"The answer is blowin' in the wind" - case study of a perforated roof screen

A recently-completed building was fitted with a roof screen fabricated from perforated sheet metal panels having "U"-shaped upturned flanges. When wind impinges on the panels, complex tone clusters are generated, leading to complaints from the occupants. The unusual character of the tonal spectrum is reminiscent of a film sound effect intended to simulate a hovering extraterrestrial spacecraft. After some preliminary (but inconclusive) field investigations, it was decided to test samples of the perforated panel in a large commercial wind tunnel where the speed and angle of the airstream could be controlled. Tones generated in the tunnel were found to occur in groups or clusters - these are most pronounced when the airstream's angle of incidence is close to grazing. Gradually increasing airspeed caused the frequency of the tones to "jump" from one cluster to the next higher cluster. The physical principles of the tone-generating mechanism are not fully understood; however, it appears that structural resonances in the panel flanges are excited by air flowing over the perforate. Some form of a positive structural-acoustical feedback loop is involved since a) the frequencies within each tone cluster are quite stable and, b) damping the panel flanges extinguishes the tones.

Phonetics of White Hmong vowel and tonal contrasts

Hmong languages, particularly White Hmong, are well studied for their complex tone systems that incorporate pitch, phonation, and duration differences. Still, prior work has made use mostly of tones elicited in their citation forms in carrier phrases. In this paper, we provide a detailed description of both the vowel and tone systems of White Hmong from recordings of read speech. We confirm several features of the language, including the presence of nasal vowels (rather than derived nasalized vowels through coarticulation with a coda [ŋ]), the description of certain tone contours, and the systematic presence of breathy and creaky voice on two of the tones. We also find little evidence of additional intonational f0 targets. However, we show that some tones vary greatly by their position in utterance, and propose novel descriptions for several of them. Finally, we show that $\textrm{H}1^{\!*}$ –H2*, a widely used measure of voice quality and phonation in Hmong and across languages, does not adequately distinguish modal from non-modal phonation in this data set, and argue that noise measures like Cepstral Peak Prominence (CPP) are more robust to phonation differences in corpora with more variability.

Mesoamerica

The Mesoamerican linguistic area is rich with prosodic phenomena, including a wide variety of complex tone, phonation, stress, and intonational systems. The diversity of prosodic patterns in Mesoamerica reflects the extreme time-depth and complex history of the languages spoken there. This chapter surveys the prosody of Mesoamerican languages and some past analyses of their structures. Topics include the areal distribution of tonal complexity; interactions between stress, tone, and segmental contrasts; the phonetics of tone and phonation; metrical structure; and higher-level prosodic phenomena. Case studies from different languages also highlight interactions between morphological and word-prosodic structure. These topics underscore the importance of research on Mesoamerican languages to both phonological theory and linguistic typology.

Mainland South East Asia

The languages of Mainland South East Asia belong to five language phyla, yet they are often claimed to constitute a linguistic area. This chapter’s primary goal is to illustrate the areal features found in their prosodic systems while emphasizing their understated diversity. The first part of the chapter addresses the typology of word-level prosody. It describes common word shapes and stress patterns in the region, discusses tone inventories, and argues that beyond pitch, properties such as phonation and duration frequently play a role in patterns of tonal contrasts. The chapter next shows that complex tone alternations, although not typical, are attested in the area. The following section reviews evidence about prosodic phrasing in the area, discusses the substantial body of knowledge about intonation, and reconsiders the question of intonation in languages with complex tone paradigms and pervasive final particles. The chapter concludes with strategies for marking information structure and focus.

Representation and the Computation of Long Distance Tone Processes

This paper shows how enhancing the representation, while fixing the logical power of computation, provides a better characterization of the computationally complex tone processes, the unbounded circumembient (UC) processes noted in Jardine (2016). Using Autosegmental Representations, we define tone-TBU associations as quantifier-free least fixed point transductions, which allow us to extend the notion of subsequentiality to the otherwise non subsequential UC processes.

Iambic and Trochaic Rhythm in Jieyang (Southern Min)

This paper examines the application of the Iambic/Trochaic Law to complex tone languages like Jieyang (Teochew, Southern Min). With bidirectional tone sandhi on top of its six-tone inventory, duration and intensity measurements were obtained and fitted into Linear Mixed Effects Regression models to inspect whether duration and intensity contrasts of the two sandhi types match the predictions based on the Law. Results confirmed an interaction between rhythmic type and sandhi type, and that prominence indicated by duration and intensity contrasts largely behaves the way as predicted by the Law. This suggests that tone sandhi can be metrically-motivated via duration and intensity, contributing to the rhythmic organization of tone languages altogether.This paper has provided novel support for metrical prominence of tone languages based on the Iambic/Trochaic Law, adding complex tone languages and production results to the recent literature on rhythmic groupings.

Evidence for Linear but Not Helical Automatic Representation of Pitch in the Human Auditory System

The perceptual organization of pitch is frequently described as helical, with a monotonic dimension of pitch height and a circular dimension of pitch chroma, accounting for the repeating structure of the octave. Although the neural representation of pitch height is widely studied, the way in which pitch chroma representation is manifested in neural activity is currently debated. We tested the automaticity of pitch chroma processing using the MMN—an ERP component indexing automatic detection of deviations from auditory regularity. Musicians trained to classify pure or complex tones across four octaves, based on chroma—C versus G (21 participants, Experiment 1) or C versus F# (27, Experiment 2). Next, they were passively exposed to MMN protocols designed to test automatic detection of height and chroma deviations. Finally, in an “attend chroma” block, participants had to detect the chroma deviants in a sequence similar to the passive MMN sequence. The chroma deviant tones were accurately detected in the training and the attend chroma parts both for pure and complex tones, with a slightly better performance for complex tones. However, in the passive blocks, a significant MMN was found only to height deviations and complex tone chroma deviations, but not to pure tone chroma deviations, even for perfect performers in the active tasks. These results indicate that, although height is represented preattentively, chroma is not. Processing the musical dimension of chroma may require higher cognitive processes, such as attention and working memory.