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Average Maximum Sound Level: A Complementary Metric for Environmental Noise Assessment
Ben Hall · International Congress on Acoustics 2026 · Aug 2026
Many existing environmental approvals and licence conditions in Australia specify noise limits as an A-weighted 'average maximum' or 'LAmax,adj,T'. These descriptors originated in an era when analogue sound level meters were used and compliance was assessed by observing and informally averaging meter needle peak excursions. Modern digital sound level meters do not reproduce that observational process directly, and practitioners have commonly adopted the LA10 despite it being a time-exceedance percentile rather than an average of maxima. This paper presents the Average Maximum Sound Level (LAFmax,T), a repeatable empirical method for calculating the arithmetic mean of maximum levels over consecutive time intervals. The method provides a practical and repeatable approximation of the historical “average maximum” concept, reduces subjective variability, and offers a more appropriate legacy-assessment descriptor than LA10 in environments characterised by recurring maxima. A formal technical specification, ILTS-AC-001:2025, has been developed to support consistent implementation.
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Vibration Measurement Methodologies Mounting Techniques and Effectiveness
Andrew Durrer · International Congress on Acoustics 2026 · Aug 2026
Ground vibration measurements are widely used in acoustics and environmental assessments to evaluate vibration impact from sources such as construction, transportation, industrial activity and more. The accuracy of triaxial ground vibration data depends strongly on the mounting technique used to couple sensors to the ground and this paper’s goal is to assess the commonly used mounting techniques and compare to some more creative yet easy to access mounting techniques (ie. Ground screws). Measurements are completed at multiple sites representing typical ground conditions, comparing surface-mounted, shallow-buried, mechanically anchored, and foundation mounted sensor installations. The influence of mounting technique on coupling quality, frequency response, measurement errors and measurement repeatability is evaluated under a controlled environment. This paper hopes to provide practical recommendations for field deployment of triaxial vibration sensors and support improved consistency and comparability of ground vibration measurements in acoustics and environmental assessments.
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Preliminary Nord2000 noise results for Queensland NGR trains
Asbjorn Hansen · International Congress on Acoustics 2026 · Aug 2026
A sizable noise measurement programme was undertaken prior to the construction of a large infrastructure project in Southeast Queensland. The data acquired prior to any construction was used for the verification of a rail noise model where the Kilde calculation algorithm was used for the noise predictions and model verification. The data obtained in the pre-construction phase included video recordings with simultaneously recorded noise levels near the rail track. The acquired noise data also include noise levels recorded at the facades of twelve dwellings situated from 35 m to 270 m from the rail tracks. It should be noted that the rail corridor only is used for passenger trains and that the majority of trains operating on the tracks are NGR trains. The data was at a later stage revisited to develop the Nord2000 rail coefficients for the NGR trains and compare predicted noise levels at the facades of the dwellings when using the two different calculation algorithms. This paper compares the predicted noise levels of the Kilde and the Nord2000 calculation algorithms to the measured noise levels.
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Assessing the Relationship Between Weather Conditions and Acoustic Activity of Insects and Fauna Using Noise Monitoring
Lizeth Valderrama, Ben Hall · International Congress on Acoustics 2026 · Aug 2026
This paper investigates the relationship between weather conditions and environmental noise generated by fauna and insects at a site in Queensland, Australia, characterised by dense vegetation and proximity to a significant water source. Twelve months of continuous environmental noise monitoring (April 2025 to March 2026) were analysed to examine how temperature, humidity, rainfall and wind are associated with diel and seasonal acoustic activity across species. Audio recordings were processed with an Artificial Intelligence (AI) based tool programmed for audio recognition to identify vertebrate fauna and insect callers; detections were aggregated by hour and month alongside meteorological variables and noise descriptors. Spearman correlations were computed at hour of day resolution per month and pooled annually across all twelve months. Nineteen vertebrate and insect taxa were detected, and three independent acoustic guilds were identified: a temperature-driven daytime cicada chorus, a wind- and rain-tolerant bird dawn chorus, and a humidity-loving nocturnal owl and frog signal. Anthropogenic noise was negligible. The study demonstrates the value of long-term passive acoustic monitoring combined with the AI audio recognition tool for characterising species activity and environmental noise patterns in ecologically sensitive environments.
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Risks of optimising the Kilde 67 130 calculations in SoundPLAN
Asbjorn Hansen · Acoustics 2025 · Aug 2026
Many existing environmental approvals and licence conditions in Australia specify noise limits as an A-weighted 'average maximum' or 'LAmax,adj,T'. These descriptors originated in an era when analogue sound level meters were used and compliance was assessed by observing and informally averaging meter needle peak excursions. Modern digital sound level meters do not reproduce that observational process directly, and practitioners have commonly adopted the LA10 despite it being a time-exceedance percentile rather than an average of maxima. This paper presents the Average Maximum Sound Level (LAFmax,T), a repeatable empirical method for calculating the arithmetic mean of maximum levels over consecutive time intervals. The method provides a practical and repeatable approximation of the historical “average maximum” concept, reduces subjective variability, and offers a more appropriate legacy-assessment descriptor than LA10 in environments characterised by recurring maxima. A formal technical specification, ILTS-AC-001:2025, has been developed to support consistent implementation.
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Comparison of data transmission protocols for remote and real-time environmental monitoring
Ben Hall · Acoustics 2024 · Aug 2024
Environmental monitoring systems, particularly those involving remote sensors, rely heavily on efficient data transmission protocols to deliver real-time information for centralized analysis. This paper provides a comparative analysis of six key data transmission protocols—MQTT, HTTP, FTP, WebSockets, RPC, and WebDAV—assessing their suitability for remote and real-time environmental monitoring applications. The comparison focuses on four critical factors: connection overhead, latency, power consumption, and connection stability. Our analysis reveals that MQTT and WebSockets are the most efficient choices for real-time, low-power applications.
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Review of audio compression formats for post-processing
Ben Hall · Acoustics 2024 · Aug 2024
In this paper we investigate the impact of audio compression on the analysis of noise metrics using sound level meters. Various audio compression formats, including MP3, AAC, Ogg Vorbis, Opus, FLAC, ALAC, WavPack, and Speex, are applied to a series of test signals. Key noise metrics such as Leq, Lmax, Lmin, SEL,, statistical percentiles and 1/3 octave band analysis were compared.
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Limit of predicted road noise emissions due to traffic constraints - Part 2
Ben Hall · International Congress on Acoustics 2010 · Aug 2010
There is a limit to the number of vehicles that can travel on a road section per hour. Vehicle speed will decrease as the road becomes congested. In Queensland, road traffic noise emissions are based on the Calculation of Road Traffic Noise method (CoRTN). This method is dependent on both traffic volumes and speed, among other parameters, however in the current calculation method, speed is assumed to be constant. By incorporating the inherent traffic speed constraints a more accurate method of calculating the L10, 1hr is obtained.
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Limit of predicted road noise emissions due to traffic constraints
Ben Hall · Acoustics 2009 · Nov 2009
There is a limit to the number of vehicles that can travel on a road section per hour. As the traffic numbers increase, the traffic speeds decrease. In Queensland, road traffic noise emissions are based on the Calculation of Road Traffic Noise method (CoRTN). This method is dependent on both traffic volumes and speed, among other parameters. This paper presents a method for determining the upper limit of noise emissions from a road string, based on the CoRTN method. It is shown that there is point where due to the higher traffic volumes, there is a reduction of vehicle speed, causing the calculated noise emissions to decrease. These results have implications for the mitigation requirements for high traffic volume roads.
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Calculation of overall community noise impact due to a change in noise source emissions
David Davis, Ben Hall · Acoustics 2008 · Aug 2008
Calculation of overall community noise impact due to a change in noise source emissions