Browse Topic: Audio equipment

Items (187)

A novel framework for accelerating EDU NVH simulation using scalable transfer functions and evaluating manufacturing defects through space order excitation

2025-01-004405/05/2023

In the ultra-luxury vehicle segment, achieving optimal NVH (Noise, Vibration, and Harshness) performance across a growing range of load cases in drive and regeneration conditions presents significant engineering challenges. As the complexity of load cases escalates with varying torque ripple and transmission errors, traditional time and frequency-domain simulations become computationally inefficient. To address these challenges, an in-house software framework that employs Noise Transfer Functions (NTFs) and Vibration Transfer Functions (VTFs) is developed. The system’s dynamic response is computed once and scaled to various excitation sources, which includes radial and tangential forces derived from EMAG simulations, and gear forces derived from MBS simulation. Speed sweep simulation is performed to systematically characterize the RPM range, allowing for precise scaling of the transfer function against the original forces to obtain the responses in mounts or microphones. The resulting

Sureshkumar, Sanjai, Shaw, Stephen, Qureshi, Manucher, Duclaux de L'Estoille, Nicolas

Characterize the Sound Field Generated from a Vehicle Horn by Pellicular Analysis

2025-01-005805/05/2023

To predict the sound field produced by a vehicle horn requires a good source representation of it in the full vehicle model. This paper investigates the characterization of a physical vehicle horn by an inverse method called pellicular analysis. To implement this method, firstly an acoustic testing is performed to measure the sound pressure radiated from the horn at a certain number of microphone locations in a free field environment. Based on the geometry of a virtual horn, the locations of each microphone and measured sound pressure data, pellicular analysis is adopted to recover a set of vibration pattern of the virtual horn. The virtual horn and the recovered vibration information are then incorporated in a full vehicle numerical model to simulate its exterior sound field. The validity of this approach is confirmed by comparing the prediction for a horn in a production vehicle to the corresponding physical test which is required to meet the Brazilian regulation CONTRAN 764/2018.

Yang, Wenlong, MELO, ANDRE

Excavator exterior noise contribution analysis using angle-based operational acoustic load synthesis.

2025-01-006205/05/2023

Since earth moving machines (EMM) are subject to exterior noise (EN) regulations, OEMs need to develop mitigation solutions from an early design stage. It is challenging to predict solution effectiveness at early design stage. Excavators are distinct compared to other EMM as their upper frame rotate while keeping lower frame fixed. ISO 6395(2) or EC/2000/14(1) require EMMs to follow specific operating maneuvers where noise sources change their position, directivity, and speed along the operating cycle. These conditions pose challenges in performing noise contribution analysis as a function of angular position and operating condition. Authors successfully demonstrated Acoustic source quantification and contribution analysis for linearly moving EMMs. However, excavator pose data processing challenges due to angular motion. This work demonstrates the use of frequency domain ASQ for operational acoustic source quantification and use of frequency domain virtual prototype sub structuring

Vesikar, Prasad Balkrishna, Haynes, Timothy, Aquino Arriaga, Adrian Antonio, Drabison II, John, Chaduvula, Prasanna

Comprehensive EV Sound Design project from Marketing Requirements to Series

2025-01-001805/05/2023

This paper presents the results of a project to design new comprehensive sound sets for several electric vehicle models having each specific branding expectations. This was achieved thanks to a close collaboration between one major Chinese electric vehicle manufacturer and an acoustic software provider, relying on shared experience, knowledge, and tools to meet the initial requirements set. Firstly, a scenarized journey and brand-related symbolism were defined and served as a basis for creating meaningful sketches of sound design in a cross-team effort (designers, NVH, production, audio system, etc.). Various sound functions were considered for exterior sounds, such as AVAS, and interior sounds, such as ambiance, HMI, and alarms. A special care was dedicated to the so-called Active Sound Design aiming at providing speed and acceleration feedback to the driver, in the absence of a clearly audible engine noise. A listening test was then conducted in order to assess how the proposed

LI, Yanhao, Minard, Antoine, Boussard, Patrick, Zhang, Charles

Active Control of Engine Order Noise for Heavy-duty Trucks: Using the Genetic Algorithm for the Optimization of Error Microphone Arrangement

2025-01-001305/05/2023

The arrangement of error microphones for a vehicle active noise control (ANC) system is no trivial work, especially for heavy-duty trucks due to the dilemma resulted from the large volume of the cab and the limited number of microphones accepted by most manufacturers in the auto industry. Most ANC developers resort to trial and error, which is not only a heavy workload given the amount of interested working conditions to be test, but also does not guarantee to yield the optimum noise cancellation performance. In this paper, the authors proposed an error microphone selection methodology using a genetic-algorithm (GA) -based mechanism. The target vehicle was a heavy-duty truck with a six-piston diesel engine, and two scenarios were particularly interested, i.e. driver & copilot and driver & one passenger sleeping on the berth. We first arranged eight microphones at different locations in the cab, five on the headrests, two on the B pillars and one at the head position of the sleeping

Wang PhD, Jian, Ling, Zihong, Zhang, Zhe, Cai, DeHua, lv, Xiao, Zhang, Ming, Gao, GuoRan

Active noise control with head tracking system

2025-01-001205/05/2023

In active noise control, the control region size(zone of control) decreases as the frequency increases, so that even a small moving of the passenger's head causes the ear position to go out of the control region. In order to increase the size of the control region, many speakers and microphones are generally required, but it is difficult to apply it in a vehicle cabin due to space and cost constraints. In this study, we propose moving zone of quite actvie noise control technique. An 2D images based head tracking system captured by a camera to generate the passenger's head coordinates in real time with deep learning algorithm. In the controller, the control position is moved to the ear position using a multi-point virtual microphone algorithm according to the generated ear position. After that, the multi-point adaptive filter training system applies the optimal control filter to the current position and maintains the control performance. Through this study, it is possible to secure the

Oh, ChiSung

A Study on the Subwoofer Rattle Noise Analysis and System Target Setting

2025-01-009005/05/2023

Rattle noise from electrical sound systems is becoming one of the prominent issues for automakers as it directly affects the perception of customers about vehicle quality. Recent times, quality sound system is prerequisite for automotive passenger vehicles. And, in the whole sound systems subwoofer forms dominant part of sound output. However, sub-woofer rattle noise problem sometimes occurs in small and midsize SUV. Generally, sub woofers are located inside rear quarter area (back side of the quarter panel), due to the limitation in the available space. Mainly rattle is noise resulting from physical impact of two parts due to vibrations when relative displacement is bigger than gap of two parts, it occurred in 50-100Hz, which is main excitation range of sub-woofer. In this study, we analyze the sub-woofer structural vibration analysis for five sample vehicles based on the test and correlation. However, the present sub-woofer system model has limitation in determining the level of this

Thota, Jagadeesh, Choi, Seungchan, Park, Jong-Suh

Localisation of Ultra-short Sound Emissions from Automotive Components by Using the Sound Field Scanning Method

2025-01-009205/05/2023

Design verification and quality control of automotive components require the analysis of the source location of ultra-short sound events, for instance the engaging event of an electromechanical clutch or the clicking noise of the aluminium frame of a passenger car seat under vibration. State-of-the-art acoustic cameras allow for a frame rate of about 100 acoustic images per second. Considering that most of the sound events introduced above can be far less than 10ms, an acoustic image generated at this rate resembles an hard-to-interpret overlay of multiple sources on the structure under test along with reflections from the surrounding test environment. This contribution introduces a novel method for visualizing impulse-like sound emissions from automotive components at 10x the frame rate of traditional acoustic cameras. A time resolution of less than 1ms eventually allows for the true localization of the initial and subsequent sound events as well as a clear separation of direct from

Rittenschober, Thomas

Method for Performing Indirect Lightning Test Simulation

2022-26-118205/26/2022

From the statistics it has been observed that major qualification test failures in aerospace system are from lightning tests. These failures lead to major cost and schedule implications as fixing these issues later in the design usually requires a product re-spin. To avoid such failures, testing of critical interfaces using simulation allows engineers to investigate the behavior of the product/system in different scenarios and visualize the effect of these changes at an earlier stage in the design. Achieving this through simulation also eliminates the need of heavy costs associated with physical prototyping & testing. The existing simulation techniques use prebuilt & formula-based lightning waveform models and also do not take into consideration the end to end impedance characteristics like cable impedance, remote impedance, etc. With these available techniques, achieving results closer to practical scenarios is difficult. To overcome some of these challenges, this paper presents a

Rajeurs, Ajaypal, Gouda, Vidyadhar

Cost-Effective Day & Night Marking Using Lasers

TBMG-3862803/01/2021

“Day & night marking” is used in automobiles, aviation, instrumentation and computer keyboards to make buttons and controls (e.g. door locks, window controls, sound system adjustments, etc.) clearly visible under ambient illumination conditions varying from bright sunlight (day) to low light (night). Although it sounds simple, manufacturing these products cost-effectively in a small-batch production environment requires the use of a sophisticated, automated, laser-based tool.

Wiegand Wire: Energy Harvesting and More

TBMG-3738708/01/2020

The “Wiegand effect” was discovered more than 40 years ago and while it has been used successfully in several specialized applications, its full potential for energy harvesting and signal generation has received only limited recognition. With enhancements to the energy output from Wiegand devices and the emergence of a new generation of ultra-efficient electronic chips, the technology is showing significant promise, especially in the exciting area of the Industrial Internet of Things (IIoT).

3D Audio Reproduction via Headrest equipped with Loudspeakers – Investigations on Acoustical Design Criteria

2020-01-156706/03/2020

This paper focuses on the analysis and evaluation of acoustical design criteria to produce a plausible 3D sound field solely via headrest with integrated loudspeakers at the driver/passenger seats in the car cabin. Existing audio systems in cars utilize several distributed loudspeakers to support passengers with sound. Such configurations suffer from individual 3D audio information at each position. Therefore, we present a convincing minimal setup focusing sound solely at the passenger’s ears. The design itself plays a critical role for the optimal reproduction and control of a sound field for a specific 3D audio application. Moreover, the design facilitates the 3D audio reproduction of common channel-based, scene-based, and object-based audio formats. In addition, 3D audio reproduction enables to represent warnings regarding monitoring of the vehicle status (e.g.: seat belts, direction indicator, open doors, luggage compartment) in spatial accordance. Furthermore, individual sound

Brandner, Manuel, Hatheier, Thomas, Sontacchi, Alois

Reinforcement of Low-Frequency Sound by Using a Panel Speaker Attached to the Roof Panel of a Passenger Car

2020-01-157006/03/2020

The woofer in a car should be large to cover the low frequencies, so it is heavy and needs an ample space to be installed in a passenger car. The geometry of the woofer should conform to the limited available space and layout in general. In many cases, the passengers feel that the low-frequency contents are not satisfactory although the speaker specification covers the low frequencies. In this work, a thin panel is installed between the roof liner and the roof panel, and it is used as the woofer. The vibration field is controlled by many small actuators to create the speaker and baffle zones to avoid the sound distortion due to the modal interaction. The generation of speaker and baffle zones follows the inverse vibro-acoustic rendering technique. In the actual implementation, a thin acrylic plate of 0.53ⅹ0.2 m2 is used as the radiator panel, and the control actuator array is composed of 16 moving-coil actuators. The shape of the desired speaker zone is an ellipse, and the required

Lee, Ki-Ho, Cho, Munhwan, Ih, Jeong-Guon

5 Ws of PAWS Smart Headphones

TBMG-3619903/01/2020

Pedestrians who wear headphones or earbuds to listen to music, text, or talk on smartphones while walking, putting themselves at risk by tuning out the traffic around them.

5 Ws of EarEcho

TBMG-3569312/01/2019

Anyone who uses a smartphone with in-ear earphones.

Ultra-Thin Capacitive Sensor Has the Least Possible Resistance to Motion

TBMG-3246808/01/2018

A thin and flexible sensor was developed for sensing sounds, since it can move with the airflow made by even the softest noises. With the least possible resistance to motion, the sensor addresses issues with accelerometers, microphones, and many other similar sensors. The goal was to create a sensor that only resists gravity. It needs to stay connected to the device, but otherwise needed to move with even the slightest sounds or air movement. Being able to move with the air is how sensors are able to tell when a sound is present and from which direction it is coming.

Sound Inaudible to Humans Can Be Recorded by Microphones

TBMG-2870204/01/2018

Microphones, from those in smartphones to hearing aids, are built specifically to hear the human voice — humans can’t hear at levels higher than 20 kHz, and microphones max out at around 24 kHz, meaning that microphones only capture the sound humans hear.

Paper-Thin Device Acts as a Loudspeaker and Microphone

TBMG-2802612/01/2017

A paper-thin, flexible device was created that can generate energy from human motion, and can act as a loudspeaker and microphone. The transducer is ultrathin, flexible, scalable, and bidirectional, meaning it can convert mechanical energy to electrical energy, and vice-versa.

PLCs Improve Control of Radio Broadcasts

TBMG-2643502/01/2017

Broadcasting employs the latest technology in many areas, but controlling the broadcast hardware connected to the antenna and the related transmission power, source, and facilities is usually still a low-tech operation. Typically, a broadcast engineer will drive to the unattended transmitter, translator, or repeater site to flip switches and make other manual adjustments (Figure 1).

Source Separations and Identification by Structural Holography

2016-01-179906/15/2016

The source field reconstruction aims at identifying the excitation field measuring the response of the system. In Near-field Acoustic Holography, the response of the system (the radiated acoustic pressure) is measured on a hologram using a microphones array and the source field (the acoustic velocity field) is reconstructed with a back-propagation technique performed in the wave number domain. The objective of the present works is to use such a technique to reconstruct displacement field on the whole surface of a plate by measuring vibrations on a one-dimensional holograms. This task is much more difficult in the vibratory domain because of the complexity of the equation of motion of the structure. The method presented here and called "Structural Holography" is particularly interesting when a direct measurement of the velocity field is not possible. Moreover, Structural Holography decreases the number of measurements required to reconstruct the displacement field of the entire plate

Thomas, Jean-Hugh, Chesnais, Corentin, Totaro, Nicolas, Guyader, Jean-Louis

CES rollouts extend connectivity, app integration

16AUTP02_0402/01/2016

The tightening links between autos and consumer electronics were in evidence at the 2016 Consumer Electronics Show in Las Vegas as several automakers and suppliers unveiled infotainment technologies. Connectivity and simplified app integration technologies were among the many transportation offerings at the monstrous show. Vendors throughout the industry unveiled connectivity products. An amplifier was among Harman's connectivity offerings. It uses a customized microcontroller to provide connectivity, noise cancellation, equalization, and surround sound. That trims size and complexity significantly.

Costlow, Terry

SAE U.K. SECTION CO-HOSTS LECTURE SERIES ‘STARRING’ NASA ENGINEER/ EXPERT

16MOMP02_0402/01/2016

Dr. Ravi Margasahayam of NASA is the engineer responsible for ensuring payload safety for the Space Shuttle and the International Space Station. The SAE United Kingdom Section recently collaborated with the Institution of Mechanical Engineers (IMechE) and the Institution of Engineering and Technology (IET) in the U.K. to arrange an extended lecture series by Dr. Ravi Margasahayam of NASA. He is the engineer responsible for ensuring payload safety for the Space Shuttle and the International Space Station (ISS). He has a background in acoustics and vibration, and has been with NASA for 25 years. Margasahayam provides talks on NASA activities internationally, something that Professor Bernard Challen (an SAE volunteer who lives in the U.K. and is active in various SAE meetings) discovered last June in Madison Wisc., when he heard him speak. What started as an intention to set up maybe three lectures in the U.K. developed into a series of nine meetings. By coincidence, the lecture tour

MARK 4 SELECTIVE CALLING (SELCAL)

ARINC714A (Current)11/04/2015

This document represents a significant improvement to existing Selective Calling (SELCAL) standards used with HF and VHF voice communications. The goal is to eliminate the possibility that two or more aircraft could respond to the same radio call. The Mark 4 SELCAL system definition provides the following: " Guidance for integrated and federated audio systems " 32 audio tones total (16+16) yielding up to 215,760 unique codes " SELCAL form, fit, & function definition " Interwiring and installation details " Defines SELCAL decoding requirements in the presence of significant signal degradation.

Airlines Electronic Engineering Committee

Sensing Device Separates Simultaneous Sounds

TBMG-2278008/19/2015

A new technology developed at Duke University uses metamaterials and compressive sensing to determine the direction of a sound and extract it from the surrounding background noise. Once miniaturized, the device could have applications in hearing aids, cochlear implants, and ultrasound medical sensors.

Quantifying Hands-Free Call Quality in an Automobile

2015-01-233506/15/2015

Hands-free phone use is the most utilized use case for vehicles equipped with infotainment systems with external microphones that support connection to phones and implement speech recognition. Critically then, achieving hands-free phone call quality in a vehicle is problematic due to the extremely noisy nature of the vehicle environment. Noise generated by wind, mechanical and structural, tire to road, passengers, engine/exhaust, HVAC air pressure and flow are all significant contributors and sources of noise. Other factors influencing the quality of the phone call include microphone placement, cabin acoustics, seat position of the talker, noise reduction of the hands-free system, etc. This paper describes the work done to develop procedures and metrics to quantify the effects that influence the hands-free phone call quality. It will be shown that a listening study of using 49 evaluators, indicated that the ETSI EG 202 396-3EG (VoIP Standard) for SMOS (Speech Mean Opinion Score) and

Amman, Scott, Charette, Francois, Nicastri, Paul, Huber, John, Richardson, Brigitte, Puskorius, Gint, Gur, Yuksel, Cooprider, Anthony

Improving Tube Sound Transmission Loss Measurements Using the Transfer Matrix Technique to Remove the Effect of Area Changes

2015-01-231006/15/2015

The Sound Transmission Loss of automotive intake and exhaust components is commonly measured using the four microphone tube method per ASTM E2611 [1]. Often area adapters are used to match the component diameter to that of the tube apparatus. These area adapters affect the Sound Transmission Loss measurement, especially at very low frequencies. The use of the Transfer Matrix Technique to remove the effect of the area adapters is described. The improvements for step and cone area adapters are compared.

Green, Edward Ray

Magnetic Fluids Deliver Better Speaker Sound Quality

TBMG-2178504/01/2015

In the early 1960s, NASA scientists were trying to move fuel into an engine without the benefit of gravity. A scientist at Lewis Research Center (now Glenn Research Center) came up with the idea to magnetize the liquid with extremely fine particles of iron oxide. That way, fuel could be drawn into the engine using magnetic force.

Microphones and Accelerometer Sensors Network for Acoustic Diagnostics (MASNAD)

TBMG-2176204/01/2015

A system has been developed using sound to detect problems on rovers or other remote platforms autonomously. It consists of a sensor array of microphones and accelerometers that uses the differences in the sounds generated by the motors, gears, instruments, or other devices being monitored to determine abnormal operation conditions.

“Ascent - Commemorating Shuttle” — A NASA Film and Multimedia Project DVD

TBMG-1992206/01/2014

NASA seeks to preserve, and make readily accessible, historical Space Shuttle launch footage to inspire and educate NASA stakeholders both in and outside the NASA family through the dissemination of the Ascent production materials as a DVD, and through both NASA Television and online social media avenues without incurring distribution and media costs.

Sample-Rate Conversion for Non-Clocked Audio Sources

2014-01-026104/01/2014

In a connected vehicle, digital audio content may arrive at the audio system from sources that provide packets of audio samples with no associated sample clock. A common example is streamed internet audio. To process and play these sources, the audio system must first convert the audio stream so that it is compatible with the system's sample clock. Traditional sample-rate conversion methods are typically not capable of doing this. This paper presents and compares approaches for performing the conversion.

Whikehart, Bill

Software Defined Radio Enables Flexible Communications for NASA

TBMG-1982402/01/2014

Communication is key to just about any endeavor. NASA’s ability to update and modify communication capabilities to reflect the latest upgrades without impacts to mission time or a trip back to Earth ensures optimal communication continues. In-orbit reconfiguration for spacecraft radios and systems, including those on the International Space Station, is the goal behind NASA’s Space Communications and Navigation (SCaN) Testbed.

Investigating GSM Interference in Automotive Sound Systems Using State of the Art Electromagnetic Simulation

2013-36-019810/07/2013

EMI (Electromagnetic Interference) is one of the major concerns today in the automotive industry. The main reason is that vehicles are using and depending more on electronic technology. The causes of electromagnetic interference problems are not only related to the ever-increasing number of embedded electronics systems in vehicles, but also to external electronic devices that are brought in to automobiles by drivers and passengers (e.g. cell phone, MP3 players, Bluetooth devices, portable video games). Even though these problems can cause serious issues on safety systems like the airbag, their symptoms are often noticed in a less harm way in the sound system. A very common EMI problem in automotive sound systems is a particular noise caused by devices that uses GSM (Global System for Mobile Communications) technology. Most of the cell phones and vehicle locators rely on GSM technology. In Brazil there is a national normative known as Contran 245, which when issued, will enforce the use

Mologni, Juliano F., Siqueira, Cesareo L. R., Nogueira, Artur, Colin, Arnaud, Alves, Marco A. R., Kopp, Markus

Spherical Beamforming with Enhanced Dynamic Range

2013-01-197705/13/2013

Beamforming with an array of microphones on a sphere is an attractive tool for doing noise source localization in cabin environments. In order to achieve acceptable angular resolution, the array must have some minimum diameter, implying that many microphones are needed to obtain low sidelobe level over the frequency range of interest. For electric cars there is an increased need to cover high frequencies. The present paper describes a method to significantly reduce the sidelobe level over a broad frequency range relative to Spherical Harmonics Beamforming (SHB). For each focus point, a set of Finite Impulse Response (FIR) filters are optimized to minimize the highest sidelobe in a Filter And Sum (FAS) beamformer, while maintaining sensitivity at the focus point and limiting the White Noise Gain (WNG). Similar approaches have been published, but a main issue in connection with applications for noise source mapping is the computational load in performing the optimization of FIR filters

Hald, Jorgen

Restoring and Upgrading of a Ford Motor Company Reverberation Room Test Suite

2013-01-196005/13/2013

This paper presents the upgrades and improvements needed to bring an old and seldom used reverberation room test suite up to current standards. The upgrades and improvements included eliminating a below-floor pit that was open to the reverberation room, improving the acoustical diffusion within the room, enlarging the opening between the reverberation room and an adjacent anechoic chamber, renovating the anechoic receiving chamber, constructing an innovative sound transmission loss test fixture, and installing of a high power reverberation room sound system.

Kolano, Richard, Abhyankar, Sanjay, Martin, Thomas

Assessment of Automatic Volume Leveling for Automotive Sound Systems

2013-01-016204/08/2013

This paper presents an assessment of competing algorithms for normalizing volume levels between tracks and/or sources in an automotive infotainment system. Portable media players such as smartphones and iPod® devices are extremely popular for listening to music collections or streaming content from the Internet. The lack of normalization is a source of dissatisfaction if the user experiences significant changes in audio level between tracks. Several commercially available algorithms exist to solve this problem. This research includes a double-blind listening test comparing an audio sample processed with the different leveling algorithms to an unprocessed reference. The listener preference rating is recorded and results indicate which algorithm is preferred.

Cadena, Robert, Dakroub, Husein

New Approaches for Low Voltage Audio System and Circuit Design

2012-01-003704/16/2012

New vehicle systems that stop and restart the engine to avoid prolonged idling place new requirements on audio systems. In particular, there is a need for the audio system to continue to operate during the engine start sequence. In the past this was not an issue, as audio systems could be turned off during the engine start sequence. Among the ramifications for this “operate while starting” requirement is that the audio system must operate at a lower voltage, say 6 volts, instead of 10 volts. Audio system operation in this context means continuing to play music without interruption or spurious noises. The main focus of this presentation is on audio circuits, both line-level and speaker level. In the past, line level outputs could be fed by linear regulated power supplies that developed 8 to 10 volts. The signal levels sent from one module to another could thus be in the 3 volt RMS range. Given DSP integrated circuits with 3.3 or 5 volt power supplies, it was often necessary to “gain up

Tillo, Joe, Tressler, Steve, Hanson, Jonathan

The New EMC Challenges to Design Vehicle with Consumer Electronics Devices

2011-36-034710/04/2011

The last ten years have experienced a massive integration of consumer electronics devices in vehicles such as mobile phones, audio and video players, USB devices, and internet access capability. Consumers are now demanding the integration of portable and home devices to vehicle systems transforming it to an extension of the home and office thus providing entertainment and connectivity to both short and long trips The integration of devices that were not designed or specified to operate in the vehicle environment has imposed challenges to the engineers designing vehicle electronics systems in particular to the EMC engineers. The need to design the subsystems that are completely integrated with the consumer electronics devices and also compliant with the car makers current specifications has proven to be a major issue due to the fact that one of the components, the consumer electronic devices, cannot be controlled. Making the design process extremely complex and in many cases leading to

de Miranda, Ary Pontes, Filho, Sebastiao Balani, Brasil, Rafael Brandao

Measurement Dynamic Range Considerations for Sound Transmission Loss Testing

2011-01-165005/17/2011

Highly effective double-wall systems for automotive applications can often have over a 90 dB span in sound transmission loss values between low frequencies, where they are usually least effective and upper frequencies, where they are typically most effective. Particularly for 16-bit measurement systems, but even for 24-bit systems, this can represent a very difficult scenario for measurements in either the source and/or receiving chamber(s). A methodology to balance the observed dynamic ranges in both source and receiving chambers is presented and discussed in this paper. An improved sound transmission loss measurement system can therefore be implemented which reduces the potential of overload or noise floor contamination occurring in measurements within either chamber. Low frequency SPL requirements for the source chamber speaker system and flanking noise issues with adjacent test chambers can also be typically reduced. Although this paper focuses on the case of SAE J1400 [1] sound

Dinsmore, Michael

An Objective Methodology for Measuring Earmuff Hearing Protector Noise Attenuation

2010-36-050210/17/2010

This article describes an objective methodology for measuring the noise attenuation of earmuff hearing protectors using as a reference the method known as microphone-in-real-ear (MIRE). The methodology implements the Insertion Loss (IL) paradigm, in which IL is measured using miniature microphones, specially designed to comply with ANSI and ISO standards for the MIRE technique. The results for a commercial hearing protector are compared with the subjective method known as real-ear-attenuation-at-threshold (REAT). Correction factors are included in the methodology to account for external effects such as physiological noise and bone conduction. The objective method predicted well the real protection of the earmuff and the proposed methodology showed lower standard deviation values than the REAT method.

de Almeida Agurto, Danilo, Gerges, Samir N. Y., Arenas, Jorge P.

The Implementation of Time Selective Technique for Simulated Free-Field Measurements to Loudspeaker Characterization

2010-36-050810/17/2010

The use of time selective techniques has been used for years in signal processing for acoustic, vibration and electro-acoustic to make simulated free-field measurements. Many acoustic solutions have been implemented and developed by specialized software companies and are offered to final users by the costs of large amounts of money. However, recent advances in hardware, software and data acquisition systems - allied to a good background in signal processing - has enabled the implementation of fast and practical solutions to more complex problems involving direct signal manipulations, analysis and post-processing. This work presents the home implementation of a test-bench solution used for loudspeaker quality evaluation that uses time selective techniques enabling measurement of free field response of loudspeakers to be performed without the need of an anechoic chamber, allowing the conduction of the measurement in a low cost test bench, inside an ordinary quiet room, without spent

Ferraz, Fabio G., Castro, Marco, Sczibor, Valdinei, Medeiros, Juliano, Faria, Leonardo

Sound Field Visualization using Spherical Holography

2010-01-142006/09/2010

Beamforming based on measurements with a spherical microphone array is a recognized technique for localization of noise sources. The method is very efficient for getting a quick overview of the positions of the most dominant sources. However, when more detailed information about the radiation from a source is needed, acoustical holography is normally more suitable, because it provides the actual acoustical quantities (pressure, velocity and/or intensity) at positions on or near the source surface, whereas beamforming only gives a directional map of contribution at the array position. Even though spherical arrays are most often used for beamforming they can also be applied for holography purposes. This means that with the same hardware beamforming can be used to identify a noise source, and then the array can be moved closer to the source to get a clearer picture of the radiation by using holography. Also, beamforming has a poor directional resolution at low frequencies, whereas

Gomes, Jesper, Haddad, Karim, Hald, Jorgen

Most Common Autosound Quality Errors

2010-01-115404/12/2010

Tom Nousaine has tested over a thousand OEM and aftermarket car sound systems over the past 20 years for Car Stereo Review, Mobile Entertainment, Road Gear, DLC Design and his current business Listening Technology. He discloses the most common sound quality errors found in automotive audio systems in terms of tonal balance, spatial and dynamic attributes. Tom has also tested hundreds of home and professional loudspeaker systems for publications like Audio, Stereo Review, Sound & Vision and Pro Audio Review.

Nousaine, Tom

Measuring Imaging - A New Tool for Tuning Audio Systems

2010-01-115204/12/2010

Automotive audio systems require signal processing to address losses of spatial rendition of stereo and multichannel sources due to off-centerline listening and the proximity of cabin walls where the speakers are located. The digital signal processing is optimized for each vehicle type and audio option by skilled tuning engineers. They spend the majority of their tuning time on spatial issues when preparing a vehicle. One reason for this is that, until now, there has been no measurement of imaging performance. Engineers have relied on the indirect measures of arrival delay, spectrum and their own hearing to balance the several speakers likely to be contributing to perceived direction, distance and ambience. This paper describes a new module for a measurement system widely used in automotive audio. In addition to assisting the tuning engineer, the system documents audio performance in Tonal Balance, Maximum Output, Distortion, and now, Spatial Rendition.

Clark, David L.

Integrated Spacesuit Audio System Enhances Speech Quality and Reduces Noise

TBMG-586711/01/2009

A new approach has been proposed for increasing astronaut comfort and speech capture. Currently, the special design of a spacesuit forms an extreme acoustic environment making it difficult to capture clear speech without compromising comfort. The current system, called Communication-Cap-based Audio (CCA), relies on a single microphone placed close to the subject’s mouth. While this results in clear audio, it also has problems: wire fatigue, blind mating, interference with food/drink, need for custom communication caps, and not being able to adjust the microphone during extravehicular activities.

Understanding Complex-Domain, Floating-Point DSPs

TBMG-3504909/01/2009

Every day we use complex mathematics, hidden inside products. When we listen to a song from an MP3 player, we are using the Fast Fourier Transform (FFT), a “complex domain” algorithm. The best car and home entertainment system amplifiers have at least one Digital Signal Processor (DSP) performing complex math. Hands-free telephones have DSPs to perform acoustic echo canceling and background noise reduction using complex math.

Measurement Accuracy for Qualification Testing of Anechoic and Hemi Anechoic Chambers Using the Continuous Draw Method

2009-01-215105/19/2009

Anechoic/hemi-anechoic chamber qualification testing is typically conducted by measuring the free-field response as a microphone is traversed away from a central noise source toward the chamber perimeter. Based on ISO standard 3745, the microphone can be moved either incrementally or continuously. If using broad band random noise, the measurement must last a sufficient period of time to ensure an accurate averaged level is recorded. For low frequencies this can require extended periods of time. Attempting to establish a microphone traverse rate slow enough to allow sufficient time averaging becomes tedious. Over distances of 3 meters, this can require a draw that takes 20 minutes or longer. This paper discusses techniques explored to produce results that are quicker and more accurate than by typically applied methods.

Brown, Darren J.

“Targeting Consumer Needs in the Perfect Storm: Changing the Automotive Lifestyle”

2008-21-003810/20/2008

The intersection of changing lifestyles and evolving transportation needs finds smart USA well positioned for launch in 2008 during one of the most competitive periods in U.S. automotive history. In a zero sum market with new global entrants competing for single points of share, where quality levels have been redefined and fractions of points separate the best from the challengers, lifestyle awareness, innovation and product positioning become the differentiators. Simply adding features has left some with hefty investments and confused consumers. Bigger is not always better. More is not always desirable. The real opportunity for new entrants to the US market may be defined within niche markets where changing lifestyles allow for the emergence of new segments. Today, smart USA has surfaced as a clear example of right product, right place, right time. This paper will explore 1) historical factors of OEM market differentiation, 2) emerging changes in consumer habits and life styles in the

Pergament, Douglas S.

Understanding Consumer Needs: The Enduring Legacy of Konosuke Matsushita

2008-21-003710/20/2008

Ninety years ago, in 1918, Konosuke Matsushita founded a company, which is now widely known as Panasonic, with three simple principles in mind. First, he wanted to create products that would permit average people i.e., consumers, to benefit from the most exciting emerging technology and infrastructure advance of his time, i.e., electric power. Second, he wanted to create products that average consumers could afford. And finally, he knew that his success would be directly related to his ability to create products that add value to the lives of those who purchased them – products that address consumer needs and desires. These simple, yet fundamental principles formed the foundation upon which one of the world's most far reaching and influential enterprises was born, and upon which its operation still is based today. Starting with Konosuke Matsushita's first products -simple light sockets and bicycle lights - to today's high tech wonders – 32 GB SD Memory Cards, Blu-ray, and High

Liao, Paul

Challenges for Infotainment Expansion in Automotive Market

2008-36-030310/07/2008

The automotive market is absorbing many technological innovations into its products. Mobile phones, pen drives, iPods, memory sticks and other electronic equipment and portable devices that provide entertainment and connectivity are dominating new vehicle features. Infotainment expansion in the automotive market is facing new challenges to provide usability and comfort to customers inside cars. The storage of digital files and its application into new cars is the major issue; besides, the offering of entertainment, navigation, telemetry and connectivity to customers exceeds the current vehicle's electrical structure designed by OEM's engineering. This article evaluates the current vehicle infotainment scenario, as well as the alternatives and new trends that may be applied to the automotive market in the next product generations.

de Carvalho, Fabrício Braga Soares

Consumed by changes

AUTOOCT08_0110/01/2008

Reprogramming becomes the focus of engineers as radios become multifunction head units integrating many infotainment functions. The term “infotainment” has become a popular buzzword, one that translates to either headache or opportunity for many engineers. Radios are being transformed into head units that handle almost any data that drivers or passengers want to access. The change is dramatic, changing radios from comparatively simple hardware-based systems to advanced computers that can adapt to the rapid changes of the consumer-electronics industry Coping with this tight integration between cars and portable electronics means adopting the technologies of these consumer products.

Costlow, Terry

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