There is a need for a model that identifies underlying dimensions of soundscape perception, and which may guide measurement and improvement of soundscape quality With the purpose to develop such a model, a listening experiment was conducted One hundred listeners measured 50 excerpts of binaural recordings of urban outdoor soundscapes on 116 attribute scales The average attribute scale values were subjected to principal components analysis, resulting in three components: Pleasantness, eventfulness, and familiarity, explaining 50, 18 and 6% of the total variance, respectively The principal-component scores were correlated with physical soundscape properties, including categories of dominant sounds and acoustic variables Soundscape excerpts dominated by technological sounds were found to be unpleasant, whereas soundscape excerpts dominated by natural sounds were pleasant, and soundscape excerpts dominated by human sounds were eventful These relationships remained after controlling for the overall soundscape loudness (Zwicker's N(10)), which shows that 'informational' properties are substantial contributors to the perception of soundscape The proposed principal components model provides a framework for future soundscape research and practice In particular, it suggests which basic dimensions are necessary to measure, how to measure them by a defined set of attribute scales, and how to promote high-quality soundscapes

A principal components model of soundscape perception

The development and application of the emotional dimensions of a soundscape

https://www.annemergmed.com/article/S0196-0644(05)81076-5/pdf

Lights and siren: A review of emergency vehicle warning systems

Propeller design is a complex task that involves a variety of disciplines such as: aerodynamics, structural analysis, and acoustics. A new method of designing an optimal propeller which is based on a MDO (Multidisciplinary Design Optimization) approach is presented. By combining various analysis tools with an optimization tool, a powerful and flexible design method is obtained. During the design process three different optimization schemes are used, leading the design to its optimal goal. This new method is applied for the design of a propeller for an Ultralight aircraft. Several optional designs for different design goals are presented. The results of the new method are compared with results of the classical design method, based on Betz's condition, which considers only the aerodynamic performance of the propeller. The importance of addressing the characteristics of the entire air-vehicle, its aerodynamic characteristics and its propulsion system (engine, gear box, etc.), rather than only the isolated propeller, is emphasized.

Optimization of Propeller Based Propulsion System

Experiments were conducted to explore the relationship between wind instrument dyad timbres and verbal attributes drawn from the musicological literature in order to compare and contrast results with studies using artificial stimuli and amusical rating scales. In the first experiment, all adjectives in Piston9s (1955) "Orchestration" were collated and subsequently reduced to 61 examples. A checklist procedure was used in response to the dyad timbres to further reduce the set of adjectives to 21. The 21 adjectives were used in verbal attribute magnitude estimation of the 10 wind instrument dyad timbres. Principal components analysis of ratings revealed four verbal attribute factors, accounting for 90.604% of the variance: power, strident, plangent, and reed. Correlational analyses demonstrated an improvement in mapping between the ratings and perceptual similarity spaces over the procedure used in Part I of this study. The two-dimensional timbral circumplex was interpreted as having a principal dimension of nasality versus richness and a secondary dimension of reediness versus brilliance.

Verbal Attributes of Simultaneous Wind Instrument Timbres: II. Adjectives Induced from Piston's "Orchestration"

Sixteen brief sounds (music, vehicle sounds, and artificial sounds) were judged on each of 15 bipolar scales by 20 subjects. Without instructions, subjects use the descriptors “loud” and “noisy” as synonomous. On the other hand, subjects do not equate either loudness or noisiness with acceptability, although there appears to be a moderate relationship when only vehicle or aircraft sounds are rated by subjects. The implications of these findings for instructions in psychoacoustic research are discussed.

Multiple ratings of sound stimuli.

Two series of psychoacoustic tests were conducted to determine the applicability of the psychophysical theory of signal detectability (TSD) to prediction of the aural detectability of noise signatures in differing noise backgrounds. The first series of tests produced data supporting development of a simplified graphical prediction method based on TSD. A second series validated the precision and accuracy of the prediction method under quasi-realistic conditions. Predicted levels of performance were typically within one or two dB of the data.

Prediction of aural detectability of noise signals.

The effects on perceived noisiness of spectral and temporal combinations of stimuli at varying durations were determined by 20 college students in an anechoic chamber. Several recordings of turboprop, turbofan, turbojet, and helicopter flyovers were also included in the list of stimuli. The results indicated that the most accurate predictor of the judged noisiness was perceived noise level with tone and duration corrections as outlined by the Federal Aviation Administrations (1968) aircraft certification procedure. To illustrate the responsiveness of effective perceived noise level (EPNL) over perceived noise level (PNL) in predicting the noisiness of stimuli, the results of the duration test revealed that, at judged equal noisiness, 75% of the data were within 4 dB of the standard signal for EPNL with the FAA tone and integrated duration measure as compared to 11 dB for PNL.

Effects of Temporal and Spectral Combinations on the Judged Noisiness of Aircraft Sounds

: Laboratory experiments were undertaken to develop improved aural detection criteria for light aircraft. Specifically two series of psychoacoustic judgment tests were conducted to determine the applicability of the psychophysical Theory of Signal Detectability (TSD) to prediction of the aural detectability of light aircraft noise signatures in jungle noise backgrounds. The first series of tests produced data supporting development of a simplified graphical prediction method based on TSD. The second testing program validated the precision and accuracy of the prediction method under quasi-realistic listening conditions. Predicted levels of performance were typically within one or two dB of the data averaged for all observers.

Predicting Aural Detectability of Aircraft in Noise Backgrounds

The executive summary and results are presented that evaluate in a laboratory setting the relative annoyance of transmission line and transformer noise along with shaped noise and other environmental noises. Thirty-two test subjects made paired comparisons of the annoyance of 19 signals under free field listening conditions.

Ricarda L. Bennett

Papers

Multiple ratings of sound stimuli.

Prediction of aural detectability of noise signals.

Effects of Temporal and Spectral Combinations on the Judged Noisiness of Aircraft Sounds

Predicting Aural Detectability of Aircraft in Noise Backgrounds

Initial study on the effects of transformer and transmission line noise on people. Volume 1. Annoyance. Final report