bluuebunny/crossref_metadata_2025 huggingface dataset:
Source Characterization using Inverse Numerical Acoustics based on Pellicular Modes
Authors: Yan Xin , Herrin David , Ghaisas Nikhil
Published: June 2023

An inverse method is used to characterize radiating noise sources. Measurements of the sound pressure in the field are used to reconstruct the vibration on the surface of a vibrating structure. The basis functions for this inverse calculation are pellicular modes. These modes are calculated
by assuming that there is a thin air envelope around the vibrating structure. The acoustic modes are calculated using this air envelope and the acoustic mode shapes are then assumed to be structural modes. Though not the actual structural modes, these modes are easily calculated and form convenient
basis functions. This procedure is demonstrated on two examples. The first is a small electric motor and the second is a generator set. It is demonstrated that the procedure can be used to accurately characterize the sound radiation from a source.
What is Average Pavement? A Critical Commentary
Authors: Busch Todd
Published: June 2023

The Traffic Noise Model (TNM) is used to forecast traffic noise levels. When applied to federally funded projects, a user of the software is expected to apply "average" noise emissions for pavements. This "average" is an intermediate value that in some manner falls
in between the higher noise emissions of Portland Cement Concrete (PCC) and lower emissions of Dense Grade Asphalt Concrete (DGAC). The purpose of this paper is to illustrate some curious characteristics of "average" pavement as it is employed in the TNM. Among these characteristics
are what appear to be different methods for averaging the noise emissions for various vehicle types, such as automobiles, medium trucks, and heavy trucks. The inquiry concludes with an attempt to clarify exactly what constitutes an "average" when it comes to pavement noise emissions..
Relationship between the normalized impact sound pressure level (NISPL) and the transmission loss (TL) of a floor ceiling assembly
Authors: Golden Matthew
Published: June 2023

The relationship between the normalized impact sound pressure level (NISPL) and the sound transmission loss (TL) of a floor ceiling assembly has been understood since 1963 (Heckl, and Rathe) and confirmed in 1971 (Ver), both for concrete based buildings. This concept has even made its
way into ISO 12354-2. This paper will analyze approximately eight hundred floor/ceiling assemblies that Pliteq has measured in the lab to see if this relationship holds for other types of assemblies and where it might fall short. In a related topic, there has been discussion at ISO to create
a delta sound reduction index (R) and normalized impact sound level (Ln) for added ceilings similar to the Delta IIC for floor coverings. The Ln/R are similar to the TL and NISPL in ASTM. The same data set will be queried to see if this is a valid approach for real world constructions in North
America.
Validation study of in situ sound absorption measurement
Authors: Kim Jeong-Woo
Published: June 2023

An in situ acoustic tube measurement is a non-destructive way to measure the sound absorption coefficient of a material. This method is practical for obtaining sound absorption in cases where it is not straightforward to sample specimens in applications such as automobile interiors,
room walls, ceilings, or carpeted floors. However, the in-situ method's limitations lie in measurement errors due to the sound energy leakage through the open boundaries within the materials. In addition, it is not straightforward to provide a general correction factor compared to the standard
in-tube method because the errors depend on various factors such as material characteristics, material flow resistance, installation conditions, pipe flange size, etc. The aim here is to provide practical guidelines for reducing in-situ error by analyzing and comparing that procedure with
the standard in-tube method. Here, in-tube and in-situ methods were used to measure and they were then analyzed by creating FEM-based acoustic tube and poro-elastic material models. The effect of material flow resistivity and flange thickness were investigated and reported.
An application of Next Generation Concrete Surface texture to an existing concrete pavement
Authors: Janello Carrie , Donavan Paul
Published: June 2023

Between 2011 and 2013, the California Department of Transportation (Caltrans) installed New Generation Concrete Surface (NGCS) along a stretch of State Route 113 (SR 113). In the fall of 2013, this pavement was evaluated using the on-board sound intensity (OBSI) testing method. NGCS
is a flush ground and grooved surface developed at Purdue University's Herrick Laboratory in 2004. This innovative, low noise grinding texture has minimal positive texture with good microtexture, which was intended to reduce noise levels at low frequencies, and has great macrotexture, which
was intended to reduce noise levels at high frequencies. To evaluate the acoustic longevity of the pavement, OBSI testing was again completed in early 2023, and the long-term results are discussed in this paper. Additionally, the acoustic longevity of the NGCS pavement is compared to the long-term
OBSI results collected between 2003 and 2010 on a ground concrete surface installed along Mojave SR 58. In 2022, NGCS was applied on a section of the U.S. 101 Freeway in Carpinteria in Southern California. The results of these measurements and the noise reductions achieved are also presented.
Noise suppression plan for demolishing a parking garage
Authors: Marshall Steven
Published: June 2023

The headquarters of a pharmaceutical corporation planned to replace a parking garage with additional office buildings at the site in Silver Spring, Maryland. Neighbors adjacent to the location included private offices, public buildings, and residences. In order for approval to pursue
construction projects in Montgomery County, Maryland, a Noise Suppression Plan must be submitted to the Montgomery County Department of Environmental Protection. The contractor responsible for demolishing the parking garage hired Scantek, Inc. to build and compose the Noise Suppression Plan.
The Noise Suppression Plan offered a three-prong approach to insure a maximum sound level of 75 dBA at a 500-feet radius around the construction site during normal business-time period. The noise sources (construction equipment) were addressed by optimizing operations such as separating the
noise sources (activity zones) within the site and limiting engine throttles (rpm) powering the hydraulic pumps. Additionally, acoustic barriers were installed for the entire perimeter of the construction site. Finally, acoustic absorption bulk-material was piled at strategically locations
to reduce sound reflections and acoustic reaction energy. The construction company sent a notice to all neighbors adjacent to the parking garage ahead of the demolition to inform of schedules, expectations, and contact information. The demolition moved ahead without notable complaints from
the neighbors.
Statistical energy analysis simulation of an air-handling cabinet
Authors: Smither Matt , Herrin David
Published: June 2023

Statistical energy analysis (SEA) is a vibro-acoustic modeling technique suitable for systems where high modal densities exist. Traditionally SEA is used for predicting system response in higher frequency bands. However, for systems such as an air-handler that contain large, flat panels
constructed of sheet metal the usefulness of SEA stretches into mid and lower frequency bands as well. Measured results of an air-handling cabinet were obtained by spatially averaging accelerations of cabinet surfaces caused by an input of white noise into the cabinet side by a shaker. Energy
from each sub-panel of the cabinet was normalized with the panel into which the energy was input for easy comparison with modeled data. A simplified model of the air-handling cabinet processed in VA One software yielded results generally within 10 dB of measured results. Some lower frequency
band limitations were realized due to cabinet geometry and construction. These results focus primarily on the structure and less so on the acoustic volume of the air-handling cabinet.
A constrained multi-channel hear-through filter design approach using active control formulations
Authors: Kim Juhyung , Zhuang Yongjie , Liu Yangfan
Published: June 2023

In many daily communication environments, especially during the pandemic era, partitioning structures are placed between people for security or virus concerns, for example, partitions in classrooms, banks, retail stores, etc. . Distortion occurs when sound propagates through these partitions
can cause distractions in communication and degrade the service quality. In the current work, a constrained multi-channel active hear-through system is proposed to provide a solution to provide more natural sound communication environments and prevent sound distortions due to portioning structures.
The proposed method can preserve both the spectrum and the spatial distribution of the original sound field (the sound field when the partition is absent). This research opens the potential for future development of multi-channel two-way communication systems and improvement in existing augmented
reality techniques. Experimental results show that, compared with the traditional direct inverse filter design method, the proposed method can reduce the comb-filtering effect effectively. The constraints applied to the filter design procedure can also prevent instability caused by the acoustic
feedback loop.
Evaluation and mitigation of outdoor live music
Authors: Singleton Herbert
Published: June 2023

Live music is hosted at many small restaurants and breweries as a means for attracting customers and helping to expose patrons to local bands. Outdoor live music, especially during warm spring and summer seasons provides flexibility for venues in terms of seating capacity, patron comfort,
and the integration of natural scenery. However, sound from outdoor entertainment can be a vexing problem for the surrounding community, especially for late evening and nighttime performances. In response to community concerns, outdoor live music venues located in three different communities
(rural, small town urban, and waterfront) were each required to provide in-situ demonstrations to assess the effect of outdoor music on nearby homes. The effectiveness of these demonstrations, along with an analysis of mitigation measures, is discussed.
Investigation of the impact of environmental conditions on the vibration mitigation performance of typical commercial under ballast mat materials
Authors: Bradley Colin , Havin Josh
Published: June 2023

The performance of under ballast mats (UBMs) in mitigating vibrations caused by regular rail traffic has been the subject of numerous studies. However, most of these studies have focused on the impact of design and material properties on the vibration attenuation characteristics of
UBMs, with little attention paid to the influence of environmental factors such as temperature, freeze/thaw cycling, and weathering. In this paper, we present the results of an investigation into the effect of environmental conditions on the vibration mitigation performance of typical commercial
UBM materials including rubber and closed cell polyurethane elastomer. We conducted controlled laboratory experiments in which we exposed UBM samples to a range of simulated environmental conditions. The results of these experiments were compared to the results of tests conducted under standard
laboratory conditions to evaluate the impact of the environmental conditions on the vibration attenuation performance of the UBMs. The results of this investigation have important implications for the design and selection of UBMs for use in railway systems, particularly in regions with extreme
environmental conditions.
Assessing challenges due to HVAC design constraints and their effects on VAV terminal unit noise - lessons learned from recent projects
Authors: Pyper Ted , Porter David
Published: June 2023

For most projects requiring HVAC noise analysis, designers can reliably account for projected noise contributions from VAV terminal units. However, the authors' recent experiences on projects with challenging constraints (e.g., renovations to existing HVAC systems, prohibition of duct
liner and/or flex duct, and restriction to packless/no-media silencers), show that manufacturers' published data are not always sufficient. In the provided project examples, published noise levels for terminal units have required greater consideration because of complexities of the HVAC systems
and building conditions. A variety of contributing factors are discussed, as well as the challenges of in-field testing, diagnostics, and troubleshooting. Key takeaways include the need for coordinating with mechanical engineers about the accuracy of system set points; improving assumptions
made about system pressure drops and manufacturers' data; and identifying project types that require greater consideration when using manufacturers' data.
Simulating electrified powertrain noise and vibration measurement signals for machine learning based fault diagnosis applications
Authors: Lee Joohyun , Liu Yangfan , Davies Patricia , Bolton J.
Published: June 2023

Machine learning classification is a common method for vehicle noise and vibration (N&V) fault diagnosis which helps improve vehicle safety, comfort, and reduce maintenance cost. To improve the accuracy of classification, the model requires sufficient training data which is often
expensive and time-consuming to acquire. A possible solution to resolve this limitation is to extract representative features from measurement signals and generate realistic simulatied signals based on a smaller set of high-quality N&V measurement signals. A method to simulate N&V
measurement signals of rotating machineries such as electrified powertrains is proposed. In its feature extraction process, tonal and broadband components of measurement data are separated. After the separation, time-varying tonal amplitudes, broadband spectra, and various related statistical
features are extracted. In the simulation process, tonal and broadband signals were simulated using the extracted features with random variations added to each feature. In the current work N&V measurement signals of rotating machinery are simulated with relatively low speed fluctuation
and results are presented.
Requirements and best practices for traffic noise model validation
Authors: Burge Paul , Greer Gayle , Muirhead Matthew , Mahoney Jessica
Published: June 2023

The exercise of validating a predictive model typically consists of modeling an existing real-world condition and predicting some resulting quantity of interest, and then comparing the predicted results to actual measured values for the same condition within a specified margin of error.
In the case of road traffic noise models this would include modeling the characteristics of the existing roadway condition (geometry of the roadway network; number, vehicle type and speed of vehicles using the roadways; pavement types; intervening terrain; etc.) and comparing the resulting
predicted noise level to actual noise measurements for the same conditions. In this paper the authors will provide a concise background of the validation purpose and process as well as a review of agency requirements and best practices for traffic noise model validation procedures.
Improving Speech Intelligibility from PA Systems in Transportation Terminals
Authors: Glickman Gary , Murphy Patrick , Jue Deborah
Published: June 2023

ACRP 175 was published in 2018 and provides basic guidelines for design, installation, and operation of public address systems in airport terminals. There are approximately 400 airports in the US, and with over 550 underground stations and 2,600 above ground stations in the US , many
of these guidelines developed for airports can also be easily adapted for these transit stations. This paper provides an overview of ACRP 175 guidance with a focus on key factors for successful design and commissioning. As part of the research acoustic field studies were performed at six airports
and a total of 45 different spaces including ticketing, concourse, gate lounges, food courts, arrival/departure halls, baggage claim, and curbside locations. We describe experience using ACRP 175 on current design-build projects and discuss other relevant industry standards.
Design-build noise policy - what's fair?
Authors: Avery Kenneth
Published: June 2023

The New York State Department of Transportation (NYSDOT) is implementing a design-build delivery process on projects involving noise barriers that requires design-builders to provide Final TNM design year with noise barrier noise levels that are equal to or less than the corresponding
Preliminary TNM design year with noise barrier noise levels determined in the NEPA environmental document. The NYSDOTs first use of the design-build delivery method was the $3.9B New NY Bridge project implemented by the New York State Thruway Authority (NYSTA). That project included
a significant investment in noise barriers on the Rockland Landing. The New NY Bridge (NNYB) project served as a test case at a time when a well-developed design-build noise policy did not exist. In the absence of a definitive design-build noise policy, the noise barriers originally offered
by the design-builder, while providing significant noise reductions, failed to meet all the environmental commitments made to all benefitted receivers as documented in the Final Environmental Impact Statement and Record of Decision (FEIS/ROD). Working with FHWA and NYSDOT, the NYSTA reached
agreement with the design-builder to construct noise barriers that provided the same future design year with noise barrier noise levels that were provided in the noise study that supported the FEIS/ROD. Since construction of the New NY
Analysis of PMSM NVH performance in electric propulsion systems using FE models
Authors: Bhyri Rajeswara , He Song
Published: June 2023

The stator of the PMSM is the main transfer path for the Electro Magnetic (EM) force from stator teeth to the drive unit (DU) through its mounting ears. First, a FE model of full winding stator model along with connection ring is analyzed for modal behaviors. Time domain EM force excitations
are converted into frequency domain and applied at the stator teeth. This enables stator mounting forces analysis at all critical NVH orders. Next, the detailed FE modelling approach is compared with response calculated form a simplified modelling approach, with stator end windings modelled
as lumped mass and inertia to reduce computational time. The comparison study of two approaches clearly shows the benefits of using simplified FE models for studying motor whine with reduced modelling and computational costs. Furthermore, the frequency-dependent stator damping measured from
modal test is applied in electric DU analysis to evaluate NVH performance excited by motor EM force excitations using simplified stator model. The sound power level radiated from the DU and the mount vibration response show negligible influence of stator damping at DU unit level NVH response
in the low frequency range. Analysis and test results correlate reasonably well at the dominant motor whine orders for the DU, which validates the proposed method.
Characterization of unmanned aircraft system acoustic noise
Authors: Rasband Reese , Mobley Frank , Reeves Mason
Published: June 2023

UAS (unmanned aircraft systems) are used in a variety of commercial and military enterprises. In military settings, being able to identify location as well as number of enemy UAS can lead to stronger strategic positioning or appropriate countermeasures. In community settings, UAS can
be a source of annoyance. Recently, AFRL measured three different UAS flown by pilots from Sinclair Community College. These UAS included various sizes and blade amounts. They were flown back and forth through an array of 20 acoustic sensors at nominal thrust. In addition to flying through
the array, they were also flown at heights of 15 feet and 100 ft above the array. Using both telemetry and acoustic data, spherical source characterizations of the systems can be derived. These three-dimensional characterizations can lead to a better understanding of UAS acoustics as well
as improved measurement design. This study describes the recent measurement in detail, some preliminary analysis, and the lessons learned. Future analysis and testing will promote acoustic identification of a larger variety of UAS.UAS (unmanned aircraft systems) are used in a variety of commercial
and military enterprises. In military settings, being able to identify location as well as number of enemy UAS can lead to stronger strategic positioning or appropriate countermeasures. In community settings, UAS
Vibration modeling of buildings with composite floors
Authors: Layman Christopher , Glickman Gary , Bensing Silas
Published: June 2023

Profiled composite floors (ribbed concrete slabs on corrugated steel decks) are commonly used in steel framed buildings. However, complicating the dynamic modeling of such floors is their apparent stiffness anisotropy due to the periodically spaced ribs. In this paper, approaches are
presented to obtain the effective, flat-plate properties of composite floors to predict floor vibrations for two building case studies. Measured floor vibrations for the case studies are then compared to the models.
Air vent shape optimization with metamaterials.
Authors: Lizotte Marco , Panneton Raymond , Piaud Jean-Bernard
Published: June 2023

Heating, Ventilation and Air Conditioning (HVAC), are crucial in every building for the well being of the occupants. While these equipments take care of the air quality with exhausting polluted air out and bringing fresh air in, they can let a polluant in: noise. Noise can have non-physical
effects like disturbed sleep, cognitive problems or even influences on heart diseases. Recent developments in the acoustic field shown the use of metamaterials that can reduce noise while keeping good ventilation. The sonic crystals, disposed in a certain pattern following the Bragg's law,
can be tuned to reduce noise on a wide frequency band. The design of an air vent, known as a metacage, was made by using open source numerical simulations. Based on a numerical plan and optimization methods, this study's goal was to find the optimal solution for the HVAC to reduce noise while
minimizing ventilation loss. Following the simulations results, the metacage generated was 3D printed for validation in the laboratory, showing the corroboration with the simulations. The final results show third-octave bands with a TL peak over 10dB and an average of 3dB for all the others
bands up to 10kHz. All this while keeping minimal ventilation loss.
Simulating vibro-acoustic damping of bubbles in fluids
Authors: Kappagantu Ramana , Dominguez Elvis
Published: June 2023

Bubbles in fluids are common occurrence due to impurities, thermal or flow variations. They are sometimes considered detrimental to the flow and more importantly surrounding structural integrity. On the other hand, bubbles were used positively towards damping vibrations in fluid filled
structures [1] and as barriers or curtains in the removal of plastic waste from water ways [2] and also in noise attenuation from offshore windfarms [3]. In the latter two cases, engineers hypothesized these curtains help marine life from sound pollution from surrounding machinery and ships.
In this paper the authors discuss two cases to study the effect of bubble size and bubble density. In the first experiment a curtain of air bubbles was introduced in a water body and sound transmission loss (STL) through this curtain was studied. In a second experiment, a stainless-steel tank
filled with liquid mercury is infused with helium bubbles and the vibration levels were monitored.
Long-term environmental noise measurement methods for industrial noise sources
Authors: Nelson David
Published: June 2023

Industrial noise sources can impact nearby residential communities, especially in rural areas. In order to assess the situation after commissioning, plant noise must be reliably differentiated from prevailing ambient, transient environmental noises, and weather-related events. Continuously
attending such measurements is generally impractical. On the other hand, classifying events by eyeballing a stream of Leq values after the fact isn't sufficiently reliable in most cases either. An effective approach is presented that involves measurement and statistical, observational, and
analytical methods to perform much of the work in an automated fashion. Methods include statistically excluding transients from the Leq, filtering to eliminate birds and bugs, spectral characteristics of wind events, and potential spectral identifiers indicative of operation. Classifications
are confirmed by listening to periodic and/or event-driven audio segments. This approach works best when both the plant noise and prevailing ambient are quasi-steady; plant-generated transients and weather events may require manual reclassification. Examples from long-term environmental noise
studies are provided. The methods are neither dramatic nor novel but their effectiveness in combination may be useful, especially for those new to this type of work.
Case study: measurements and modeling of noise from pickleball versus tennis play, and estimation of proposed noise reduction measures
Authors: Greene Mike , Leech Jonathan , Burke Connor
Published: June 2023

Noise measurements were conducted of play during tennis and pickleball matches for the purposes of comparison and analysis. Modeling was conducted using a 3-D predictive noise modeling software package, and potential noise reduction measures in the form of absorptive noise barriers
were modeled in order to assess the potential benefits at an adjacent residence. The paper presents the results of the analysis.
Active noise cancellation with FPGA - practical considerations
Authors: Wang Tongan , Bohanan Scott
Published: June 2023

Active noise cancellation (ANC) has been successfully applied to mitigate noise in many applications, such as in headphones. Besides algorithm development and computer simulation, developing an ANC system involves many practical considerations. From hardware selection to fixed-point
implementation, many practical constraints can prevent a good algorithm from functioning properly on the hardware. This paper discusses the development of an ANC prototype system using Field-Programmable Gate Array (FPGA) hardware. The paper also reviews several practical issues that were
encountered in the development of the prototype, the symptom and root cause of each issue, and the solutions to mitigate them. The final ANC prototype system successfully cancels noise of both tonal and broadband contents.
Case study of construction issues affecting speech privacy in legal offices
Authors: Pietrusinski Nick , Hirsh AnnMarie
Published: June 2023

During the design phase of a project, theoretical calculations for how a space will acoustically perform are often used. However, improper construction practices and other factors such as incompatible manufacturer combinations can lead to large discrepancies between theoretical performance
and field-tested performance. The project in question consisted of a renovation of an existing legal office suite with a waffle ceiling and wide window spans. The primary acoustical concern was sound isolation from office to office and from private offices to open office space. A confidential
level of speech privacy was the design goal as the suite contained multiple legal consultation rooms. Existing exterior glazings spanned the length of multiple offices, so an acoustical mullion was specified. Full perimeter door seals and automatic door bottoms were also installed. This paper
details how the measured performance of this suite of offices was significantly lower than the designed Sound Transmission Class (STC) rating due to issues with the acoustic mullion installation as well as different door seal, door frame, and door manufacturer incompatibilities.
Evaluating the Vibration Performance of Existing and Future Building Structures for Laboratory Tenants
Authors: Brush Ethan
Published: June 2023

Major cities were recently experiencing a large demand for life science and biotech spaces, which led to the possibility of using existing building spaces or new developments for lab space rather than their original or intended usage. The vibration requirements of a building are a critical
concern when it is intended for laboratory use - these requirements often flow down and affect the structural design. For buildings that were not designed as sensitive facilities, an evaluation process is often necessary to assess suitability. Fitness-related amenity spaces, often desired
by developers, further complicates the design of vibration sensitive facilities. Whether it be new construction or re-use of an existing building, the vibration consultant plays a key role in the ultimate success of the facility. This paper discusses the latest test and analytical methods
being used by the author for evaluating the vibration performance of existing and future building structures. The main vibration sources under consideration are environmental, footfall activity, and fitness amenity spaces.
Experimental dynamic flow characterization of hydraulic bushings
Authors: DeGarmo Kenneth , Kennedy Michael , Fredette Luke
Published: June 2023

The dynamic properties of hydraulic bushings are often modeled in the time and frequency domains with low-order, lumped-parameter models, typically assuming steady, developed flow in their fluid passages, whereas in situ flow conditions are unlikely to meet such criteria. Hydraulic
bushings exhibit tuned properties emerging from nonlinear interactions involving these flow characteristics, so higher resolution descriptions of the underlying physics are needed under realistic flow conditions. This paper discusses an approach to isolate the fluid passage features in production
bushings to enable experimental characterization for steady, oscillatory, and transient flow. More robust models of dynamic responses in the time and frequency domains are expected to result from this more precise determination of each flow path's contribution to the nonlinear system response.
An apparatus capable of generating steady and dynamic flow is proposed, and some validation data is given to demonstrate the functionality of the experiment. Some challenges with the approach are considered, including the system's hydraulic compliance and cavitation. The flow testing apparatus
is used on an example two-passage production bushing adapted for controlled steady or dynamic flow through one or both flow paths. Finally, some nonlinear flow properties of a typical hydraulic bushing's flow passages are given.
Dynamic time warping for transient noise classification
Authors: Dare Tyler
Published: June 2023

Dynamic time warping (DTW) is a method of defining the similarity of waveforms. In contrast to cross-correlation, DTW allows signals to be stretched and compressed ("warped") in order to find the best match possible. Once a metric of similarity has been defined, a set of many
signals can be partitioned into groups that are mutually similar. Separating signals into similar groups can be a useful first step in finding potential sources of noise. In this paper, the theory of dynamic time warping is reviewed with examples. DTW was used to partition recordings of transient
percussion sounds into groups, with each group representing a source instrument. After partitioning, an "average" signal for each group was calculated, which was then used to compare the different sources of sound.
User-defined vehicle types in TNM 2.5 for modern vehicles
Authors: Martin Cole
Published: June 2023

Electric vehicles are currently estimated to account for approximately 1.5% of 250 million vehicles on US roadways. While a small number now, the market share for electric vehicles in the US is approximately 5% and steadily growing, with some estimates suggesting up to 20% of all cars
on the road by 2025 and 40% by 2030. Unfortunately, TNM REMELs do not account for electric vehicles or other modern advances in combustion and hybrid engines. Updates to TNM are a fairly lengthy process, often requiring several years before the next iteration is tested and approved. Therefore,
the validation process will become increasingly difficult as adoption of modern vehicle types increases. Utilizing the user-defined vehicle option within TNM 2.5, modern vehicle types will be presented as a possible alternative when validating TNM models, with the expectation that the measurement/model
offset would be improved by accounting for technological advances since the development and release of the software.
An app for nationwide dynamic traffic noise prediction
Authors: Cook Mylan , Gee Kent , Transtrum Mark , Lympany Shane
Published: June 2023

Despite being so pervasive, road traffic noise can be difficult to model and predict on a national scale. Detailed road traffic noise predictions can be made on small geographic scales using the US Federal Highway Administration's Traffic Noise Model (TNM), but TNM becomes infeasible
for the typical user on a nationwide scale because of the complexity and computational cost. Incorporating temporal and spectral variability also greatly increases complexity. To address this challenge, physics-based models are made using reported hourly traffic counts at locations across
the country together with published traffic trends. Using these models together with TNM equations for spectral source emissions, a streamlined app has been created to efficiently predict traffic noise at roads across the nation with temporal and spectral variability. This app, which presently
requires less than 700 MB of stored geospatial data and models, incorporates user inputs such as location, time period, and frequency, and gives predicted spectral levels within seconds.
Considerations in Regulating Anthropogenic Noise in Wilderness Areas, State and National Parks and Forests
Authors: Casey Tim
Published: June 2023

Is anthropogenic noise (i.e. from mining or industrial activities) heard in "natural settings" such as wilderness areas, national parks, state or national forests, from activities outside the boundaries of those designated areas, a problem? Congress established a goal of protecting
the natural wilderness character of wilderness-designated lands in the Wilderness Act of 1964. The National Park Service Director's Order #47 (2000) established operational policies that require, to the fullest extent practicable, the protection, maintenance, or restoration of the natural
soundscape resource in a condition unimpaired by inappropriate or excessive noise sources. So does that mean that anthropogenic noise from outside the boundaries of these types of designated areas is an impact by virtue of its nature? This paper explores that topic and answers that question
in an attempt to provide clarity for future evaluations of environmental noise in wilderness areas, state, and national parks, and state and national forests.
Using barrier-adjacent measurements and predictions to determine effects of small gaps in highway noise wall
Authors: Bliss Colin , Rochat Judy
Published: June 2023

Noise walls are installed along highways to reduce highway traffic noise in adjacent communities. Based on installation or aging effects, some noise walls contain small gaps between panels. Applying traditional barrier insertion loss measurements comparing sections with and without
gaps may not be possible due to site conditions. For this study, barrier-adjacent sound levels were collected at gap locations and comparable reference (non-gap) locations to determine the gap effect immediately behind the barrier. Two methods are then applied to determine how these gap effects
translate to nearby communities. Both broadband and spectral sound levels are analyzed to determine that the effects of a small gap (up to 0.5 inches in height and 10 inches in length) can be up to 2 dB near the barrier but diminish rapidly with distance.
Characterization of Road noise levels increase due to installation of transverse rumble strips
Authors: Aly Kareem , Vairo John , Choy Mervyn
Published: June 2023

Transverse rumble strips have been widely employed as a means to warn distracted. Noise emissions from traveling over the rumble strips negatively impact surrounding communities. Moreover, the distinguished noise characteristic of rumble strips makes this noise a nuisance to the surrounding
community. Measurements of the noise emission generated from vehicles passing over transverse rumble strips have been completed adjacent to the 18-rumble strips. To determine the impact of the rumble strips on noise generation, sound level measurements were taken of vehicles traveling over
smooth pavement prior to travelling over the rumble strips shortly after. The measurements were completed for uncontrolled normal road traffic and for controlled vehicle pass-by, where the vehicle speed was steady and controlled. The overall noise emission from the transverse rumble strips
results with a 3-9 dB increase above the corresponding vehicle noise emission Leq on smooth pavement. The corresponding sound exposure level is calculated. The increase in the noise emission is largely dependent on the vehicle type and not correlated to vehicle speed. The rumble strip noise
is characterized as quasi-steady impulsive sound for receptors, which may require an additional noise penalty. The results show that the rumble strips noise does not have any distinct tone.
Development of Active Noise Control System Optimized for Road Noise Reduction
Authors: Sakamoto Kosuke , Kobayashi Yasunori
Published: June 2023

In this paper, a newly developed Active Noise Control (ANC) system is introduced, that effectively reduces road noise, which becomes a major issue with electrified vehicles, and that enhances vehicle interior sound levels matching seamless acceleration by electric drive. Conventionally,
reducing road noise using ANC requires numerous sensors and speakers, as well as a processor with high computing power. Therefore, the increase in system cost and the complexity of the system are obstacles to its spread. To overcome these issues, this system is developed based on four concepts.
The first is a modular system configuration with unified interface to apply to various vehicle types and grades. The second is the integration and optimal placement of noise source reference sensors to achieve both reduction in number of parts and noise reduction performance. The third is
the application of digital communications that combine power superposition, low latency, and high throughput to reduce wiring. The fourth is the development of control technologies that specialize in in-vehicle acoustic characteristics to achieve both computational efficiency and noise reduction
performance. The one is a technology to integrate control paths based on the sound field mode characteristics in the vehicle cabin, and another one is the frequency band restrain control technology that matches speaker output characteristics. It is confirmed that this proposed system achieves
quietness improvement equivalent to the difference of vehicle segmentation with a minimum system configuration, and that this system has a high superiority in weight efficiency compared to conventional vehicle body measures.
Research on the Harmonics-Based the Optimization Algorithm for the Active Synthesis of Automobile Sound
Authors: Xie Liping , Chen Wan , Liu Zhien , Lu Chihua
Published: June 2023

The technology of active sound generation (ASG) for automobiles is one of the most effective methods to flexibly achieve the sound design that meets the expectations of different user groups, and the active sound synthesis algorithms are crucial for the implementation of ASG. In this
paper, the Kaiser window function-based the harmonic synthesis algorithm of automobile sound is proposed to achieve the extraction of the order sounds of target automobile. And, the suitable fitting functions are utilized to construct the mathematical model between the engine speed information
and the amplitude of the different order sound. Then, a random phase correction algorithm is proposed to ensure the coherence of the synthesized sounds. Finally, the analysis of simulation results verifies that the established method of the extraction and synthesis of order sound can meet
the requirements of target sound quality. The algorithm proposed in this paper can be used for the development of real-time engineering of ASD technology for real vehicles.
The Influence of Contextual Non-Auditory Factors on Drone Sound Perception
Authors: Aalmoes Roalt , Bruijn Bram de , Sieben Naomi
Published: June 2023

New forms of air transport are expected to arrive in the next decade: development of unmanned multi-rotor equipped drones, are expected to be used for not only observation purposes, but for postal package delivery as well. The impact of close-flying drones near communities is still
not fully understood. One of the main concerns for public acceptability is noise impact as it may negatively affect human health and well-being. Prior research shows that non-acoustical factors play an important role in the perception of noise. A laboratory study was conducted to evaluate
different subjective factors to examine their influence on noise annoyance: education on useful applications of drones (positive framing), rural versus urban environments, different visually modelled sizes of drones, and the visual noticeability of drones. Participants of the study evaluated
scripted drone events using a Virtual Reality headset with a sound simulation system. Results show that drones flying in a rural environment were perceived as significantly louder, more annoying, and more noticeable compared to an urban setting. Also, noticeability of a drone significantly
predicted annoyance and loudness. However, the size of the drone influenced noticeability, but not annoyance. Unexpectedly, the positive framing did not have a measurable influence in this study.
A Psychoacoustic Test for Urban Air Mobility Vehicle Sound Quality
Authors: Boucher Matthew , Rafaelof Menachem , Begault Durand , Christian Andrew , Krishnamurthy Siddhartha , Rizzi Stephen
Published: June 2023

This paper describes a psychoacoustic test in the Exterior Effects Room (EER) at the NASA Langley Research Center. The test investigated the degree to which sound quality metrics (sharpness, tonality, etc.) are predictive of annoyance to notional sounds of Urban Air Mobility (UAM) vehicles
(e.g., air taxis). A suite of 136 unique (4.6 second duration) UAM rotor noise stimuli was generated. These stimuli were based on aeroacoustic predictions of a NASA reference UAM quadrotor aircraft under two flight conditions. The synthesizer changed rotor noise parameters such as the blade
passage frequency, the relative level of broadband self-noise, and the relative level of tonal motor noise. With loudness constant, the synthesis parameters impacted sound quality in a way that created a spread of predictors both in synthesizer parameters and in sound quality metrics. Forty
subjects listened to the suite of UAM noise stimuli in the EER and judged each sound individually on a standard scale of annoyance. Additionally, a subset of the UAM noise stimuli were compared to a reference sound that varied in loudness. From these responses, the relative effect of changes
in loudness or changes in other sound quality metrics on annoyance was evaluated. This paper covers background and motivation for the test, details of how the sound stimuli were generated, and details of the test design and execution. Test results investigate how sound quality may affect perceived
annoyance to UAM vehicle noise, indicating the importance of sharpness, tonality, impulsiveness, and roughness on annoyance to UAM noise.
Advances in the Measurement and Human Response to Noise of Unmanned Aircraft Systems
Authors: Green Nathan , Ramos-Romero Carlos , Torija-Martinez Antonio
Published: June 2023

The sound produced by Unmanned Aerial Systems (known as UAS or Drones) is often considered to be one of the main barriers (alongside privacy and safety concerns) preventing the widespread use of these vehicles in environments where they may be in close proximity to the general public.
To better understand the potential environmental noise impact of commercial UAS operations, work undertaken by the University of Salford has focused on two key areas. Firstly, how to characterise and measure the sound produced by UAS during outdoor flight conditions and secondly, better understanding
of the dose response of UAS noise when the listener is in either an indoor or outdoor environment. The paper describes a field measurement campaign undertaken to measure several UAS performing flyovers at different speeds and take-off weights. The methodology of the measurement campaign was
strongly influenced by emerging guidance and has been used to calculate the directivity of sound propagation which may be of significant benefit when modelling environmental noise impacts. This paper also presents details of a listening experiment designed to investigate the subjective response
to a number of UAS operations when the listener is simulated to be either in an indoor or outdoor position. The results of the listening experiment have been analysed using linear regression analysis to understand which 'loudness' metric either conventional (LAeq, LASmax or LAE) or more specialised
loudness metrics such as Loudness (N5), Perceived Noise Level (PNL) or Effective Perceived Noise Level (EPNL) are most appropriate for estimating perceived 'loudness' and 'annoyance'. The results of this experiment indicate that both LAeq, LASmax were equally good at predicting the perceived
loudness and annoyance with an Adjusted R Squared value of 0.90 and 0.93 for loudness and annoyance respectively. Loudness metric performed marginally better with adjusted R Squared values of 0.96 and 0.90 for annoyance and loudness respectively.
Numerical Analysis of Wind Noise Transmission through BEV Underbody
Authors: Washizu Tomoya , Fukushima Tadayoshi , Hirose Kenichi , Taniguchi Keiichi , Oshima Munehiko , Miyakawa Takayuki , Enomoto Toshio
Published: June 2023

In electrified automobiles, wind noise significantly contributes to the overall noise inside the cabin. In particular, underbody airflow is a dominant noise source at low frequencies (less than 500 Hz). However, the wind noise transmission mechanism through a battery electric vehicle
(BEV) underbody is complex because the BEV has a battery under the floor panel. Although various types of underbody structures exist for BEVs, in this study, the focus was on an underbody structure with two surfaces as inputs of wind noise sources: the outer surface exposed to the external
underbody flow, such as undercover and suspension, and the floor panel, located above the undercover and battery. In this study, aero-vibro-acoustic simulations were performed to clarify the transmission mechanism of the BEV underbody wind noise. The external flow and acoustic fields were
simulated using computational fluid dynamics. The vehicle structural vibration and sound fields of the interior and exterior cabin were analyzed using vibroacoustic models consisting of three subsystems modeled by the finite-element or boundary-element method: The first is an underbody structure
finite-element model containing a white body, suspension, battery, and undercover; the second is the interior cabin space boundary-element model; the third is the exterior cabin space finite-element model for analyzing acoustic radiation resulting from vehicle structural vibration for the
small space between the floor panel and battery, the motor room and the under-vehicle space between the ground and undercover. The analysis results using the vehicle model reveal that the pressure fluctuations acting on the floor panel are more-dominant inputs for cabin noise than those acting
on the outer surface. The pressure fluctuation acting on the floor panel is affected by the acoustic mode of the space between the battery and the floor panel.