Alan Woolley

Bio: Alan Woolley is an academic researcher from University of Edinburgh. The author has contributed to research in topics: Musical instrument & Pallet. The author has an hindex of 3, co-authored 13 publications receiving 55 citations.

The Organ: A Dangerously Inexpressive Musical Instrument

Abstract: THE DIAPASON n OCTOBER 2013 n 23 Abstract Whether mechanical organ actions allow organists to control the way in which they move the key and thus influence the transients has been discussed for many decades, and this is often given as their main advantage. However, some physical characteristics of mechanical actions, notably pluck, make it difficult for the player to control the key movement and thus vary the transient. This project looks primarily at how organists use rhythm and timing to play expressively, but also provides some evidence about whether transient variation is significant. Rhythmic variation can be through the use of deliberate “figures”, or the player may be unaware that they are making such variations. These variations in style lead to clear groupings of the pressure rise profile under the pipe and thus limit the amount of transient control possible. This is supported by informal listening tests. It also considers other factors that might lead to transient variation that are outside the player’s direct control.

Transient variation in mechanical action and electric action pipe organs

Abstract: Control of the transients by the player has often been cited as one of the most important characteristics of mechanical pipe organ actions since their reintroduction towards the middle of the last century. Previous research indicates that players do not vary the way that they move the key to a significant extent, except as the result of starting the finger movement from some distance above the key rather than in contact with it. This does not necessarily lead to an audible difference. There are, however, other factors in pipe organ action design, pipe voicing and the way in which organs are played that may lead to real or apparent transient variation irrespective of the type of action. It is well recorded that it is desirable to stagger the release of a chord starting with the pipes with least wind requirement in order to minimise the effect on the wind chest pressure particularly with traditional pressure regulators remote from the wind chest. This paper investigates some of these mechanisms and compares transient variation on mechanical action organs and electric action organs due to different playing styles.

Mechanical Pipe Organ Actions and why Expression is Achieved with Rhythmic Variation Rather than Transient Control

Abstract: Whether mechanical organ actions allow organists to control the way in which they move the key and thus influence the transients has been discussed for many decades and this is often given as their main advantage. Some characteristics of mechanical pipe organ actions, notably pluck (the initial resistance felt as the pressure difference across the pallet valve is overcome, and which, due to flexibility in the action, also results in the pallet not starting to open until the key has moved a significant distance), make it difficult for the player to control the key movement and thus the transient. This project looks at how organists use rhythm and timing to play expressively. This can be through the use of deliberate “figures”, or the player may be unaware that they are making such variations. These variations in style lead to clear groupings of the pressure rise profile under the pipe and thus limit the amount of transient control possible. Informal listening tests suggested that the transient variation measured were only discernable by the most highly trained listeners and may be less important than timing.

How Mechanical Pipe Organ Actions Work Against Transient Control

Abstract: This paper summarises work published and presented previously, supported by additional material. It can be clearly demonstrated by blowing an organ pipe that its transient can be varied, although the effect is not generally considered ‘musical’. It has been debated for several decades whether mechanical pipe organ actions allow the player to vary the transient by the way in which the key is moved. Opinions vary from transient control being fundamental to organ playing to it not being possible. This work shows that the physical characteristics of mechanical organ actions work against transient control and this is corroborated by measurements of key and pallet movements and pressure changes whilst organists are playing. It also looks at what other methods organists are using in order to play expressively. The paper also considers how transients might vary due to other characteristics of organs that are outside players’ direct control but might lead them to believe that variations are due to differences in their key movements.

A physical method for measuring speech-transmission quality

Abstract: A physical method for measuring the quality of speech‐transmission channels has been developed. Essentially, the method represents an extension of the Articulation Index (AI) concept, which was developed mainly to account for distortions in the frequency domain (noise, bandpass‐limiting). The underlying concept of the present approach, based on the Modulation Transfer Function (MTF) of a transmission channel, has been adapted to account for nonlinear distortions (peak clipping) as well as for distortions in the time domain (reverberation, echoes, AGC). The resulting index, the Speech‐Transmission Index (STI), has been correlated with subjective intelligibility scores obtained on 167 different transmission channels with a wide variety of disturbances. The relative predictive power of the STI, expressed in PB‐word score, appeared to be 5%. This accuracy is comparable with results obtained from subjective measurements when about four talkers and four listeners are used. Expressed in terms of signal‐to‐noise ratio, the accuracy is about 1 dB. Pilot studies have been carried out to evaluate the use of the STI for testing digital speech‐transmission channels.

Liquid-Fuel Behavior in an Aeronautical Injector Submitted to Thermoacoustic Instabilities

Abstract: The aim of this work is to study the role of the liquid phase in the thermo-acoustic coupling which subsequently leads to combustion instabilities. Experimental investigations were performed on an actual multipoint spray injector geometry used in real aeronautical combustors. A test bench was specifically designed with continuously changeable acoustics conditions; which allows obtaining a stable or an unstable flame for identical flow conditions. Different laser-based visualization techniques were used to analyze the kerosene spray (both liquid and vapor phases) and the heat released from the flame. A phase-averaged data processing of the Planar Laser-Induced Fluorescence (PLIF) images reveals the complex unsteady behavior of the liquid phase and its coupling with pressure fluctuations in the chamber and the heat released from the flame. The origins of the spray fluctuations are also analyzed. Nomenclature = surface of the control system boundary, m 2 = volume of the control system, m 3 = heat capacity ratio = characteristic time, s dA = surface integration variable, 1 m 2 dt = time integration variable, 1 s dV = volume integration variable, 1 m 3 D REF = reference diameter F = Flame Describing Function FSP = Fuel Split Parameter GER = Global Equivalent Ratio I = light intensity over camera dynamics, # counts IEL = Inner Exhaust Length, mm J = momentum ratio air m  = air mass flow rate, g/s P f m ,  = fuel mass flow rate on the pilot system, g/s MP f m ,  = fuel mass flow rate on the multipoint system, g/s p' = acoustic pressure, Pa p = averaged pressure, Pa q' = unsteady heat release, W/m 3 Ra = local Rayleigh index T = instability cycle period, s T air = air inlet temperature, K u' = acoustic velocity, m/s

Current State-of-the-Art and New Directions in Strategic Environmental Noise Mapping

Abstract: Environmental noise mapping has the potential to act as a powerful resource for policymakers as a decision support tool for the mitigation of the negative effects of environmental noise pollution and its impact on public health. The aim of this paper is to review current state-of-the-art developments in how the strategic noise mapping (SNM) process has progressed at the EU level since the introduction of the Environmental Noise Directive (END) in 2002. Reviewing such developments is important because of the relevance of SNM to public health. In this regard, the development of a new standardized noise calculation method (i.e. CNOSSOS-EU) is also considered, as well as the future potential for noise mapping and the impact of technology on the development of noise pollution assessment.

Red shift, blue shift: investigating Doppler shifts, blubber thickness, and migration as explanations of seasonal variation in the tonality of Antarctic blue whale song.

Abstract: The song of Antarctic blue whales (Balaenoptera musculus intermedia) comprises repeated, stereotyped, low-frequency calls. Measurements of these calls from recordings spanning many years have revealed a long-term linear decline as well as an intra-annual pattern in tonal frequency. While a number of hypotheses for this long-term decline have been investigated, including changes in population structure, changes in the physical environment, and changes in the behaviour of the whales, there have been relatively few attempts to explain the intra-annual pattern. An additional hypothesis that has not yet been investigated is that differences in the observed frequency from each call are due to the Doppler effect. The assumptions and implications of the Doppler effect on whale song are investigated using 1) vessel-based acoustic recordings of Antarctic blue whales with simultaneous observation of whale movement and 2) long-term acoustic recordings from both the subtropics and Antarctic. Results from vessel-based recordings of Antarctic blue whales indicate that variation in peak-frequency between calls produced by an individual whale was greater than would be expected by the movement of the whale alone. Furthermore, analysis of intra-annual frequency shift at Antarctic recording stations indicates that the Doppler effect is unlikely to fully explain the observations of intra-annual pattern in the frequency of Antarctic blue whale song. However, data do show cyclical changes in frequency in conjunction with season, thus suggesting that there might be a relationship among tonal frequency, body condition, and migration to and from Antarctic feeding grounds.