initial loud echo and then the sound died. The outline of the acoustic space is very jagged and asymmetrical with seats, dashboards, and other items jutting out here and there. This probably was a factor for the rapid resonance decrease.

Balloon Pop in the Atrium Outside of the Lyon Court Laundry Room 2/22/17

reverb-Pomona-Wig Hall-Atrium Outside of Laundry Room2:22:17

Space Description: The atrium outside of the Lyon Court laundry room has low ceilings. The entire area in made of hard concrete, so every sound in “boomy”. The atrium has walkways that lead to the courtyard in between Harwood Court and Lyon Court, and to the open space between Harwood and Mudd-Blaisdell, a neighboring dorm. The recording took place at 9:15 PM on February 28, 2017.

Recording Setup: The TASCAM DR-40 Linear PCM was placed on a bench attached to the wall, and was facing towards the walkways leading away. The balloon (approx 18″) was tossed into the air, then popped when it was about 4′ off the ground, and about 3′ away from the recording device.

Reverberation Times:

Max Intensity: 87.5 dB

-30 dB: .796 Seconds

-50dB: 1.737 Seconds

Minimum Intensity: 32.3 dB after 2.6 Seconds

Acoustic Description: Although the atrium itself is fairly closed off, the area around it is very open, so once the sound escapes, there is nothing for it to echo off of. The graph shows that there were not many bumps in the decay. This is because of the lack of echo that the space produces – the sound is amplified due to the enclosure, but the sound is able to escape to where it does not echo.

Acoustic Space: Olin Basement Corridor, HMC


Location: Corridor located within the basement complex of Harvey Mudd College’s academic buildings. The map below shows the exact location of the corridor.


Description of the space: The corridor is approximately 7 ft wide, 9 ft tall, and 90 ft long. The ends of the corridor turn at 90 degree angles and keep continuing. There are doors that are slightly caved in, as well as light fixtures on either side of the corridor which might prevent reverberation. The floor is solid, although a portion of it is carpeted.


Recording setup: The recording was done at the center of the corridor. I held the balloon 5 feet high, approximately 6 feet from the TASCAM DR-40 Sound Recorder which was placed on the floor using a tripod.

Reverberation time:
30 dB decay: 0.6 sec
50 dB decay: 1.3 sec
decay to background level: 2.0 sec
minimum: 3.0 sec

Acoustic description: The resonance of this space does not cause any echoing, as the intensity drop seems to be linear, without any secondary peaks. The decay time is also relatively fast, which could either be caused by the placement of the recorder, or the acoustic properties of the corridor.

Reverb Space: Case Laundry Room




Location: Case laundry room is in the Northeast corner of 1st floor case dorm. It is the only laundry room in the dorm. The room has one door and one window facing Case courtyard. The room is rectangular, with four washers and four dryers lined up along the two longer sides. For this recording, the ballon was placed in the Southwest corner of the room. The recorder was placed on the 3rd washer away from the wall, approximately 5 ft away from the balloon. The recording was done when no washer or dryer was operating. Setup of the recording illustrated in the figure below:

Screen Shot 2017-03-18 at 21.54.08

Reverberation time:

30 dB decay: 0.2212s
50 dB decay: 0.4632s
60 dB decay: 0.8114s
decay to background level: 0.9472s

Peak Intensity: 81.79 dB
Bottom Intensity: 15.81 dB @ 1.6118s

Acoustic Description: The laundry room is an enclosed space with acoustically interesting objects such as full/half-full detergent bottles and sheet metals (found on washers and dryers). The nature of this room gives it relatively damp air that absorbs sound waves and minimizes reverberation. Immediately after the balloon pops, there was audible resonance produced by the sheet metals and/or the plastic bottles; then both the pop and its resonance decreases at a rate that is surprisingly rapid for such a confined space — sounds die off almost as quickly as they would on an outdoor field. The rate of the sound’s decay and the absence of strong echo suggest that the sound vibrations are trapped between the detergent boxes, absorbed by the moisture in the air, or converted to mechanical vibrations of the sheet metals on washers and dryers. The spectrogram shows a persistent, low frequencies sound after the pop (slightly above 30Hz), which might correspond to the vibration of the sheet metals after they receive the shock; however, without further testing we cannot draw definite conclusion on what caused the post-pop low frequency sound. balloonPop

Reverb – Outside Rose Hills Entrance


Recording setup: I placed the balloon in the middle of the floor and placed the TASCAM recording device approximately six inches away and balancing on the tripod three inches above the ground.

About this recording: This balloon pop took place in the echoey area right by the entrance to the Rose Hills Theatre in the Pomona SCC. The ceiling is vaulted and the entire surrounding structure is made of stone, but open entrances on three sides allow outside sounds in (in other words, it is not closed-off.) There is also a set of stairs by the third entrance, which could affect the sound.

30 dB decay: .274 seconds
50 dB decay: 1.7 seconds
60 dB decay: 2.76
decay to background level: 1.79, since there was background noise before

The spectrogram indicates a space that does not enable for an even decay of sound. While the balloon sound indeed does decay at a steady rate, the echoey nature of the location shows that it picks up on barely-audible sounds long after the initial sound has passed. There is a steady level of general background noise on the spectrogram (a gray haze) that overlays the more prominent, audible background noises.

Millikan Bathroom Balloon Pop

reverb-Pomona-Millikan Building-BathroomFeb 25th, 2017

Acoustic Space: Millikan Female Bathroom


Spectrogram (see below)

Waveform (uploaded)

Intensity (uploaded)

Description of the space:

This balloon pop took place in the female bathroom on the first floor of Millikan in Pomona College. The bathroom is not a private stall but a communal one situated right by the staircase and diagonal to the physics lounge. Walking into the space, there is a rectangular area right by the door where the sinks are situated. Then there is a narrow space that extends down where all the stalls are located. The walls of the bathroom are tiled. The balloon pop was done in the middle of the rectangular area.

Recording setup and recording device:

The way it was set up is that after the balloon was all blown up, it was placed right in the middle of the rectangular area. Then, the TASCAM DR-40 sound recorder was placed about three feet away from the balloon on the ground with the tripod attached to it.

Reverberation time:

30 dB decay: 0.368 s

50 dB decay: 0.752 s

60 dB decay: 1.056 s

decay to background level: 3.2 s

seconds until reach minimum: 5.504 s

max intensity dB: 92.069

min intensity dB: 15.0210

Acoustic Description:

Without the balloon and simply speaking in this bathroom, there is an echoic sound in the space. The voice seems clear and crisp and very focused. The sound is not hollow like that in a church space but there is a slight fine echo. The bathroom door was closed was the balloon pop took place. Although the bathroom size is relatively large, the balloon pop sound was still very focused, clean and crisp with a rather loud pop because of the structure. The balloon pop was done in the rectangular area, and this area could “trap” the sound because the other part of the bathroom was a long narrow hallway with stalls sort of like a tunnel. That did not create much opening for the sound and therefore the pop was quite focused in the rectangular area. The sound bounced off the three surrounding walls and did since the other opening was just the tunnel of stalls, there was not much space for the sound to escape. It is interesting because the spectrogram shows that there is a very dominant loud sound in the beginning right at the pop and then the sound rapidly descends. There is a short time a few seconds after the pop that there is a dark grey streak in the spectrogram, but otherwise the pattern seems to be a very high peak at the pop and then a rapid descend.


Acoustic Space: ITS Elevator


Location. This recording was taken inside the elevator of the ITS building across from Edmunds Hall , Pomona College.

Description of the Space. To the left of the fronts doors of the ITS building is the elevator. The is an enclosed cubic space the could fit approximately 2-3 people. The walls facing those who would stand in the were metallic, but once the elevator doors closed there be no opening for the sound to escape. The floor was not metallic, it was actually tiles that were plastic in texture.

Recording Setup. The TASCAM DR-40 sound recorder was held ~3-4 feet off of the ground with its mics (covered by a windscreen) facing the balloon ~5-6 feet away (the balloon was held in one corner of the elevator diagonally from the recorder which was in the opposite corner).

Reverberation Time.

Max Intensity: ~74.82 dB

30 dB drop: 0.21 seconds

50 dB drop: ~0.55 seconds

60 dB drop: 1.024 seconds

Minimum Intensity: ~12.98 dB @ ~2.31 seconds

Back to ambient: ~12.5 dB @ 1.34 seconds

Acoustic Description. The space’s facing walls are all metallic and enclosing not allowing for much sound to escape the elevator with only a change in texture present on the floor. As a result of the enclosing metallic walls of the elevator, there was not much reverb to be heard which is why we are provided with a clapping/popping sound of the balloon. This also visible in the spectrogram.


Acoustic Space: Edmunds Breezeway



Space Description: This balloon pop took place in the breezeway of Edmunds, between the entrances of the two different buildings of Edmunds. The left, right, top, and bottom of where I was standing was made of the same smooth concrete material, and the recording took place in the middle of the breezeway. The recording was taken around 5:00 P.M.

Recording Setup: The recorder used was the TASCAM DR-40, and it was placed about 4 feet from the ground and about 5 feet away from the balloon.

Reverberation Time:

Max Intensity: 86.14 dB

30 dB drop: 0.896 seconds

50 dB drop: 2.325 seconds

60 dB drop: the recording never drops 60 dB.

Minimum intensity: 28.342 dB after 4.32 seconds

Back to ambient levels: 32.803 dB after 2.43 seconds

Acoustic Description: The breezeway was not a very open space and resembled a tunnel, so there was quite a bit of reverberation because sound would bounce back after it hit one of the many walls that it would encounter. It is visible form the spectrogram that the echo of the pop was sustained for longer than usual, but eventually returned back to its ambient levels after a couple of seconds. The sound was able to finally escape through the entrances and the exits of the breezeway, but only after bouncing on the ceiling, ground, and walls, which were characteristic of this acoustic space.


Mead Hall Elevator




Mead Hall is located near the center of Pitzer College’s campus. Mead is build as four towers, connected by elevated walkways. The northwestern tower is named W and in clockwise order the other towers are named X, Y and Z. Mead is the oldest building on campus that houses students and the only elevator in the complex is located in Y tower. The elevator is dimly lit and smells of stale air. Above the door there are several empty bottles wedged between the light and the ceiling. The linoleum floor is chipped, the walls are imitation wood, and only decorated by a lone, empty cork board. Since the time of this recording the elevator has been refurnished with metal panelling and although it is arguably more aesthetically pleasing, it has broken several times and is frequently out of service.


Reverberation time:

30dB decay: .2 seconds

50dB decay: .5 seconds

60dB decay: .7 seconds

decay to background level: 2.9 seconds

Acoustic description:

For this recording I set up the TASCAM DR-40 recorder on the floor using the tripod for stability and held the balloon 3 feet in the air above the microphone. At 10:45am on march 31st residents of  Mead’s Y Tower heard a loud BANG (3 actually since the first two popped prematurely)!!! I expected the small, enclosed space of the elevator to reverberate the pop for longer than it did. The spectrogram shows the high frequency decayed relatively quickly, by .8 seconds, compared to the low frequencies, which took 3 seconds. I know cork is a very absorbent substance, and it may have contributed to the quick decay. I imagine the mechanical workings of the elevator contributed to a slightly elevated baseline. The intensity graph shows a series of fluctuations in intensity which take place at the end of the decay and this could have been from the elevator’s many moving mechanics, or it could be a result of the space’s reflective sound qualities.

Case Courtyard Feb. 4, 2014







80.5 dB (maximum intensity @ 3.2s)
50.6 dB (@ 3.5s)
30.7 dB (@ 4.5s)
26.5 dB (minimum intensity @ 4.7s)


This recording was taken at Case Courtyard, which is an outdoor space but surrounded by a two-story brick building in all four sides (except an opening in the North West corner). Its concrete floor (ground) and the surrounding walls probably cause any reverberant sound to bounce/rise upward. At the time of recording, there were two wooden tables out in the courtyard. There were two people in the area including myself and another person holding up the balloon.

According to the data, it took 1.5 seconds for the balloon pop to decrease from the maximum intensity, 80.5 dB, to the minimum intensity, 26.5 dB. The difference between the two extrema is 54.0 dB, which is somewhat close to 60 dB. At the time of recording, the person who was holding the balloon spoke soon after the balloon pop (within the first 10 seconds after the pop, and closer to where the minimum intensity was taken from). For this reason, I had to cut out the very end of the recording. This may have prevented us from seeing the decibel volume decrease even more.

Mead Tunnels




Reverberation time.
30 dB decay: 1.9 sec
50 dB decay: 3.6 sec
60 dB decay: 4.9 sec

This recording was done in the underground tunnels beneath X and Y towers in Mead Residence Hall at Pitzer College. It is a very small confined space, made primarily of concrete and brick. The area is completely enclosed as is easily heard from the popping of the balloon. The exact point in the tunnel that I chose to pop the balloon in was devoid of any objects except some metal piping that runs throughout the tunnels.

Atwood Dorm Bathroom Balloon Pop

Location: This recording was taken in the bathroom of one of the suites on the third floor of Atwood Dorm at Harvey Mudd College.

Description of the space: Atwood dorm is known for its gigantic bathrooms. For this recording stood in the shower, which is about 1.5 m wide and 1.5 meters long. There is a door leading into the bathroom hallway that has two sinks. Past the sinks there is a room with a door inside of which there is a toilet. Across from the toilet door is the entrance to the bathroom. The recording device was on a tripod at about chest level attached to one of the towel racks outside the shower. It was about 2 meters away from me.

Reverberation time:

Maximum intensity: 90.99 dB

30 dB drop: 61.4 dB @ 0.5 s

50 dB drop: 40.8 dB @ 1.0 s

Minimum Intensity: 40.8 dB @ 1.1s

Back to ambient: 44 dB @ 1.1 s

Acoustic Description: I expected the bathroom to have a longer reverb time but surprisingly this bathroom dampens the balloon pop sound rather quickly. One explanation for this could be that the bathroom is actually composed of porous concrete blocks (a material used in most Harvey Mudd buildings). Since this material has a lot of holes, it does not reflect sound well and thus reduces the reverb. Furthermore, I placed the recorder outside of the shower so the reverb may have been lost. The decay time was neither long nor short; it only took 1.1 s to reach its minimum intensity, which was also the region of ambient sound. The greatest source of background noise was the bathroom fan that was actually quite loud. This explains why the ambient sound level is so high. As can be seen on the spectrogram, even after the balloon pop, there are a lot of frequencies in the low to mid register.


reverb-atwood-bathroom-intensity reverb-atwood-bathroom-spectrogram reverb-atwood-bathroom-waveform[a

Pitzer Green Bowl Balloon Pop





Location: The Green Bowl, Pitzer College, Claremont, CA

Description of the space: The Green Bowl is located between East and West Dorms of Phase II at Pitzer College. The circular depression is covered in thick grass with a secant cement wall to one side.

Recording setup: The balloon was popped down in the grassy depression. The recorder was held 2 feet away from the balloon.

Reverberation time:

Max intensity: 82.81 dB

30 dB drop: 53.01 @ 0.128 seconds

50 dB drop: 32.10 dB @ 0.448 seconds

Minimum intensity: 31.7 dB @ .458 seconds

Back to ambient: ~30 dB @ .5 second

This space absorbed the sound of the popping balloon quickly as a result of the grassy enclosure and the outdoor environment. I hypothesized that the secant cement wall might result in an interesting reverberation however we did not encounter any statistically significant fluctuations in the sound decay.

Archway of Frary Dining Hall (Pomona College)



Location: Frary Dining Hall. Frary Dining hall is located on north campus of Pomona College (Claremont, CA). Because this recording was taken at approximately midnight on a Sunday (after Snack), the steps were completely empty except for 3 other students. The archway encloses the steps leading into West side entrance of Frary Dining Hall.

Description of the space: The steps leading into the West entrance of Frary Dining Hall has tremendously high ceilings making it an optimal space for a number of acapella group practices, and instrument playing. The steps descending the stairs in front of Frary Dining Hall has a mural of “Genesis” by Rico Lebrun.

Recording setup. For this recording, the microphone was placed on top of a round table while the 18” diameter balloon was popped about three feet away. The recording device was TASCAM DR-40 Linear PCM Recorder. 

Acoustic Description: The descending Frary DIning Hall steps enclosed by the archway amplifies sound at a greater capacity that a number of other locations around Pomona College’s campus. Because the space is incredibly vacant with characteristics of an open container, the sound was able to bounce and echo off of the space at a higher capacity. It took the balloon pop approximately 3.33s to decay, which can be explained by the acoustic power of these steps.

Reverberation Times:

  • Maximum Intensity:  86.21 dB
  • Minimum Intensity: 29.42 dB
  • 30dB drop after 1.26 s
  • 50dB drop after 2.61 s
  • Reached minimum intensity after 3.36 dB
  • Reached maximum intensity after 0.224 s
  • Returned to pre-pop intensity level after 3.33 s
  • Frary Steps


An Acoustic Space at El Barrio Park



A very reverberant single-stall women’s bathroom within the property of El Barrio Park, located right along side CMC. The bathroom is built from concrete and hard stone.

Recording setup: I held the recorder as a friend of mine aided me in popping the balloon.


Reverberation times and such:

89.0 dB (maximum intensity)

47.3 dB (minimum intensity)

1.423444 seconds (drop by 50db)

0.132778 seconds (to maximum db)

1.551444 seconds (to return to around 36.190841 background)

Screen Shot 2014-03-17 at 9.40.04 AM Screen Shot 2014-03-17 at 9.58.59 AM


Acoustic description

The spectrogram and wave analysis in both Pratt and Audacity aided me in understanding the sounds shape and form on a more physical level. The balloon recording is short, so there isn’t many second nor even milliseconds before the actual pop ensues. The build and the drop both seem fast. Though I had expected a lengthy reverb when I decided on location, that is not what was displayed in the recording. The pop was fast and the initial reverb was strong, but it dropped quite quickly. In the spectrogram analysis, you can see how short the time span between pre-and post pop level similarities are.


Acoustic Space: Pomona Track

Description of the Space

The event occurred in the middle of the Pomona Track. Picture a classic running track: an open grassy field surrounded by an oval track of probably a quarter mile circumference, and the land surrounding the track is slightly elevated forming a shallow bowl shape. There is also a rectangular metal equipment shed on the side of one of the straightaways of the track, probably 20 feet long.

Recording Setup Recording Device

An 18” balloon was popped and recorded using a TASCAM DR-40 sound recorder. I stood in the center of the track and popped the balloon while a pal recorded the event with the microphone about 3 feet from the balloon and pointed in its direction. The pop was recorded on Wednesday, March 5 2014 at 9:00pm.

Reverberation time

-Maximum Intensity: 86.85 dB

-Minimum Intensity: 34.91 dB

-30dB Decay: .03 s

-50dB Decay: 1.56 s

-Return to Background Level: 1.7 s

Acoustic Description

Using Pratt, the recording was edited down from just a moment before the pop to when the audio returns to its pre-pop levels. The visible sound graph that we get shows the sudden spike of the initial pop and its extremely brief decay, then a moment of near silence before we see a considerably softer but distinct echo. I’m quite sure that single echo is coming off of the equipment shed that stands on one side of the track.

Visible Sound Graph

The visible intensity contour plot gives us a similar image. There is the initial spike followed by a steep drop and then the clearly audible echo, which we can now see is just about half as loud as the initial event. The echo quickly dissipates back to the pre-pop background levels.

Visible Intensity Contour

Again the same sonic event is visualized in the spectrogram. The initial pop makes up the massive window of frequency in the beginning, which immediately drops into the much softer echo and then decay.




Scripps Parking Garage, 5th March, 8:30p.m.



Spectograph copy

Description of the Space: 

This is a rectangular basement parking garage located underneath the Scripps College field. The space itself is made up of only concrete walls and pillars that cause sounds in the space to produce a prolonged echo. The lot was about half full, however, it must be noted that there were no cars around where the balloon was popped so as to avoid any of their alarms going off. There were no background sounds. The space was pin-drop silent while this balloon pop was recorded.

Recording Setup:

I used a TASCAM DR-40 sound recorder to record this reverberant space. My friend burst the balloon while I operated the sound recorder. The recorder was located approximately 4 feet from the balloon, which was popped in the middle of the parking lot.

Reverberation Time:

30 dB decay: 1.3 seconds

50 dB decay: 2.3 seconds

60 dB decay: –

decay to background level: 2.9 seconds

Acoustic Description:

Being an underground car park, the space was surrounded by nothing but cement (the walls, ceiling, pillars, and floor!). This meant that there was bound to be a prolonged echo no matter what. The fact that the parking lot was relatively empty only increased the chances of this happening. It is because of this echo that it takes the surrounding area so long (2.9 seconds) to return to its original sound level.

Due to the fact that the balloon was popped in a relatively enclosed solid space, it reached a massive 89.135 dB as its maximum intensity. From the spectrogram above we can see that there was barely any background noises prior to the balloon pop. This graph also shows that the sound lingers before dissipating slowly.

Reverberant Spaces: Shanahan Center, HMC, 2-23 3 pm




reverb-HMC-Shanahan-courtyard-w reverb-HMC-Shanahan-courtyard-i


Description of the Space: The Shanahan Center for teaching and learning is the newest building on Harvey Mudd College’s campus, as of 2014. “The Shan” opens onto a set of wide stone ledges, leading down like stairs to the open basement level of the building. Sunk almost into a pit, the courtyard is nearly an ampitheater, and one could imagine performances on the rough tile ground. The stone along the walls is cool, smooth, and gray, and broken only by the glass wall of a lobby on the northern face. Above, open space stretches past the three stories of the building, the floors arranged so one would look up with the square walls framing the sky. From the first floor up, the walls are made of beige, plasticy tiles and windows. The courtyard is approximately 20 x 40 feet wide at the lowest level, with each ledge – along side smaller stairs – dropping down in steps about 3 feet wide and 3 feet tall.

Recording Setup: The microphone was placed at the edge of the lowest stone ledge, less than 1 foot from the edge and facing into the courtyard. The balloon was held 2.5 feet away from the microphone to combat ambient noise from outdoor sounds.

Reverberation Time:

30 db Decay: 0.36 s

50 db Decay: 0.94 s

60 db Decay: 1.36 s

Decay to background level: 1.55 s

Acoustic Description: We see in the spectrogram above that the background noise of the space is only the 400 Hz and below range. The balloon pop is clearly seen as we have more intense presence of frequencies throughout the spectrum as it is popped. In the spectrogram, we see not just the decaying of the overall sound to the background noise, but can see that the higher frequencies fall out first, while middle frequencies (up to about 1000 Hz) remain for the longest. Overall, the reverb time of 1.36 s is fairly fast. The courtyard echoes sounds, though the echo is not contained in the recording, but the length of the pop is sustained only for the brief moment. The stone walls reflect the sound back, but the steps and floor are more porous, and absorb the sound.

The longer sustained middle frequencies seen in the spectrogram may almost be taken for a muddiness in sound; what sounds that do carry are carried indistinctly. The rest of the reverberation is a general woosh of air that might almost be confused with the wind knocking down a chair or table. Still, the reflection off of the walls is audible in the recording.

It is of note that this courtyard is referred to sometimes as the “Shakespeare Plaza,” as the hope is that it will be a live performance space. Given the echoing and muddiness, it may prove to be an unwise decision, but as the space is untested for such performances as of 3/6/14, only time will tell.

Seal Court at Scripps College






Location: Seal Court is a courtyard at Scripps College. Four single story buildings enclose the courtyard. The west wall is the  Malott dining hall,  the Motley Coffee House serves as the north wall, the student mail room is the south wall, and the east wall is a career student resource building. In the center of the court is a large water feature that includes two fountains in the form of seals facing each other. I would describe the sound of the fountain as the space’s keynote. Students often sit outside in Seal Court to enjoy their meals from Malott or their coffees from the Motley. This contributes to the wide variety of soundscapes the space can offer: At some times of the day, the court is serene, with only water falling into the pond sounding. At other times, for instance around noon on a sunny day, the courtyard is typically bustling with students and faculty.

The recording included here was taken at a time of quiet and calm, at 9:30 on a Tuesday morning. At this time, many students are heading to their 9:35 a.m. classes. In the soundscape included, a very careful listening will reveal the patter of feet shuffling across the brick ground of the courtyard, and the gentle fall of the water from the Seals’ mouths. Mostly, this soundscape speaks to the tranquility of the courtyard on a sunny Tuesday morning. Recording

Device: TASCAM DR-40 recording device Recording setup: The recorder was set on the brick ledge surrounding the central water feature.

Acoustic Space: Scripps–Kimberly basement


Description of the space.
The acoustic space chosen was the basement of Kimberly—one of the dorms on Scripps campus. To get to the basement, one must go down a set of narrow concrete stairs. There is a laundry room directly in front of the staircase and the basement continues onward as a long hallway with various locked rooms for storage. The end of the basement hallway—furthest from the laundry room—was chosen as the location for the balloon pop.

Recording setup and recording device.
An 18” balloon was popped and recorded using a TASCAM DR-40 SOUND RECORDER. The recorder was held about one foot away from the balloon during recording. The microphone was pointed directly at the balloon where the puncture was made. This recording was made on Wednesday, February 19th 2014 at 8:00pm.

Reverberation time.

Maximum Intensity: 91.18 dB
Minimum Intensity: 26.52 dB
30dB drop after 1.07 s
50dB drop after 1.81 s
Reached minimum intensity after 0.43 s
Reached maximum intensity after 0.60 s
Returned to pre-pop intensity level after 3.33 s

Acoustic description.
Using Audacity, the balloon pop recording was cut when the waveform diagram appeared to return to pre-popping conditions. The Audacity waveform diagram of this recording is identical to the one generated using Praat.

Graph of sound waveform generated using Praat.

However, the Visible Intensity Contour plot demonstrates that the reverberations had not quite ceased yet.

Visible Intensity Contour plot was generated using Praat.

This is evident from the spectrogram as well.

Spectrogram generated using the Audacity.

The shading before and after the pop are not quite the same shade—meaning the recording was cut a bit short. Despite the premature cut off, the long-lasting reverb tells us that the acoustic space is likely to be narrow and made of material that readily reflects sound (rather than absorbs the sound).

Soundscape: the Motley Coffeehouse


Recording setup and recording device.
This soundscape was recorded using a TASCAM DR-40 SOUND RECORDER. This recording was taken in the Motley Coffeehouse on Wednesday, February 19th 2014 at 8:20pm. The recorder was attached to a tripod and was placed on the counter facing the espresso machine behind the bar. The microphones were opened such that the general area where baristas prepare drinks could be captured.

About the soundscape.
The Motley is located in Seal Court near Malott Commons on Scripps College campus. The building is small, and is divided into two sections: the seating area and the bar. Motley is typically crowded with students studying at tables, on couches, or sprawled out on the music stage.

Photo courtesy of the Motley website.

The bar is where the main entrance is located and where customers order food and drinks.

Photo courtesy of the Motley tumblr page.

The recording was specifically taken at the bar with the microphone pointing toward the espresso machine. This gives the listener an opportunity to experience the auditory perspective of a Motley barista. The recording captures the process of making a mocha. Sounds of a barista pulling espresso shots and mixing them with chocolate and steamed milk can be heard. Music, baristas talking, and a student placing an order can also be heard in the background. Sounds that could be described as archetypal for coffeehouses could be the background music and the sound of the various machines. A signal present in this recording would be the one customer placing an order. The softness of the girl’s voice indicates that the recording was taken at a time when the coffeeshop is not busy. Another signal is the lack of drinks being called out at regular intervals. From these signals, it is likely that the sounds were recorded during the evening hours since the motley is typically busy in early morning hours. A keynote of this recording would be the music and voices in the background because they are both constants throughout the recording where the listener does not need to actively pay attention. From the perspective of all baristas as a community, the sound of the coffee grinder and the running of water as espresso shots are pulled could be seen as soundmarks of a coffeehouse.

Reverberant Spaces: Frary Dining Hall



Location: Frary Dining Hall. Frary Dining hall is located on north campus of Pomona College (Claremont, CA). Because this recording was taken at approximately midnight on a Sunday (after Snack), the space was completely empty of people except for a worker and a friend who sat silently nearby.

Description of the space: Frary dining hall is an enclosed eating space with cathedral-like high ceilings. The floor is tiled and the seating arrangements follow no specific order. The majority of the furniture is composed of wood. There is a separate space where students are able to get food as well as dispose of their dishes. There are also two separate private dining locations within this space. For this recording, the main doors to the dining hall were closed including the doors that lead to the food area.

Recording setup. For this recording, the microphone was placed on top of a round table while the 18” diameter balloon was popped about three feet away. The recording device was TASCAM DR-40 Linear PCM Recorder. 

Reverberation Times:

  • Maximum Intensity: 92.25 dB
  • Minimum Intensity: 41.24 dB
  • 30dB drop after 0.743 s
  • 50dB drop after 2.77 s
  • Reached minimum intensity after 3.32 s
  • Reached maximum intensity after 0.05 s
  • Returned to pre-pop intensity level after  3.56 s

Frary Intensity

Frary Dining Hall Balloon Pop Spectrograph

Acoustic Space: The Oratory







Location: The Oratory in the Margaret Fowler Garden, Scripps College, Claremont, CA
Description of the space: The Oratory is located in the Scripps College Margaret Fowler Garden. It is a relatively small, circular place of worship, with a single stained glass feature. There is little furniture in the room to obscure the sound waves. There is a statue on the east wall and the door that opens to the garden is opposite, on the west end.

Recording setup: The balloon was popped in the center of the circular oratory. The TASCAM DR-40 recording device was held 3 feet away from the balloon.

Reverberation time: 3.38 seconds

Max intensity: 73.48 dB at 1.03 sec

30 dB drop: 1.71 seconds following max intensity

50 dB drop: 3.37 seconds following max intensity

Minimum intensity: 20.02 dB

Back to ambient: 20.24 dB 3.66 seconds following max intensity

Acoustic Description: The Oratory proved to be a very interesting acoustic space. As the sound decays, the reverberation sounds almost homophonic, with the archetypal reverberation sound accompanied by what sounds like a drone tone below it. This tone is the final sound to entirely diminish. This is likely due to the shape of the room and its small size. Whether there is intentionality in the acoustic design is of interest. As an Oratory, it is possible the space was designed with, at least, speech in mind, if not also vocal music.

Seaver Auditorium Foyer, Feb 15, 2014






Description of the space.  Foyer outside Seaver Auditorium, between Seaver North and Seaver South buildings, Pomona College.

Seaver Auditorium is host to many events in the natural science departments at Pomona College.  It holds large introductory science classes such as General Chemistry, Organic Chemistry, Introductory Physics, and others.  Visiting lecturers give their talks in the auditorium.  Accordingly, the foyer outside it is also full of people on a regular basis.  Whenever the large sections in the auditorium get out, the foyer is filled with students.  After an Organic Chemistry exam, students hang out in the foyer afterwards, nervously discussing what they wrote.  After a lecture from an esteemed visitor, groups of professors and students congregate in the foyer, chatting for long after the talk is over.

The foyer itself is not much to look at.  It is a utilitarian 30 ft cube with one open face pointed towards College Avenue, a major thru street (see diagram below).  It is made entirely of grey concrete, with no ornamentation except for the back wall, where the doors to the auditorium are.  This wall has vertical grooves spaced 2-3 inches apart.  I wonder if this is to help with reverberation, since the space is entirely concrete.  Four square pillars are evenly spaced in the center.  The floor is made of dull reddish brown tile. The metal double doors to the auditorium are dented from wear.

Recording setup. I popped the balloon about 5 feet in front of the doors to the auditorium.  The microphone was located about 10 feet away, sitting on a concrete bench, about 2 feet from the concrete wall (see diagram below).


Reverberation time.

30 dB decay: 0.64 sec

50 dB decay: 1.42 sec

60 dB decay: 2.35 sec

Decay to background level: 2.92 sec

Acoustic Description.  The foyer readily amplifies and echoes sound—the microphone was at least 10 feet away and still picked up a maximum decibel level of 85 dB.  This is due to all the hard surfaces present, as there is nothing but concrete walls, concrete ceiling, concrete floor, and metal doors.  The balloon pop had a relatively long decay time: it took 2.9 sec to return to the background noise level.

The foyer has significant background noise, since it readily amplifies passing cars on College Ave, which is about 50 feet from the opening.  This can be seen in the spectrogram:  there is noticeable volume in the 20 to 200 Hz range before the balloon pop.  These frequencies are intensified with the balloon pop, but after the higher frequencies associated with the balloon pop have decayed, this background noise is still present.  This suggests that the foyer is adept for echoing sounds in this lower range.

Pomona College Seaver Theater 12:35pm Tuesday Feb 11th, 2014


Description of the space:


This recording was taken at 12:35pm on Tuesday, February 11th, 2014 in the courtyard of Seaver Theater, which is located at 312 E. 4th Street, Claremont, CA. 91711 (see above satellite image by GoogleMaps).

Recording setup: The recorder (on its tripod) was set in the middle of the courtyard on the concrete ground, and all backpacks and other recording materials were moved far out of the way.  The balloon was popped approximately three feet in front of the recorder and four and a half feet above it.

Recording device: TASCAM DR-40 Sound Recorder, set to volume 33

Reverberation time:

30 dB decay: 0.209 seconds

50 dB decay: 2.554 seconds

decay to background level: 2.556 seconds (but reached minimum post-pop sound level at 4.1573 seconds)

60 dB decay: did not occur

Acoustic Description:



As we can see, the above sound images show a fairly fast initial drop in sound at the onset of the balloon pop (down 30dB), followed by a slower decrease to the minimum level of post-pop sound.  We can try to account for these characteristics by analyzing the spatial features of the vicinity of the balloon pop. Seaver Theater is normally a fairly quiet space, but because of the construction of the new art building nearby, the background noise level during this time was fairly high.  I thought that recording around 12:30 would minimize potential conflicting background noise, since students would not be walking to class at the theater and the many of the construction workers would be on lunch breaks.  Also, there are many trees and branching plants in and surrounding the courtyard, so many birds nest here (as one might hear on this recording before the balloon pop).  This fact might be able to explain why the sound level actually dropped to 26.2dB, or below the level of pre-pop background noise (which was about, on average, 32.4dB).  The birds’ reaction times to the noise would then also contribute to how fast the sound level dropped to its minimum point.

Furthermore, the courtyard of Seaver Theater is surrounded by tall, cement walls, where sound can bounce off and reverberate.  Indeed, there is even a tall, cement staircase (at the southernmost part of the courtyard in the satellite image above) that the balloon was popped from about 8 feet away.  There are only a few places where sound can escape.  The most obvious is from the top, as no ceiling exists in this courtyard.  There are also various entry and exit-ways through which sound may escape.  Thus, although the sound might have dropped fast at first (due to the initial decay out of the courtyard through the top opening and sides), bits of it were still left over, reverberating back and forth off the high walls until all the sound was finally able to “bounce” out of the courtyard and into the sky.

Wig Lounge – Balloon Pop



Wig Lounge

I was in Wig Lounge early in the morning. It was very quiet. The lounge is very peaceful; the ceiling is about normal height, maybe a bit lower. Carpeted floors, a lot of chairs, and few windows. I stood with the balloon about 3 feet from the microphone, which was sitting on the table.

Reverberation time: .0658741 seconds
30 dB decay:  0.384 seconds
50 dB decay:  1.194666 seconds
60 dB decay:  N/A
decay to background level: 1.205333 seconds
Reverb Pomona Wig Lounge GraphsReverb Pomona Wig Lounge Spectrograph

Reverberant space: Pitzer Amphitheatre






Description of the Space: I went to the amphitheatre in between Pitzer’s freshman and sophomore dorms. This area is outdoors, with large buildings relatively nearby to the north and south, Claremont boulevard is to the east, and another dorm is much farther away to the west. Immediately, the balloon was surrounded on all sides by amphitheatre seating.

Max Intensity: 80.97 dB

time to drop 30 dB: 2.75 sec

did not drop 50 or 60 dB

2.75 seconds to return to pre-pop level.

Balloon pop at Bridges Hall of Music (“Little Bridges”, Pomona College, Claremont Ca.



Little Bridges Balloon Pop

Location. 150 E. 4th Street, Claremont, CA 91711
Concert Information: 909-607-2671

Recording setup. Hold 17″ Diameter Balloon 3 feet above the stage floor, 10 feet from the front edge of stage. Recorder set 6 center 6 rows from stage center

Recording Device used. ZOOM H2N Record settings: Central Mic – ON

Reverberation Times. Drop to 30dB .89 seconds, Drop to 50dB 2.14 seconds, Drop to 60dB Did not drop to 60dB, Seconds to reach minimum 1.54 seconds, Seconds to return to Pre Pop 2.3 seconds

Audacity Acoustic description. The Spectrogram reveals frequencies peaking a 7000 Hz and decreases over 1.5 seconds to 1000 Hz.

Overall, the spectrogram shows the a long duration of reverberation over the whole audible hearing range,

Soundscape: Platt Campus Center, HMC



The soundscape is of the main room of the Platt Campus Center on Harvey Mudd.  This room is very large, 100ft x 100ft at least, and has high plaster ceilings (~30 feet high) and wooden flooring.  The room is furnished with a few dozen couches, tables, and rolling whiteboards, and has wooden and glass walls.
This space serves as a “living room” for many students at Mudd; they hang out on the couches, work on the whiteboards, and use the coffee machine to support their caffeine addictions.  Tutoring hours for most classes are held in Platt, and team or group meetings often happen here.  Additionally, college-sponsored fun events are usually held in Platt  Due to this, the students have a sort of love-hate relationship with the space; it represents hours spent doing work, but also can be the setting for group bonding and fond memories.
Audible in this recording are the sonic archetypes of an academic building where students work together: footsteps on the hard wooden flooring and the ever-present murmur of students checking answers or asking each other questions.  The “ka-chunk” of the door next to the mailroom and the beeping and hissing of the coffee machines are soundmarks very distinct to Platt.   Also in this recording, we can hear the students playing and singing along to music as they work, which could be a keynote, because students sing along to music enough that it isn’t too remarkable.

Reverberant Space: Jacobs Science Building Stairwell, HMC



Location: This recording was taken in a 4-story stairwell in the Jacobs Science Building on Harvey Mudd Campus.

Description of the Space: I took the balloon pop recording on the 1st floor landing in the stairwell between Jacobs and Keck on Harvey Mudd Campus.  This is a stairwell that spans 4 stories; the stairs themselves are concrete, the doors are heavy and wooden, and the walls are plastered.  The stairwell is open in the sense that one can stand at the very bottom and look up the center and see all the way up.  For this recording, I closed all the doors so the stairwell was isolated, placed the recorder 3 steps up from the 1st floor landing, and popped the balloon on the 1st floor landing (this means the recorder was about 6 feet from the balloon).

Reverberation Times:
Maximum intensity: 74.4 dB
30 dB drop: 2.5 s after peak
50 dB drop: 2.8 s after peak
Minimum intensity: 18.1 dB
The space apparently reverberates at 200, 500, 1000 Hz.




Acoustic Space: Garrison Theater Stage



reverb-scripps-garrison-S&I PNGreverb-scripps-garrison-spectrogram PNGreverb-scripps-garrison-diagram

Location. Garrison Theater on the Scripps Campus at 10th St. and Dartmouth Ave. in Claremont, Ca. 91711

Description of the space. This newly renovated Theater has had many new changes to the interior and exterior of the building.

Recording setup. Hold 17″ Diameter Balloon 3 feet above the stage floor, 10 feet from the front edge of stage. Set Recorder vertically (with insulation) on front edge of stage 10 feet from balloon.

Recording Device used. Olympus DM-620   Record settings: Central Mic – ON  (3 Mics operational) !!,  Sensitivity – LOW,  Mode – WAV 44100 bps 16 bit,  Level – Manual,  Zoom – OFF,  Low Cut – OFF,  Volume Level – 8  (1-16 max)

Praat Findings. Balloon Pop Maximum intensity level   92.67dB,  Minimum intensity level  42.07dB

Reverberation Times.  Drop to 30dB   .89 seconds,  Drop to 50dB  2.14 seconds,  Drop to 60dB  Did not drop to 60dB,  Seconds to reach minimum  1.54 seconds,  Seconds to return to Pre Pop  2.3 seconds

Audacity Acoustic description. The Spectrogram reveals frequencies peaking a 3000 Hz and lasting for almost 2 seconds. It was also strong between 100 and 600Hz range. Background frequencies were 600Hz and below.

Overall, the spectrogram shows the Balloon explosion was absorbed and dampened very quickly over the Audible Hearing Range, which would be the acoustic goal of a well designed Theater.

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.

Reverberant Spaces: Patio at Larkin Park



Location: This recording was taken on the patio of the building at Larkin Park at Cambridge and Harrison.

Description of the Space:On the North side of the intersection of Cambridge Ave. and Harrison Ave. is a small park. There is a building with a south facing glass wall with a patio and shelter in front of it. The recording was take near the center of the concrete patio that extends the length of the building (~100ft), protruding about 5ft. The wall facing the patio is almost completely made out of glass with some brick, and faces an enclosed rectangular field and parking lot. The recording was taken around 8am.

Recording Setup: The microphone was raised about 4ft from the ground, and the the balloon was popped about 5ft away, using a Tascam DR-40.

Reverberation time

Max intensity: 81.47 dB

30 dB drop: 0.18 seconds

50 dB drop: 0.59 seconds

Minimum intensity: 21.12 dB @ 2.0 seconds

Back to ambient: ~21 dB @ 2.0 seconds

Acoustic Description: The space’s only facing walls are the cement ground and wooden ceiling, not giving the sound much to reverberate off of. But, because of the hard surfaces, a slapping echo is heard once (it is also visible in the spectrograph). The grassy field that the space faces is surrounded by stone walls, which would make sense as having been what caused the echo.



Acoustic Space: Blaisdell Bathroom






Location. Restroom B12, on the second floor of Blaisdell Residence Hall at Pomona College.

Description of the space. This bathroom is a medium-sized, rectangular room with tile floors and three drywall walls. The fourth side of the room has a shower curtain drawn across it, with a bit of space above the curtain. The side opposite that has protruding sinks and mirrored cabinets. In the corner of the room is a walled-off area for the toilet. Thus, the rectangular shape of the room is broken up by protruding objects on various walls.

Recording setup. The microphone and balloon were six feet apart from each other. The microphone stood between the two sinks on the countertop, close to the wall. The balloon was popped from a height of almost six feet, at a spot close to both the shower curtain and the walled-off toilet area. Though near two “walls” of sorts, this location was near the center of the room.

Reverberation time.
maximum intensity: 80.13 dB
minimum intensity: 34.77 dB
30 dB decay:  0.62 sec
40 dB decay:  0.92 sec
decay to minimum: 4.02 sec
decay to pre-pop background level of 41.34 dB: 0.82 sec

Acoustic description. Because the space is fairly contained, with many hard walls and surfaces for sound waves to bounce off of, the sound does reverberate pretty strongly. However, there are avenues for sound to escape, as well; the curtained wall especially, along with the spaces under the door and under the walled-off area for the toilet, allow the sound to dissipate and prevent the humming noise after the balloon pop from approaching one specific frequency too closely.

Acoustic Space: Case Courtyard 6:30 PM







Location: Case Dorm courtyard, Harvey Mudd College, Claremont, CA

Description of the space: The courtyard is a lowered area in the center of the building that forms the dorm. The dorm building is two stories tall and forms a shape resembling the letter C. The building material seems to be some sort of pink brick. The courtyard has two main levels, with some wooden tables on each of the levels. The upper level is at the same level as the base of the building. The second level is 6 steps below the level of building.

Recording setup: The balloon was popped 5 feet above the lower level of the courtyard. The recorder was placed on a table 3 feet away from the balloon.

Reverberation time:

Max intensity: 75.25 dB

30 dB drop: 45.25 dB @ 0.2 seconds

50 dB drop: 25.27 dB @ 0.75 seconds

Minimum intensity: 20.10 dB @ 2.3 seconds

Back to ambient: 24 dB @ 1 second

Acoustic Description: There does not seem to be any interesting acoustic qualities in this space. I think the main reason for this is due to there being no roof overhead. The courtyard is surrounded by walls except for one pathway that leads into the courtyard. If there was a roof, a lot of the sound would be reflected around the courtyard multiple times before dying down in intensity or escaping through the pathway.

Acoustic Space: Thatcher Stairwell


Location. Stairwell leading from first-floor lobby to basement of Thatcher Music Building, Pomona College, Claremont, CA.

Description of the space. It is an enclosed two-flight staircase.  The walls, which include a wall separating the two flights of stairs, are of painted concrete.  The steps and landing are covered in laminate tile and appear to be concrete underneath.  The stairwell has doorways at top and bottom, usually open, for entry and exit.  They were open during this recording.  The ceiling is at an angle, so that the distance above any step is approximately approximately ?? feet.  Total height of the stairwell from the bottom landing to the ceiling above the top landing is approximately ?? feet.

Recording setup. The microphone and the balloon were both placed near the floor of the landing between the two flights of stairs, about three feet apart.

Reverberation time.
30 dB decay:  1.8 sec
60 dB decay:  4.8 sec
decay to background level: 5.0 sec
minimum: 6.4 sec
(Using intensity graph function in Praat,)

Acoustic description.  The resonance in this space prominently reinforces a pitch that I hear as 312 Hz. In the recording this pitch (E-flat 3, just above middle C) becomes audible as a hum less than a half-second after the pop, and it remains perhaps the most prominent feature of the sound for about two seconds.