Helen Ule

Comparative study of a low frequency emergency siren to traditional siren technology

This study measures and compares the acoustic characteristics of a traditional electronic emergency siren and an innovative low frequency Rumbler siren technology. The Rumbler siren’s low frequency emissions can travel further and have a greater ability to penetrate and induce structure-bone excitation in nearby vehicle cabins compared to other siren technology. The result is a better ability to warn both nearby vehicles and pedestrians thus lessening the potential of emergency vehicle collisions. The siren technologies were evaluated using three measurement scenarios to determine acoustic localization characteristics, drive-by effectiveness, and the ability to overcome the problem shadowing phenomenon typical at congested intersections. A comparative analysis of the acoustical characteristics of the standalone siren and the addition of The Rumbler system provided insight in regards to the relative effectiveness of each siren mode. The siren system equipped with The Rumbler technology gave a noticeable in...

Study of acoustic localization of an emergency siren

Having the ability to adequately detect the direction of an approaching emergency siren is critical to the effectiveness of the emergency system. Having this ability allows both pedestrians and drivers of nearby vehicles to more quickly and safely react to an approaching emergency vehicle. This study considers a typical electronic siren system that is currently being used by the Windsor Fire & Rescue Services Department. This siren has two fundamental settings: the standard siren signal and the air horn mode, which is typically used when the emergency vehicle is approaching roadway intersections, as these pose the most danger to occupants of both emergency vehicle and general public. Siren and air horn signals were recorded at specific distances from the driver’s position at 45° radial increments. From these, the recorded signals and sound pressure levels measured inside the cabin of the vehicle at the various approach angles were used to prepare a subjective jury evaluation to determine the localization ...

Study of a low frequency emergency siren in comparison to traditional siren technology

This study measures and compares the acoustic characteristics of a traditional electronic emergency siren and an innovative low frequency Rumbler siren technology. The Rumbler siren’s low frequency emissions can travel further and have a greater ability to penetrate and induce structure-bone excitation in nearby vehicle cabins compared to other siren technology. The result is a better ability to warn both nearby vehicles and pedestrians thus lessening the potential of emergency vehicle collisions. The siren technologies were evaluated using three measurement scenarios to determine acoustic localization characteristics, drive-by effectiveness and the ability to overcome the problem shadowing phenomenon typical at congested intersections. A comparative analysis of the acoustical characteristics of the standalone siren and the addition of The Rumbler system provided insight in regard to the relative effectiveness of each siren mode. The siren system equipped with The Rumbler technology gave a noticeable increase in sound pressure level for each of the three test scenarios. Through analysis of the measured data the overall performance of the emergency siren system with the Rumbler technology was shown to be a more effective emergency notification device compared to the standalone electronic siren.This study measures and compares the acoustic characteristics of a traditional electronic emergency siren and an innovative low frequency Rumbler siren technology. The Rumbler siren’s low frequency emissions can travel further and have a greater ability to penetrate and induce structure-bone excitation in nearby vehicle cabins compared to other siren technology. The result is a better ability to warn both nearby vehicles and pedestrians thus lessening the potential of emergency vehicle collisions. The siren technologies were evaluated using three measurement scenarios to determine acoustic localization characteristics, drive-by effectiveness and the ability to overcome the problem shadowing phenomenon typical at congested intersections. A comparative analysis of the acoustical characteristics of the standalone siren and the addition of The Rumbler system provided insight in regard to the relative effectiveness of each siren mode. The siren system equipped with The Rumbler technology gave a noticeable incr...

Acoustic localization of an electronic emergency siren

Having the ability to adequately detect the direction of an approaching emergency siren is critical to the effectiveness of the emergency system. Having this ability allows both pedestrians and drivers of nearby vehicles to more quickly and safely react to an approaching emergency vehicle. This study considers a typical electronic siren system that is currently being used by the Windsor Fire & Rescue Services Department. This siren has two fundamental settings; the standard siren signal and the air horn mode, which is typically used when the emergency vehicle is approaching roadway intersections, as these pose the most danger to occupants of both emergency vehicle and general public. Siren and air horn signals were recorded at specific distances from the drivers position at 45° radial increments. From these, the recorded signals and sound pressure levels measured inside the cabin of the vehicle at the various approach angles was used to prepare a subjective jury evaluation to determine the localization c...

Validating a binaural head for use in jury testing

A test procedure for use in loudness perception tests must be created to completely describes a phenomenon while at the same time minimizing jury listening fatigue. One contributor to this fatigue is the amount of time necessary for the test subject to experience all the required signals. Head and torso simulators have been used for years as a means to reliably quantify the acoustic performance of a product while avoiding the influence of listener bias and fatigue. This procedure not only controls the test parameters but also removes any human error that may occur. The purpose of this investigation is to qualify a head and torso simulator for use in loudness investigations. The objective of this experiment is to correlate the results from using this equipment to human subject results for high resolution experiments on directionality of loudness.

Comparative study of unsteady loudness models for mechanical and real sounds

While noise levels are most often quantified using physical quantities including A-weighted sound pressure level, these metrics do not adequately represent the human perception of the noise. For this, loudness is a more appropriate acoustic metric as it describes the perceived acoustic intensity of a sound. Given that real sounds are often unsteady, a most useful loudness calculation will also account for the perceptional phenomena of time and temporal masking. Studies have been done which demonstrate the performance of several loudness models for pure tone sounds and compare these results to the ISO 226 equal loudness curves. This investigation goes beyond that and evaluates the performance of two unsteady loudness models, the Glasberg and Moore model and the DIN 45631-A1 method, using mechanical and real life sounds. Through implementation ofa jury, the differences of the two loudness calculation methods are demonstrated by plotting the perceived loudness of the sounds for two different levels compared ...

A-weighting the equal loudness contours

The standardized equal loudness contours identify the non-linearities of the human auditory system using simple sinusoidal input signals. The graphical illustration of auditory performance trends provides a visual representation of these non-linearities with respect to both frequency and amplitude across the range of auditory perception. Metrics such as the A-Weighting filter approximate one generalized curve shape, in an effort to quantify measured values in a manner that represents the perception of the measured sound. With the release of the ISO226:2003 version of the standard, the most recent version of the equal loudness contours provide an improved contour set with more refined shapes and steeper slopes. The purpose of this study is to investigate the performance of the A-weighting function compared to the updated curves of the equal loudness contours. Included is an examination and discussion of the appropriateness of the continued use of the existing A-Weighting filter. Given the overall un-hyperb...

Proposed hybrid multiple look approach for calculating unsteady loudness

Experimental studies have shown that for short gaps between 2 to 5 ms, the perceived loudness is higher than for uninterrupted noise presented to the ear. Other studies have also shown that the present temporal integration models for the calculation of time varying loudness do not adequately account for short duration phenomena. It has been proposed that the multiple look approach is a more applicable method for describing these short term circumstances. This approach breaks a sound into very small durations which allows for the intelligent processing of the looks and decision making depending on the nature of the stimulus. However, present technologies, such as the Fast Fourier Transform, are not adequate to deal with short duration sounds across the entire frequency spectra. A compromised approach using a proposed hybrid model is presented to account for perceived loudness levels for sounds in the presence of gaps while using an integration model. This hybrid multiple look model was tested using several...

Comparative study of a proposed time varying loudness standard.

While noise levels are most often quantified using physical quantities including A‐weighted sound pressure level, these metrics do not adequately represent the human perception of the noise. For this, loudness is a more appropriate acoustic metric as it describes the perceived acoustic intensity of a sound. Given that real sounds are often unsteady, a most useful loudness calculation will also account for the perceptional phenomena of time and temporal masking. One such model is the DIN 45631‐A1. However, this standard takes a less common approach in that it does not fully describe a methodology to calculate the unsteady loudness. It instead offers a more general procedure along which it provides open‐ended checks and balances for verifying the progress through the various calculation steps. The caveat of this is that while conditions specified by this standard may be satisfied, it has been suggested that varying results may be achieved due to the procedure’s open architecture. Using several commercial so...

Comparative study of a proposed time varying loudness standard for common sounds.

Several calculation procedures exist and are standardized for the determination of loudness of steady sounds. While loudness models for unsteady sounds do presently exist, they differ in their outcomes and have not been yet sufficiently validated using round robin or other appropriate evaluation methodology. Recently, the Deutsches Institut fur Normung (DIN) announced that it will soon issue a new standard describing a method for calculation of loudness of time‐varying sounds. However, the DIN 45631‐A1 takes a less common approach in that it does not fully describe a methodology to calculate the unsteady loudness. It instead offers a more general procedure along with open‐ended checks and balances for verifying the progress through the various calculation steps. The caveat of this is that while conditions specified by this standard may be satisfied, varying results may be achieved due to the procedures’ open architecture. Conversely, the checks and balances may be enough such that identical results are ac...