I'm John Torek. And I'm Danny Sullivan. And you're listening to Speaking of Design, bringing you the stories of the engineers and architects who are transforming the world one project at a time. From cars passing by on an eight lane interstate to the harmony of an orchestral performance to the serenity of nature. Sound is a huge part of the natural and built world. Today, we'll meet a team of acousticians whose mission is enhancing the sounds you want and mitigating the ones you don't.
I was not the greatest student in college. At some point, the university asked me to reconsider my path in life, and I I wound up going to a different school. That's Tim Casey. Today, he's more than thirty years into a successful career in acoustics at HDR. After finding his academic footing and earning a degree in biological sciences, Tim began his career and later enrolled in graduate level environmental engineering courses.
About the time that I had maxed out the number of classes that I could take without formally enrolling into it, I had a chance to join a local band. And so I joined the band and never finished graduate school. But his career had taken off, beginning when a transportation project manager in HDR Chicago office was looking to hire. He went to the office manager and said, I need help. You know, have you gotten any resumes lately? And Mike said,
oh, yeah. I got one right here. And he reached into his garbage can and pulled out my resume. The team was working on the environmental impact statement for a new tollway, and they had a project for Tim. To help keep me busy, the people working on the EIS asked me if I could learn how to use a sound level meter, and I wound up going out and doing traffic noise measurements, kinda complaint
based traffic noise measurements. An EIS outlines the impact a proposed project will have on the surrounding environment, including changes in noise levels. They handed Tim the manual and asked if he could see himself performing the noise modeling to predict sound levels for their report. Soon, Tim found himself playing with an entirely different set of instruments. First, we had an analog sound level meter, and that was the first tool I used.
And the FORTRAN traffic noise model, FHWA's original traffic noise model was called Stamina. Fast forward three decades, and Tim has become an industry expert who uses the most sophisticated sound level meters and noise modeling software available. As the firm's acoustic program manager, he's based in Minneapolis and oversees a team of nine across six offices. Everyone except me either has a bachelor's or a master's degree in acoustics or in a branch of engineering with an emphasis on acoustics.
As the group has grown, they've taken on specialized areas of expertise. In the broadest sense, HDR's acoustics program can kind of be subdivided into three different buckets. There's the architectural acoustics bucket, there's the traffic noise bucket, and there's the everything else bucket. These days, Tim finds himself in the everything else bucket, which can include environmental noise monitoring for wind farms, combustion turbines, hydroelectric dams, and industrial facilities.
The work has taken Tim to some interesting locations, including a boxing ring. I did a noise analysis for a proposed landfill in the Southern half of Puerto Rico and had to go there and and testify through an interpreter in a public hearing that was held in an outdoor boxing arena. I was assigned to do fairly screening level air quality analysis and noise analysis to evaluate noise from the vehicles coming and going from the site
collection vehicles, bringing trash to the site. There were public meetings, and noise was one of the issues of concern for the stakeholders. And the lawyers for the opposition asked that the person who did the air and the noise analysis be present at the hearing. Outside of work, Tim fronts his own band, Tim KC and the Martyrs, which has helped his career, but not in the way
that you'd think. When I first started fronting my own band and and performing songs, I would feel so much anxiety that I my shirt would be soaking wet by the end of a forty five minute performance out of pure anxiety. My shirts were literally dripping wet. And over time, my shirts became drier and drier. And right around that time, I started having to do expert witness testimony on wind turbine projects, and that was exceptionally stressful.
But having the experience of being completely vulnerable on stage writing something as intensely personal as a song allowed me to sit in the witness stand and withstand every attempt to, you know, try to make me trip over my words or try to intimidate me. Tim's resume even includes a project that involves travel to space.
It was at a regional airport outside of Denver, and whoever owned that regional airport teamed up with one of the few rocket manufacturer, Hopefuls, interested in developing commercial space travel. The operational plan was to take somebody up into outer space and bring them right back down. So it was it was kind of
an adventure ride. His team wrote the rocket launch noise model for the proposed spaceport, which Tim notes was the first three d GIS rocket launch noise model approved by the Federal Aviation Administration. Another project involved traveling to Point Thompson on the Northern Coast Of Alaska. There, an energy client was seeking permission to build directional drilling platforms to extract liquid natural gas and crude oil from an enormous reserve beneath the Beaufort Sea.
As part of the EIS for the state of Alaska, Tim and his team ventured north to conduct a noise analysis on the potential impact on fish and wildlife. The first thing we did on that project was to go up there and take Arctic winter survival training because the the initial plan was we're gonna look at maps and select preliminary noise measurement locations, and then we're gonna fly out to those locations with a helicopter.
But inherent in that plan was the the idea that weather changes really quickly out there. So the helicopter is gonna be able to fly you somewhere, but it may not be able to take off. So we're gonna give you this bag, and this bag has an Arctic survival suit, a tent, and an Arctic rated sleeping bag. We'll give you a deck of cards and a couple candy bars too.
And, hopefully, we can come back and get you in the morning, but you might have to spend a night in a tent in polar bear habitat during polar bears' ending season. The polar bear concern was not purely hypothetical. And as funny as that sounds, one of the weekends I was up there in the wintertime, they let me go down to Anchorage for a weekend.
And that weekend, a bear wandered into dead horse and grabbed one of the musk oxens from the herd of musk oxen that walks around in dead horse and spent the weekend eating it behind one of the buildings. So the the whole polar bear thing was a very tangible safety concern. They quickly realized the helicopters would be impractical to deploy their huge noise monitoring stations.
So then the next day, they loaded us into a school bus, and they drove us 40 miles over a road that was literally made out of ice cubes over the frozen tundra out to the drilling platform. So we did deploy the four custom made noise monitoring systems, these big four by four by four aluminum cubes with two foot by four foot solar panels on them. We loaded them up onto two snow cats and drove them off of the temporary drilling platform out into the vast
winter Arctic soundscape with the North Slope. With one of the monitoring systems deployed in a precarious position. We drove straight north off the coast of Alaska over the frozen Beaufort Sea onto a sandbar, And it really was just a it was just a stand a sandbar that protruded just a little bit above the snow and the ice. And we were on that sandbar because the sandbar next to us was taller, and it was tall enough that snow could could accumulate on the downwind side of it,
and that was polar bear habitat. We were in polar bear denning habitat during polar bear season. The team recorded for more than twenty five days, then returned home to Minneapolis to analyze the data. Gina Jarda, at the time a junior member of Tim's team, began listening to hours and hours of Arctic recordings. Well, it's creepy. So it's totally creepy. There was a month of my life as a young person that I listened to audio from the North Slope Of Alaska every day.
I was the youngest person in group at the time and so some days, I listened to what felt like nothing and I had to continue to check my audio. Like, is it still on? Because there was nothing. Then one day, I I wanna say it was, like, 06:00 at night in Minnesota at at that time of year. It was dark, and I just hear a crackle in my ear. And I'm like, that is so strange. And then the clip ended because we did randomized sampling. So we didn't listen to everything. You'd listen
to random samples. So I searched for an hour because I was like, I need to know what this crackle is. And I went back. I found it. And the reason it feels so chilling is because it's a a polar bear physically chewing on the microphone windscreen. He's chewing on the screen is what you're hearing, and that's why it feels so up close. And eve and e and even creepier listening to it over headphones in a almost deserted office at night That was how that was discovered. It's probably
one of my favorite audio clips. Gina's work in the field has taken her to both the northern and southernmost points in The United States and as far away as Djibouti. I just had the most amazing adventures out in the field. In California, I got to do a wind project, that took me on to BLM lands, and we got to hike with backpacks for miles in order to place sound level meters right on property lines. And it was just amazing. In one direction, you would see desert for miles and as far as you could
see. And then behind me, I was sitting in snow and mountain, and it was it was gorgeous. Another project involved precious metals, a suitcase, and dynamite. We were building a bridge to go over an active mine and analyzing what kind of vibrational forces the the bridge needed to be designed to. And there's really well known classifications, right, for bridge design and seismic activity, but
this is blasting activity. And so for a few months, they got to measure blasting and record it via GoPro and via Gia Phone for vibration. And I got to analyze how the vibration through the rock and how far the rock throw went via GoPro. I remember one day I set up my rig, and I was just waiting in a clear area for the blast to go off. And then someone set down a a suitcase next to me, a heavy looking suitcase, and I heard a thud. And I just looked I looked next to me, and I realized
it was the detonator. As Gina's advanced in her career, she's gravitated toward a specialty that relates to her dream as a child. When I was pursuing my associates in music performance, I really thought that I was gonna go out and be a rock star. Growing up, I was heavily involved in the arts and performing arts and was part of a production company probably starting at the age of
16. Gina spent many hours in different types of performance halls where she took note of how different instruments sounded in different spaces. That eventually led to studying acoustics. I've always had a strength in math and really loved built spaces that I performed in. It became a love of myself performing and really the art of performance and then evolved into, well, how does what goes behind that performance?
She now leads the architectural acoustics practice at HDR, which can include health care facilities, data centers, industrial buildings, classroom settings, and correctional facilities. Gina said one of the first things to consider with acoustics inside a building is what might be creating noise outside the facility. On the architectural acoustic side, we can be brought on to a project very early on in the planning stages.
So we would discuss site evaluations, how this site may impact the acoustics, whether that be potentially high noise environment. Right? Is it near an airport or a highway? Is it near a freight rail line that has vibration? Then her team begins looking at how the space inside the facility will be used and what will impact acoustics. Space planning and planning for appropriate adjacencies
is going to be a number one. If you don't have a loud space next to a quiet space, then there wouldn't be a need for a high sound isolation system necessarily. And that doesn't just go for room functions. That also applies to the layout when you're talking about where do my mechanical units on the roof sit. Right? Is it over space that's noise sensitive, or are my duct mains dropping over a space that needs lower
noise levels? The acousticians work with other specialists as the project moves from overall space planning into more detailed design. And so we work with building owners and users, architects, interior designers, and structural engineers, mechanical engineers, then as the design of the facility progresses to help inform that design.
And so in later phases, we actually do quantitative analysis of the mechanical systems to calculate the noise into a space, the vibration impacting a space or coming out of a space, analyzing the finishes and how that impacts communications and reverberation, and then looking at the sound isolation systems of the interior partitions and exterior envelope. Gina's group uses a number of modeling programs to predict how a space will sound.
Often, clients want more than just a written report to convey the results. It's often difficult to interpret what words mean in terms of it is 30 decibels in this space and how does that translate to the actual oral environment? So we supplement that type of reporting, written reporting, and measurement with auralizations and audio examples of what a space might sound like or how systems are impacting
the the acoustics of a space. Using specialized software that can input a number of factors to produce samples of how a space might sound, which is called auralization. Most often, we are doing those simulations using the EASE software and modifying the finishes of the space, showing different examples of how adding more or less acoustic treatment or in acoustic treatment in different locations, how that would impact the acoustics of a
space. For example, within a performance space, an acoustician might take raw audio of a voice Sound. And simulate how it would sound from the right side of the main floor of the performance hall they're designing. Sound. Versus the sound on the left side of the balcony. Sound. Or how raw audio of an instrument sounds. And simulate that from the front row. And then the nosebleed seats. Spaces like that can involve some pretty interesting
clients. There was a recent design in the past five years that we did for the Walter Reed Medical Center, and it included an auditorium. And that auditorium will be used for both broadcast functions and live functions, and it's my understanding that the president will often speak from the auditorium. However, when you're designing a hospital, the acoustical goals are entirely different. An example of that could be looking at a patient room in a health care project, something like
that. We would be looking at noise control to provide a space that is calm and healing, where someone can rest. In addition to that, we're thinking about intelligible communication. Maybe there's messages being shared there or speech that's being shared there that needs to be heard very clearly in that patient room. So the challenge becomes achieving intelligibility within the room, but privacy from ears outside
the room. And then another consideration in that space would be, well, while I want someone who is in that room to very clearly hear what's being communicated. I don't want the people outside of that room to hear what's being communicated. So it's also isolating that room from the adjacent spaces. Depending on the purpose of a room, a simulation might compare raw audio of someone speaking. Dyloxetine. Loxetine. Versus someone speaking with background conversation in the space. Dyloxetine.
Loxetine. Versus someone speaking with background noise and reverberation. Diloxetine. Diloxetine. As health care providers imagine new types of spaces to promote healing, it can start to blend the acoustical considerations of different types of buildings. I have had medical facilities that have a lot of mixed use. One example of that is the think whole person project in the Omaha area. There was a theater where
videos would be played. There was a large six story atrium space that had multiple functions, patients moving through it as they were going to their provider spaces, had a cafe, and then also had the desire to have live performance and had a a permanent piano situated in it. And all of those functions were open to the atrium, which was adjacent to the provider spaces. So it was a very interesting mix of both performance type space and medical.
Office buildings and especially open offices or public spaces present their own considerations. In the context of sound masking systems and how they're used in design, they're typically not going to be just white noise. They're actually specific spectrums and tuned to provide more energy in certain frequencies than others, to provide more masking performance.
We'll often see those utilized in health care applications, in commercial building applications, in offices, And the function of those systems is to increase privacy either in open plan spaces or closed plan spaces by introducing, more background sound. That type of system can provide more privacy in an open space, but also provides a subliminal comfort. As an acoustician, there's a couple of things that are really difficult.
And one is to walk into, your open office and the sound masking is off because you are the first person to know, and it it drives me insane. The third area of the acoustics team focuses on traffic noise analysis work where Tim Casey began his career. My father was a electrical engineer at ENSF for most of my childhood, and I was around that field. I was around the rail
yards. I was able to see other things besides the electrical engineering part of it and was really intrigued and interested in the environmental aspect of engineering. That's Mike Parsons, a traffic noise analysis practice manager in HDR's Denver office. Mukul Pal, one of Mike's counterparts in Vienna, Virginia, experienced a similar family inertia into the world of engineering while growing up nearly 8,000 miles across the globe. I come from a family of engineers.
My dad, my uncles, even my sister, my cousin brothers. I mean, in India, it's a saying, right, that either you would be an engineer or a doctor when you grow up. So I kind of had, no choice up in the beginning. But just like Mike's, father, my dad is also an electrical engineer. Muckel started his career as a civil engineer. Much like his boss, Tim Casey, he ventured into traffic noise analysis through an EIS project in Chicago.
During his early projects, he met Mike, and they bonded over their similar backgrounds, which included a love of sports. As I got into my college career, I went to a division three school with the hopes of playing basketball, and the school did not have an engineering program. So after my first year, I started thinking that it wasn't really where I saw my future. And then after my second year, I was sure I was interested in doing engineering work.
Meanwhile, Mookal was raised playing entirely different sports. I was a very good cricket player. I I'm still a good cricket player, but I represented my college teams for badminton, cricket, and a lot of table tennis, volleyball, squash. I mean, lots of games. Mike began as an air quality engineer where he also found himself working EIS reports. So he began cracking open textbooks, staying up until midnight, and taught himself about
traffic noise analysis on the job. There are state and federal regulations that determine when a traffic noise analysis has to be done, and they have different types. And the type that drive these analysis is called a type one project. So that would be the addition of a traffic lane, a substantial change in vertical or horizontal alignment, and requirements like that. When a project has those requirements, by law, we have to do a traffic noise analysis.
So when you do that analysis, you predict whether the results you come up with will meet state and federal regulations. If they do, great. If not, then you have to design traffic noise abatement to help meet the requirements each state lays out. The first step of noise analysis involves identifying the noise receptors in the project area, the noise sensitive location such as people's backyards or a restaurant patio.
So once the project initiates and lands on our desk, just like a normal roadway improvement project, adding a new lane or we are building a highway on a a new alignment, we just take that study area and we determine various locations where we have to go and do some field noise monitoring.
Then we just take what we call ANSI nineteen eighty three type one or type two noise meters, and we deploy them in the field and do some, quick half an hour, twenty minute measurements on various different sites throughout the corridor to get a good sampling of what the ambient noise is in the corridor. From there, they get to work predicting how the noise levels would change after the project is built using software mandated by the Federal Highway Administration.
Then we bring back and we basically replicate the existing conditions in the traffic noise model PNM, and we take all the roadway design information and all that stuff with the existing conditions and code it in the traffic noise model. Then we put the traffic in there as well, and we go traffic speeds and all the grade features, some ground zones, some trees. And we try to replicate whatever is in the field, and then we let the noise model do its magic and predict the noise.
Because traffic noise fluctuates, the measurements are averaged to determine a baseline sound level. In traffic noise, we use the LAQ, which is equivalent continuous sound pressure level, which you can describe it as the average noise over a given period of time, which is an hour in traffic noise. So what we're comparing our predictions against is an hourly
average noise level. Well, you or I might not think about measuring sound beyond adjusting the volume on your smartphone or TV, Mookal and Mike described how sound level relates to traffic noise. Fun fact about traffic noise levels is the sound levels additions are based on the grid wake units. So if you add two fifty decibel sound levels together, it's not gonna give you a hundred decibels. It's gonna give you 53 decibels.
It's tough to explain when, you know, another way to look at it too is, like, it if you double traffic, it only raises noise levels three decibels, which is just barely perceptible to the human ear. Unlike Gina's simulations, the reports they produce don't usually include audio. They're filled with regulations and data from their noise measurements, often depicted using GIS to provide a more appealing visual communication of the results on a map.
And if those are within a threshold of three decibels, which is the normal rates that a human ear can perceive. Any change less than three decibels, the human ears, believe it or not, Danny, does not perceive the change. So anything above three decibels is what it perceives. And then we just take the model and do the build conditions. And based on our general NEPA process, we predict noise in the next twenty years, and there are federal guidelines of what the noise levels
have to be. When the new roadway is expected to exceed state abatement noise criteria or significantly increase noise levels by perhaps 10 to 15 decibels, for example, that's when the state DOT needs to investigate an abatement option and get public input. For the most part, the solution just comes down to the size of the sound barrier in the form of a wall alongside the interstate. There are other options that are considered, but usually none of them
really have any kind of staying power. For instance, with trees or vegetation, you have to have at least a hundred feet of dense trees or vegetation that are present year round. So that often is not the case in any of these project areas to provide any kind of noise reduction. A A lot of times, there's been a lot of studies that show those are they provide psychological benefit. If you can't see it, you don't get bugged and bothered
by it as much. Other options are berms, which while they work great, they often need a bigger footprint than a noise barrier. So those often aren't included in projects. You can create a buffer. So there's there's things like that. While they're looked at and examined, more often than not, they're not included in a project just due to space and footprint requirements.
Occasionally, a project might introduce some other variables into the equation, including one that brought Mike back to his days tagging along with his father at the rail yard. I worked on a cool one over the years. It was the BNSF BNSF Railway Logistics Park in Kansas City. It was a brand new facility they were building. And, there was a lot of different aspects that went into
this project. It had not only the rail line going in and out of this facility, but at the facility itself, it had big overhead cranes because this facility was bringing in these rail cars with with a cargo on it that they would have to take off, and then they'd load that onto semis, and they'd bring that to a logistics park and warehouse facility. Which included many more sources of sound than a six lane interstate.
So I had to predict noise from not only the trains, but the stationary and mobile equipment on the ground like the trains and the forklifts. And then we had noise from the the semi trucks going in and out of the warehouse and a bunch of different aspects that were creating noise and vibration for the receptors around the area. And, they were also building a new interchange as part of that
project. While the Federal Highway Administration and State Departments of Transportation govern roadway traffic noise, the Federal Railroad Administration and Federal Transit Administration have their own regulations for rail noise. This project fell somewhere in between. And there's not a lot of clear cut noise regulations that go along with a project like that. So when we do these traffic noise analyses, it's pretty straightforward with, you know, each state
has their own regs. You gotta follow it. But here, it was gonna get reviewed by the Kansas DOT, and I had all these different aspects and noise sources that were going into it. So I had to put together a plan and different regulations to follow and present that and get the DOT's buy off on it. And, ultimately, when we presented it to them, they bought off on it, and we did this analysis with all these different noise sources in the project area.
Sometimes the type of project is straightforward, but the mere size of the project makes it more memorable. One of the most recent projects that I did in North Carolina, it's a design build project about seven miles long, six lanes in each direction, and lots of receptors. And and, interestingly, analysis to be done on that project with keeping up with the design changes and things like that. In the end, we ended up with 24,000 linear feet of noise barriers that constitute about 425,000
square feet. So quite a massive project. With projects that size, finding alternative solutions to noise barriers can save millions of dollars. Mike mentioned one such project. There was a big design build analysis in Minnesota on T H 212, and they were really expanding the existing highway from a two lane road to a four lane controlled access highway on new alignment. So it was kind of cutting through all these neighborhoods, but there was enough
space. So when they did their preliminary design, they had noise walls everywhere throughout this project. But back then, they let me really help and guide the design a lot on eliminating these noise walls. So we're able to change the grade and go down further. We're able to use a lot of the extra soil when they reduce the grade to use as berms. And I was able to model these berms and really save millions in potential noise barrier costs. So that was kind of a fun
one. Though you may not see them, one of the latest innovations in traffic noise abatement is the introduction of clear walls. There are clear walls now. I think it's up in Wisconsin, if I'm not wrong. They have used a special material from plastic, which is clear. So from the driver's perspective, you are just driving and you won't realize that there is a wall unless there is a reflection of any of that sort. Spaces I've seen those walls are on
really beautiful environmental spaces. Like, there's a bay in Florida where they're been used, and they wanted the people coming you know, the walls went under the bridge and off the bridge, and they wanted the people to be able to see the water still and enjoy the water there. And more so, you know, everywhere I've seen them, they're not to block the pristine view of the environment that people have. If you study traffic noise for a living, then, yes, you also begin to take note
of it when you're not working. Oh, absolutely. You know, you you constantly are are, you know, judging some of the levels, of course. Nowadays, even there are these apps, that you can download on your phone to get an average noise levels wherever you, want to measure. As Mike reminds us, no matter the profession, isn't that something that everyone does? I mean,
I'll tell you what. I grew up with an electrical engineer father who would always point out power lines, and I'm married to a dentist who always or not always, but occasionally points out things about people's smiles or teeth. So I'm always like, why would you do that? But now I always find myself looking at noise walls, especially ones that have, like, some cool aesthetic treatments. Right? Then I find myself noticing that everywhere I go. Like, oh, that's
a ugly noise. Well, that's a pretty noise. Well, yeah. You know, my young self would be disappointed in my old self, but, you know, here you are. And once again, Mookle is finding the apple doesn't fall far from the tree. The kid who is six years old, of course, you know, that's the age. He's always inquisitive. Right? So you're driving and he is he has come to know, like, you know, what, dad does. And he is constantly pointing. Papa, that's the wall that you built. Right?
So I'm like, oh my god. For more information, visit hdrinc.com/speakingofdesign. You'll find pictures, bios of our guests, and links to related articles. And be sure to subscribe and drop us a review on your favorite podcast app. Thanks for listening. Special thanks to Tim Casey for lending us his music for this episode. You'll find more from Tim Casey and the Martyrs anywhere that you find music online. Additional thanks to Amanda Weiss.