Orienting an Outdoor Amphitheater Surrounded by Natural Rock Formations

Joseph Morris – jmorris@resolutgroup.com
Instagram: @resolutgroup

Resolut Group
181 E 5600 S, Suite 200
Murray, UT, 84123

Popular version of 2pAAa6 – Measurement-informed orientation of an amphitheater surrounded by natural rock formations using in-situ impulse response analysis.
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

A venue’s beauty may draw guests in, but the acoustic experience is what brings them back.

When attending a symphony, the first desired experience is to hear and appreciate music. Musical quality is important for design aspects of an outdoor amphitheater, especially when the design is impacted by large, natural rock formations. Maxwell Park in Hilldale, UT contains several striking, extraordinary features that naturally catch any eye. Although there’s beauty in this scenery, acoustic tests were needed to help enhance the listening experience, i.e., find the best stage direction. Because of these colossal rocks, the way the stage faces can strongly change what the audience hears.

During predesign, two realistic stage orientations were compared: a stage on the north side facing south (Figures 1-3), and a stage on the east side facing west (Figures 4-6). The orientation matters because rocks are reflective and if reflections arrive at the audience at different times and from different directions, they can smear the sound and make music feel less clear. To find the best option, four types of tests were performed at each orientation: an impulse response test (to see when echoes arrive), a “chirp” test (to check how different pitches carry and whether they interfere), a real-time analysis (to see how evenly sound spreads across the audience area), and a music listening test (to hear the real-world result). The client team, including several city officials and the architect, was on-site during testing and though graphs, tables, and data analyses are useful, hearing the difference in-person made the greatest impression.

Aerial view of an outdoor event layout with a marked stage area and audience zone in a desert-like terrain.

Figure 1: Northern Stage Design

Sound level meter mounted on a tripod in a desert clearing with towering red rock cliffs and sparse vegetation under a clear blue sky.

Figure 2: Northern Stage Simulation

Tripod with mounted sound level meter standing on a wide, dry dirt field surrounded by distant rocky hills under a clear blue sky.

Figure 3: Southern Audience Area

Aerial view of an outdoor stage and audience area marked in red near sparse vegetation.

Figure 4: Eastern Stage Design

Tripod-mounted microphone setup on a dirt path with desert shrubs and red rock cliffs in the background under a clear sky.

Figure 5: Eastern Stage Simulation

Wide view of a dirt plain with green shrubs and rugged rocky mountains under a clear blue sky.

Figure 6: Western Audience Area

From the north side, sound struck the nearby eastern rock face almost immediately and provided positive reinforcement for the direct sound. However, the sound reflecting off the western rock face arrived at a significant delay causing negative reinforcement which distorted the overall quality. Those repeated reflections, arriving at slightly different times, blurred the sound, made it harder to tell where the music was originating, and confused listeners. During the music listening test, the clients were so distracted that some initially assumed the sound equipment was the problem, calling it, “low quality”.

On the east side, the audience heard stronger direct sound, with only mild reflections from farther rock formations. Those reflections helped the sound feel full and supportive. During the music listening test, listeners described their experience as clear, impactful, more evenly heard across the area, and emotional to the music that was played. The same equipment and music were used for both orientations, but the natural rock formations from the eastern side had the greatest acoustic impact.

Measurements, figures, and charts help explain why one option performs better, but the shared, real-time listening experience made the difference. Based on that direct experience (supported by test results), the east-side stage orientation was the clear recommendation to, and accepted by, the client.

Why Do Polymer Oboe Reeds Feel Different?

Fumihiko Kurosawa – kurosawa.fumihiko.24@aclab.esys.tsukuba.ac.jp

University of Tsukuba, Graduate School of Science and Technology
Tsukuba, Ibaraki, 305-8577, Japan

Naoto Wakatsuki – Institute of System and Information Engineering, University of Tsukuba
Tadashi Ebihara – Information Engineering, Tsukuba Institute for Advanced Research, University of Tsukuba

Popular version of 2pMU5 – Evaluation of Polymer Oboe Reed Vibration Using Stroboscopic Analysis under Artificial Blowing
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/page.php?page=IntHtml&project=ASASPRING2026&id=4069946

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

What if anyone who dreamed of playing the oboe could pick up the instrument and shape the sound as easily as a professional musician?

For many players, one of the biggest challenges is not the instrument itself, but the reed. This small piece of material opens and closes hundreds of times per second as the player blows, producing the sound of the instrument. Its motion can change greatly depending on the material, humidity, shape, and contact with the player’s lips. These changes often frustrate players, because even small differences in the reed can strongly affect how easily the instrument responds and how stable the sound feels.

A Small Reed with a Big Role
In recent years, artificial reeds made from polymer materials have become increasingly popular for double-reed instruments such as the oboe and bassoon. Compared with traditional cane reeds, which are made from natural plant material, polymer reeds are more durable and less sensitive to humidity. They may offer more stable playing conditions and may also help musicians who have allergies to cane. Despite these advantages, many players feel that polymer reeds and cane reeds do not respond or sound exactly the same. However, the physical motion behind this difference is not yet fully understood.

Watching Reeds Move in Slow Motion
In this study, we observed the vibration of several types of polymer oboe reeds and compared them with a traditional cane reed. The reeds were tested using an artificial blowing system, which allowed us to blow air through the reed under controlled conditions. To see the fast reed motion, we used a stroboscope, a flashing light that can make rapid periodic motion appear slow. By synchronizing the strobe light with the vibration of the reed, we could observe the opening and closing motion as if it were in slow motion. This allowed us to examine how the reed opened during each vibration cycle, as shown in Figure 1.

Figure 1. Comparison of polymer and cane reeds using stroboscopic imaging. Differences in reed motion are visible during the opening phase.

To make the experiment closer to real playing conditions, we tested the reeds in two ways. First, we allowed the reed to vibrate freely. Second, we placed a small constraint near the reed tip to imitate the way a player’s lips touch the reed. This comparison helped us examine how lip contact changes the reed motion.

What Changed Between Polymer and Cane Reeds?
The results showed clear differences between polymer and cane reeds when producing the note C5. When we added the lip-like constraint, the pitch and the opening width changed, but the basic opening and closing pattern remained similar. One particularly interesting result appears in Figure 2. The polymer reed showed three distinct peaks during the opening phase, while the cane reed showed only two. This difference suggests that the material of the reed may affect faster parts of the vibration. In other words, polymer and cane reeds may transmit high-frequency motion differently when they interact with the instrument.

Graphs showing pixel position variations over periods for polymer and natural reeds with raw and smoothed data lines in red and blue.

Figure 2. Comparison of waveforms and frequency spectra for polymer and cane reeds. The polymer reed shows three peaks during the opening phase, while the cane reed shows two.

By directly observing reed vibration, this study shows that polymer and cane reeds can move in different ways even when they are used under similar blowing conditions. These findings may help explain why players feel a difference between reed materials. They may also guide the future design of more reliable polymer reeds, bringing players one step closer to an instrument that responds the way they expect.

Creating an Affordable and Sustainable Marimba #ASA190

Honduran rosewood, which makes up the bars of most marimbas, is rare and expensive.

PHILADELPHIA, May 14, 2026 — The pleasant, earthy sound of a marimba is a key component in the modern orchestra, but their high prices, ranging from $1,000 to over $25,000, sometimes make them cost-prohibitive for schools and students.

“To me, the marimba’s beauty lies in its place as the most expressive of all the mallet instruments,” said Amartya Bhattacharya, a student at Northeastern University. “Its high ranges have the articulation and pointed sound of the xylophone, while the low ends of the instruments reach beautiful, deep bass tones unrivaled by any other mallet percussion instruments.”

Bhattacharya grew up surrounded by music, and because he loves the marimba, he was motivated to find ways to make the instrument more accessible to all so more could have the same opportunity. The keys of marimbas are primarily made from Honduran rosewood — a rare and expensive type of wood — and Bhattacharya wondered if there was a cost-effective substitute that could do the trick.

Bhattacharya will present his analysis of alternative marimba materials Thursday, May 14, at 10:40 a.m. ET as part of the 190th Meeting of the Acoustical Society of America, running May 11-15.

Person touching a wooden marimba with metal resonator tubes visible beneath the bars.

The bars of the marimba are traditionally made from Honduran rosewood, a rare and expensive resource. Credit: Amartya Bhattacharya

He began by identifying materials, both wooden and polymer-based, that could serve as replacements for the marimba bars. Then, for each material Bhattacharya analyzed the density, which corresponds to durability; the loss factor, which determines resonance; and Young’s modulus, which impacts the pitch and feel of the bars — all of which come together to determine the sound of the material.

After testing these parameters, he found that hickory wood was the best alternative from an acoustical standpoint. It also has the added bonus of being significantly less expensive than rosewood.

“The Young’s modulus value of hickory means it will respond similarly to rosewood when struck,” Bhattacharya said. “The Young’s modulus-to-density ratio also means that a hickory and rosewood bar of the same pitch will be close in size, which is important to ensure that practice done on non-rosewood marimbas will transfer to the real thing for big performances.”

There were some materials that met parts of the criteria to be used in the marimba but failed in other parts. For example, spruce wood had a similar Young’s modulus-to-density ratio when compared to rosewood, but its higher damping values meant that the musical technique of rolling — when the marimba bar is repeatedly struck to create a continuous sound — wouldn’t sound very good.

“I wanted my initial analysis of the materials to be quantitative and of their physical properties, but I hope to one day make full-sized marimba bars from the most promising materials,” Bhattacharya said.

He also plans to test more types of wood, like bamboo, and modify the hickory bars using heat and pressure to increase their density.

“The marimba is the pinnacle of pitched percussion, which is why I chose to study it,” Bhattacharya said. “Overall, I hope to find affordable options for marimba bars with enough durability to not need frequent replacement.”

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For more information:
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Main Meeting Website: https://acousticalsociety.org/philadelphia/
Technical Program: https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
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ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

More Press Releases

Listening to Liberty: How Modal Analysis Sheds Light on the Sound of the Liberty Bell

Sean Collier – smc604@psu.edu

The Pennsylvania State University Applied Research Lab, University Park, PENNSYLVANIA, 16804, United States

Jonathan Young
Aaron Stearns

Popular version of 4aMU5 – Modal Analysis of a Liberty Bell Replica
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

More often than not, what crosses your mind when hearing “Liberty Bell” is not the chime or musicality of the bell; rather, it is likely the infamous crack through its left-hand side. On this 250th anniversary, it is worthwhile to pause in its silence, and consider how it might have sounded when newly cast in 1751.

Predicting the sound of a bell feels, at first pass, relatively straightforward. The bell has a simple geometry, which is important for understanding how its vibration patterns radiate sound to your ears. The bell is made of bronze, which is essential for predicting the exact pitches at which the bell will sound, as well as how long it rings. These parameters, considered together, define this action of vibrations along the surface pushing air into oscillation, leading to the radiation of sound and the bell’s characteristic chime. The physics are well understood, but the Liberty Bell, in particular, is not. That is, surprisingly little exists in the way of geometry and material composition for the bell, which makes it a particularly challenging example.

Large bell mounted on a sturdy black metal frame inside a building.Figure 1. Photo of the Liberty Bell replica at Penn State Behrend

Simply using the meager information available online produces, frankly, a terrible sounding bell that in presence does not match the silhouette of the iconic bell. Rather than toy with parameters until things seemed “right,” we sought out a replica to measure its geometry and vibroacoustic response, so to calibrate our prediction. Modal Analysis, the act of exciting a structure to understand its vibration patterns – called modes – as well as its frequencies at which the modes vibrate, is a common tool used to isolate this information in a meaning and practical way. Some results from this modal analysis are compared in Figure 2, showing the measured vibration patterns for the replica to classical results from Rossing and Perrin [1].

3D visualizations of a bell showing vibration modes labeled hum, fundamental, and tierce with corresponding 2D outline diagrams below each.Figure 2. Comparison of the first few vibration patterns between the replica and theory

Knowing the modes and frequencies was only half the effort, though, as we noted that the geometry defines so much of the sound that we eventually perceive. Indeed, small changes to the geometry could alter the prediction considerably. To have the model be as close to truth as possible, a 3D scan of the replica was done to produce a geometry – making it likely the most accurately modeled cast bell to ever exist! Once the geometry, frequencies, and modes are in place, the prediction could be tuned so to back out the bell’s material properties – “Bell Bronze”, intrinsic to the distinct ring of bells.

Large bronze bell with wooden yoke and metal supports, shown from multiple angles including detailed 3D renderings.Figure 3. 3-dimensional scan of the replica to define the cross-section and model geometry

Through modal analysis of this replica, we were able to tune a predictive model of the bell to match the measured vibroacoustic response. Beyond the pretty shapes, the analysis tells us how pitches in the chime relate in strength and in time, illuminating the evolution of the sound over time and adding scientific context to something so often overlooked in the story of the Liberty Bell.

References:

[1] Rossing, Thomas D., and Robert Perrin. “Vibrations of bells.” Applied Acoustics 20.1 (1987): 41-70

The Sound of Coffee Tells the Tale of its Molecular Structure

Jill Linz – jlinz@skidmore.edu

Skidmore College, 815 N Broadway, Saratoga Springs, NY, 12866, United States

Additional Authors
Emily Gross
Oliver Goldman
Owen Young

Popular version of 2pMU1 – Molecular Sounds
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/index.php?page=IntHtml&project=ASASPRING2026&id=4069932

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

What does coffee sound like? The molecules that make up your morning cup of coffee was one of several molecules explored using a promising new sonification method for creating musical tones from molecular absorption spectra. Sonification is the process of converting scientific data to audible frequencies, which can then be turned into sound through standard audio programs. By relating the physical characteristics of the molecules to the characteristics of sound we were able to create a mapping scale that retains all the molecular information within a single grain of sound. This grain of sound was then used as the building block for the sound of coffee.

A grain is a bit of sound that exists for less time than the human ear can detect yet contains within it all the information known about the molecule. Once produced, even smaller samples of the grain were taken and used to create musically harmonic tones. The methods used to create these grains used standard methods found in quantum mechanics and in music synthesis techniques.

Graph showing a sharp spike and dip in a waveform centered around 0.002770 seconds on the horizontal axis.Figure 1. A 50 ms sound grain produced from data obtained by analyzing a coffee sample.
Line graph showing relative amplitude of dry coffee FTIR raw data across wavelengths from 0 to 16000 nm, with multiple peaks and valleys.Figure 2a) Raw data showing the absorption spectrum of coffee.
Blue amplitude spectrum graph showing multiple peaks between 0 and 1500 Hz with highest peak near 400 Hz.Figure 2b) The frequency spectrum produced by the coffee sound grain shown in Fig 1. Mirror image of the spectrum is shown for comparison.

Scientists use the absorption spectrum to learn about a molecule’s atomic make-up. The shape of the peaks and curves are unique to each molecule. The peaks reveal what elements make up that molecule. Fig 2a is the absorption spectrum for a drop of coffee. Fig 2b shows a mirror image view of the frequency spectrum produced by the sound grain. The spectrum produced by our methods in Fig 2b compared to the spectrum produced by the raw data in Fig 2a validated the methods used to create the sound grain.

To create the grains, a gaussian fit method was used to determine the corresponding frequencies. These were then translated into sound using granular synthesis techniques. Granular synthesis has its origins in the Heisenberg Uncertainty Principle. Sound can exist in short bits, sometimes referred to as a quantum bit in quantum computing, or a grain in granular synthesis. These “bits” are unique waveforms in which all data is contained in a time interval of less than 60 ms, as seen in Fig 1. In granular synthesis, we were interested in stringing multiple bits very closely together to build up an interesting tone. Each tone was created by experimenting with the sample size of the sound grain and then stringing multiple wave packets together to form the sound.

Comparison of small, medium, and large sample sizes showing their respective waveforms and frequency spectrums side by side.Figure 3. Comparison of sample sizes used to produce the Sound of Coffee together with the resultant sound wave and frequency spectrum for small, medium and large samples.

The Sound of Coffee can be heard in the audio sample. The three tones produced follow in the order shown in Fig 3. Playing from top to bottom, small, medium and large samples are heard. While all three samples produced harmonic qualities, the frequency spectra show that the smaller the sample size became, the more harmonic the tone became.

Audio1. The sound of coffee for small, medium and large grain samples.

Our results produced a harmonic quality in coffee, as well as in other molecules, that was absent in the atom tones produced in the author’s previous work. In addition, we also noticed that the peaks were shifted slightly as we reduced the sample size. This result aligns with current research in physical chemistry. Our next step is to investigate Iodine, as it is a purer molecular form. These results may provide us more insight to the chemical makeup of molecules and how they are understood through their unique, musical sounds.

Music Features Prominently in Global Prehistoric Archaeology and Ancient Legends

Steven Waller – wallersj@yahoo.com

Rock Art Acoustics, Lemon Grove, CA, 91945, United States

Popular version of 2aMU6 – Musical Instruments Feature Prominently in Prehistoric Archaeology and Legends of Multiple Cultures
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Put yourself in the place of one of your early Stone Age human ancestors. As you are devouring a bird, you see a hollow bone that the wind could blow through, so you breathe into it. Imagine your surprise when the bone comes alive with the piercing sound of a shrill whistle, and then your further astonishment when an invisible spirit responds from a cave on the other side of the canyon with the exact same whistling.

Early peoples did not understand the wave nature of sound. The complex acoustic principles that cause sound production from musical instruments were totally inexplicable; that goes double for sound repetition in the form of echoes. Examples will be given of ancient myths from cultures around the world describing magic flutes and echo spirits. These attempts to explain mysterious sounds by attributing them to supernatural entities underscore the misperception of such sounds in the past as otherworldly.

Sound producing objects – including flutes, drums, and musical bows – are often depicted in prehistoric paintings and engravings, which are typically situated in acoustically reflective environments such as caves, canyons, and cliff faces. Evidence is accumulating to support the theory that such rock art was motivated by the echoes and reverberation heard in those special acoustic environments. Results of archaeoacoustic studies will be presented relating musical instruments to the content and context of prehistoric art.

Another example of misperception of musical sounds in the distant past pertains to Stonehenge and other megalithic stone circles known by the collective term “Pipers’ Stones”, from an ancient legend of two magical pipers. Experimental data show that sound wave interference patterns from two flutes or bagpipes can cause the auditory illusion of acoustic shadows that seem to be cast from a ring of massive rocks blocking the sound, when in actuality it is merely sound wave cancellation from the two sound sources.

These examples of musical instruments featuring prominently in prehistoric archaeology and in legends of multiple cultures emphasize the importance of considering how the human mind has perceived and interpreted sounds over time, especially when studying archaeological sites.

“The Cave Spoke Back” ebook, a collection of archaeoacoustic publications by Steven J. Waller, can be accessed at https://www.dropbox.com/scl/fo/zx0sc652ybovt6ijf5nl0/AC2bHC3yQbTvF8lhWj5yhSc?rlkey=6je6s4zmgc9ygqme599q4c40x&st=62vrgw3f&dl=0