• TFMaskEval: Time Frequency Masking: Gabor Multiplier Models and Evaluation


    The most basic model for convolution algorithms is an extension of the simultaneous irrelevance model. A triangle-like function describes the masking effect in the frequency and time direction. Combined, they result in a 2-D function, which is used as convolution on the time-frequency coefficients of the given signal. The resulting information is then used to calculate a threshold function. This can be implemented as a Gabor multiplier. This very simple function should be exchanged for a more elaborate 2-D kernel. A more elaborate 2-D kernel can be developed from the first time frequency masking effect measurements of a Gaussian atom.


    An extension of the simultaneous irrelevance model is used as the most basic model for the convolution algorithm under investigation. A triangle-like function describes the masking effect in the frequency and time direction. Combined, they result in a 2-D function, which is used as convolution on the time-frequency coefficients of the given signal to calculate a threshold function. This can be implemented as a Gabor multiplier. This very simple function should be exchanged for a more elaborate 2-D kernel developed from the first time-frequency masking effect measurements of a Gaussian atom.


    After thoroughly testing this algorithm in psychoacoustic experiments, it will be implemented in STx.


    • R. Kronland-Martinet, S. Ytad, T. Necciari, Modélisation, Synthèse et Contrôle des Signaux Sonores et Musicaux of the LMA / CRNS Marseille
    • S. Meunier, S. Savel, Acoustique perceptive et qualité de l’environnement sonore of the LMA / CRNS Marseille


    This project ended on 28.02.2008 and is incorporated into the 'High Potential'-Project of the WWTF, MULAC.

  • The Vowels of Standard Austrian German


    Up to now, a thorough phonetic-acoustic and phonological description of the vowels and the vowel system of Standard Austrian German has not been provided.


    Approximately 11,000 vowels of three female and three male speakers of Standard Austrian German have been segmented and analyzed acoustically.


    Standard Austrian German discerns 13 vowels on five constriction locations:

    • pre-palatal for the /i/ and the /y/ vowels
    • mid-palatal for the /e/ and the /ø/ vowels
    • velar for the /u/ vowels
    • upper pharyngeal for the /o/ vowels
    • lower pharyngeal for /ɑ/

    Each vowel pair consists of a constricted and an unconstricted vowel. The front vowels (pre-palatal and mid-palatal) additionally distinguish rounded and unrounded vowels. The following articulatory features sufficiently discriminate all vowels:

    • [± constricted]
    • [± front]
    • [± prepalatal]
    • [± pharyngeal]
    • [± round]

    Contrary to general assumptions, F1 and F2 do not sufficiently discern the vowels of Standard Austrian German; F3 is necessary as well. Discriminatory ability is maintained over all speaking styles and prosodic positions.

  • TIFMOFUS: Time-Frequency Methods for Operators and Function Spaces

    Multilateral Scientific and Technological Cooperation in the Danube Region 2017-2018
    Austria, Czech Republic, Republic of Serbia, and Slovak Republic
    Project duration: 01.01.2017 - 31.12.2018

    Project website:

  • Time Frequency Virtual Acoustics (TF-VA)


    In the context of binaural virtual acoustics, a sound source is positioned in a free-field 3-D space around the listener by filtering it via head-related transfer functions (HRTFs). In a real-time application, numerous HRTFs need to be processed. The long impulse responses of the HRTFs require a high computational power, which is difficult to directly implement on current processors in situations involving more than a few simultaneous sources.

    Technically speaking, an HRTF is a linear time-invariant (LTI) system. An LTI system can be implemented in the time domain by direct convolution or recursive filtering. This approach is computationally inefficient. A computationally efficient approach consists of implementing the system in the frequency domain; however, this approach is not suitable for real-time applications since a very large delay is introduced. A compromise solution of both approaches is provided by a family of segmented-FFT methods, which permits a trade-off between latency and computational complexity. As an alternative, the sub-band method can be applied as a technique to represent linear systems in the time-frequency domain. Recent work has showed that the sub-band method offers an even better tradeoff between latency and computational complexity than segmented-FFT methods. However, the sub-band analysis is still mathematically challenging and its optimum configuration is dependant on the application under consideration.


    TF-VA involves developing and investigating new techniques for configuring the sub-band method by using advanced optimization methods in a functional analysis context. As a result, an optimization technique that minimizes the computational complexity of the sub-band method will be obtained.

    Two approaches will be considered: The first approach designs the time-frequency transform for minimizing the complexity of each HRTF. In the second approach, we will design a unique time-frequency transform, which will be used for a joint implementation of all HRTFs of a listener. This will permit an efficient implementation of interpolation techniques while moving sources spatially in real-time. The results will be evaluated in subjective localization experiments and in terms of localization models.


    • Main participator: Damian Marelli (University of Newcastle, Australia)
    • Co-applicants: Peter Balazs, Piotr Majdak
    • Project begin: November 2011
    • Funding: Lise-Meitner-Programm of the Austrian Science Fund (FWF) [M 1230-N13]
  • VarDiÖ: Variation and Change of dialect varieties in Austria (in apparent and real time)

    Projektteil 02 des Sonderforschungsbereichs Deutsch in Österreich. Variation - Kontakt - Perzeptionfinanziert vom FWF (FWF6002) in Kooperation mit der Universität Salzburg

    Projektleitung: Stephan Elspaß, Hannes Scheutz, Sylvia Moosmüller

    Beginn des Projekts: 1. Jänner 2016


    Gegenstand des Projekts sind die Vielfalt und die Dynamik der verschiedenen Dialekte in Österreich. Auf der Grundlage einer neuen Erhebung sollen in den nächsten Jahren unterschiedliche Forschungsfragen beantwortet werden. Diese lauten etwa: Welche Unterschiede und Veränderungen (z.B. im Wege von Konvergenz-und Divergenzprozessen) lassen sich innerhalb der und zwischen den österreichischen Dialektlandschaften beobachten? Welche Unterschiede im Dialektwandel gibt es zwischen städtischen und ländlichen Gebieten? Lassen sich Generationen- und Genderunterschiede feststellen, die den Dialektwandel betreffen? Welchen Beitrag kann ein umfassender Vergleich von ,real-time‘-und ,apparent-time‘-Analysen zu einer allgemeinen Sprachwandeltheorie leisten?

    Zur Beantwortung dieser Fragestellungen werden in der ersten Erhebungsphase an 40 österreichischen Orten Sprachproben von insgesamt 160 Dialektsprecherinnen und -sprechern aus zwei verschiedenen Altersgruppen aufgenommen und analysiert. Weiters werden von ausgewählten Sprecher/inne/n Aufnahmen im Sprachlabor durchgeführt, um Eigenheiten in der Aussprache phonetisch möglichst exakt bestimmen zu können. In der zweiten Erhebungsphase werden an 100 weiteren Standorten in Österreich ergänzende Laboraufnahmen durchgeführt, um die Unterschiede und die Bewegungen zwischen den Dialektlandschaften noch genauer analysieren zu können. Hier sollen auch neueste dialektometrische Verfahren zum Einsatz kommen, um probabilistische Aussagen in Bezug auf die Variation und den Wandel der Dialekte in Österreich treffen zu können. Die Analysen betreffen alle sprachlichen Ebenen von der Aussprache bis zur Grammatik und zum Wortschatz. Die Dokumentation der gewonnenen Daten erfolgt u. a. digital. Es ist geplant, die Daten am Ende auf der Plattform „Deutsch in Österreich“ einem breiten Publikum zugänglich zu machen, insbesondere in Form des ersten ,sprechenden Sprachatlas‘ von ganz Österreich.

    Projekthomepage der Kooperationspartner in Salzburg


  • Vibrations in Random Layers


    One of the biggest problems encountered when building numerical models for layers is the lack of exact deterministic material parameters. Therefore, stochastic models should be use. However, these models have the general drawback of overusing computer resources. This project developed a stochastic model with the ability to use a shear modulus in conjunction with a special iteration scheme allowing efficient implementation.


    With the Karhunen Loeve Expansion (KLE), it is possible to split the stochastic shear modulus, and therefore the whole system, into a deterministic and a stochastic part. These parts can then be transformed into a linear system of equations using finite elements and Chaos Polynomial Decomposition. Combining the KLE and the Fourier Transformation in combination with Plancherel's theorem enables decoupling of the deterministic part into smaller subsystems. An iteration scheme was developed which narrows the application of "costly" routines to only these smaller deterministic subsystems, instead of the whole higher dimensional (up to a dimension of 10,000) system matrix.


    As concerns about vibrations produced by machinery and traffic have increased in past years, models that can predict vibrations in soil became more important. However, since material parameters for soil layers cannot be measured exactly in practice, it is reasonable to use stochastic models.

  • Vowel and consonant quantity in Southern German varieties

    Vowel and consonant quantity in Southern German varieties: D - A - CH project granted by DFG, FWF, SNF

    Principal investigators: Felicitas Kleber, Michael Pucher, Sylvia Moosmüller†, Stephan Schmid 

    Start of the project: 1st of June 2015


    Viele Studien haben eine Beziehung zwischen diachronem Wandel und synchroner Variation, Spracherwerb, internen und externen Faktoren gezeigt. In diesem Vorhaben werden wir diese Themen mittels einer methodisch umfangreichen Studie zur (In-)Stabilität von Quantitätsverhältnissen in Vokal-Konsonant-Sequenzen (VK) in Standardvarietäten und Dialekten des süddeutschen Sprachraums untersuchen. Während die Quantitätsverhältnisse im Schweizerdeutschen diachron relativ stabil geblieben sind (auch moderne Sprachstufen haben einen Vokal- und einen Konsonantenlängen-kontrast), ist der althochdeutsche Konsonantenlängenkontrast im Standarddeutschen verloren gegangen; in den mittelbairischen Varietäten wiederum sind Vokal- und Konsonantenlänge komplementär verteilt. Die bairischen Quantitätsverhältnisse scheinen sich allerdings zu ändern, vermutlich aufgrund von Dialektausgleich. Das Vorhaben ergreift die Gelegenheit, in einer großangelegten Apparent-time-Studie diesen prosodischen Wandel im Fortschritt zu untersuchen und die instabilen Quantitätsverhältnisse mit stabileren in anderen Varietäten zu vergleichen. Das Hauptziel ist die Modellierung der Bedingungen, unter denen sich Quantitätsverhältnisse diachron ändern, um so ein besseres Verständnis prosodischer Wandelprozesse in den Sprachen der Welt zu gewinnen. Das Vorhaben enthält vier konkrete Ziele: (1) eine Typologie der Quantitäten in oberdeutschen Dialekten und den drei nationalen Standardvarietäten aufzustellen; (2) den prosodischen Wandel weiterführend und die Gründe für Wandelprozesse in einigen Varietäten zu untersuchen; (3) den Einfluss interner und externer Faktoren (z.B. Sprechgeschwindigkeit vs. Spracheinstellungen) auf die synchrone Variation in der Produktions-Perzeptionsbeziehung bei Erwachsenen zu prüfen; (4) die Entwicklung von Quantitätsverhältnissen im Erstspracherwerb und eine mögliche Beziehung zwischen synchroner Variation in Kindersprache und prosodischem Wandel zu untersuchen. Die Innovation des Vorhabens liegt in der großangelegten, Varietäten übergreifenden Apparent-time-Studie, die auch Kinder verschiedenen Alters einschließt, der Kombination aus artikulatorischen, akustischen und auditiven Methoden, und der Berücksichtigung sozialer und phonetischer Faktoren.Das geplante Projekt verbindet die am ARI (Wien) etablierten akustischen und soziophonetischen Analysen von Quantitätsverhältnissen in österreichischen Varietäten mit den am IPS (München) entwickelten akustischen, perzeptiven und physiologischen Methoden zur Produktions-Perzeptionsbeziehung bei Sprechern aller Altersgruppen und den am Phonetischen Laboratorium (Zürich) etablierten Methoden zur Typologisierung schweizerdeutscher Varietäten. Langfristig dient die Kollaboration dazu ein Lautwandelmodel an der Phonetik-Phonologie-Schnittstelle zu entwickeln, das die durch dieses Projekt gewonnenen Ergebnisse zu internen und externen Faktoren in der Stabilität von Quantität, Spracherwerb und linguistischem Wandel integriert.


  • Vowel Systems in Comparison


    This project describes vowel systems of several languages acoustically and compares them. The project's main interest is focused on languages with acoustically insufficient descriptions thus far, e.g. Albanian, Romanian, Ful, Mandinka, or Crioulo.


    Selected speakers are asked to perform a reading task and to speak spontaneously. Vowels in all positions are segmented, labeled, and analyzed. Formant frequencies (F1, F2, F3) are extracted and the vowel systems are defined.

    Language specificity affects not only the number of vowels and their features, but also the extent of variability and stability of certain vowels. A given vowel of language A might be quite stable, whereas the same vowel might exert high variability in language B. In the same way, vowels might be discerned differently. For example, pre-palatal /i/ and mid-palatal /e/ are discerned by F3 in Standard Austrian German (see diagram on SAG), whereas both mid-palatal /i/ and /e/ are predominantly discerned by F2 in Modern Standard Albanian (see diagram on MSA).


    In forensic speaker identification, thorough descriptions of the languages in question are often needed in order to conduct a thorough comparison.

  • Vowel Tensity in Standard Austrian and Standard German

    FWF DACH I 536-G20: 2011-2013
    Cooperation with the Institute of Phonetics and Speech Processing, LMU Munich.

    Project leader (Austria): Sylvia Moosmüller
    Project leader (Germany): Jonathan Harrington


    Across languages, the distinction between so-called tense and lax vowels, e.g., Miete - Mitte ("rent" - "center") or Höhle - Hölle ("cave" - "hell"), is encountered in many languages. However, many different articulatory adjustments might cause this distinction, and these are language-specific.

    In the current project, we address this issue by analysing high tense and lax vowel pairs of the type bieten - bitten ("to offer" - "to request"), Hüte - Hütte ("hats" - "hut"), and Buße - Busse ("penance" - "busses") in two related language varieties: Standard Austrian German (SAG) and Standard German German (SGG). Previous studies suggest that high lax vowel pairs like bitten, Hütte, or Busse tend to approximate their respective tense cognates bieten, Hüte, and Buße.

    The research questions were investigated by a) comparing the tense and lax vowel pairs in SAG and SGG, b) by investigating whether high lax vowel pairs approximate their tense cognates in SAG, c) by investigating whether the high vowel pairs in SAG are distinguished by quality, by quantity, or by quantity relations with the following consonant, and d) by investigating whether an ongoing sound change can be observed in SAG, with young SAG speakers exhibiting a higher degree to merge the vowels than old SAG speakers.

    Main Results:

    SGG speakers clearly distinguish the high vowel pairs by quality, whereas speaker-specific strategies can be observed in SAG, with some speakers distinguishing high tense and lay vowel pairs by quality, others merging the quality contrast, but restricting the merger to velar contexts only, and still others merging high tense and lax vowels alltogether. In case of distinction, the differences between high tense and high lax vowels are less pronounced in SAG than in SGG and still less pronounced in the speech of young SAG speakers as compared to old SAG speakers. The same result was observed for quantity distinctions: All speakers differentiate the high vowel pairs by quantity, meaning that the tense vowels of the type bieten, Hüte, and Buße are longer than their respective lax cognates. Again, the differences are most pronounced in SGG and least pronounced in the speech of the young SAG speakers, meaning that the tense vowels of the type bieten, Hüte, and Buße are truncated in the speech of young SAG speakers as compared to old SAG speakers and SGG speakers. Results on the quantity interactions of vowel + consonant sequences prove quantifying aspects in SAG. Again, some age-specific differences emerged insofar as overall, young SAG speakers have shorter durations than old SAG speakers. However, they maintain the timing relations observed for the old SAG speakers. Results on perception strongly suggest that SAG speakers make use of quantity cues in order to distinguish the vowel pairs, whereas SGG speakers rather rely on cues connected with quality. Generally, it can be concluded that quantity distinctions are more relevant in SAG than in SGG.

    Project Related Publications:

    Harrington, Jonathan, Hoole, Philip, & Reubold, Ulrich.(2012). A physiological analysis of high front, tense-lax vowel pairs in Standard Austrian and Standard German.Italian Journal of Linguistics, 24, 158-183.

    Brandstätter, Julia & Moosmüller, Sylvia. (in print).Neutralisierung der hohen Vokale in der Wiener Standardsprache – A sound change in progress? In M. Glauninger & A. Lenz (Eds.), Standarddeutsch in Österreich – Theoretische und empirische Ansätze.Vienna: Vandenhoeck & Ruprecht.

    Brandstätter, Julia, Kaseß, Christian H., & Moosmüller, Sylvia (accepted). Quality and quantity in high vowels in Standard Austrian German. In: A. Leemann, M-J. Kolly & V. Dellwo (Eds.), Trends in phonetics and phonology in German-speaking Europe. Zurich: Peter Lang.

    Cunha, Conceição, Harrington, Jonathan, Moosmüller, Sylvia, & Brandstätter, Julia (accepted). The influence of consonantal context on the tense-lax contrast in two standard varieties of German. In: A. Leemann, M-J. Kolly & V. Dellwo (Eds.), Trends in phonetics and phonology in German-speaking Europe.Zurich: Peter Lang.

    Moosmüller, Sylvia. (in print). Methodisches zur Bestimmung der Standardaussprache in Österreich. In: M. Glauninger & A. Lenz (Eds.), Standarddeutsch in Österreich – Theoretische und empirische Ansätze. Vienna: Vandenhoeck & Ruprecht (=Wiener Arbeiten zur Linguistik).

    Moosmüller, Sylvia & Brandstätter, Julia.(in print). Phonotactic Information in the temporal organisation of Standard Austrian German and the Viennese Dialect. Language Sciences.

  • Wavelet Approaches in the Fast Multipole Method


    Beside the Fast Multipole Method wavelet based approaches are of increasing interest for the fast calculation of large matrices.


    The first part of the project is the implementation of the wavelet method for the compression of the data. Next step is the investigation whether wavelet and FMM approaches can be used together and whether an additional speed up is possible.


    The aim of the project is the development of an algorithm that allows for a fast calculation of large matrices. The final aim is the possibilities to handle large acoustic problems numerically.

  • WaveletMulAc: Analytical and Numerical Properties of Wavelet Multipliers


    Gabor multipliers are an efficient time-variant filtering tool used implicitly in many engineering applications in signal processing. For these operators, the result of a Gabor transform (the sampled version of the Short Time Fourier Transform) is multiplied by a fixed function (the time-frequency mask or symbol). The result is then synthesized.

    Transforms other than the Gabor transform, particularly the wavelet transform, are more suitable for certain applications. The concept of multipliers can easily be extended in this case. This results in the introduction of operators called wavelet multipliers, which will be investigated in detail in this project. The project aims to precisely define wavelet multipliers' mathematical properties and optimize their use in applications.


    The problem will be approached using modern wavelet theory, harmonic analysis tools, and numeric tools. Formulation and demonstration of analytic statements will be conducted jointly with systematic numeric experiments in order to study the properties of wavelet multipliers.

    The following topics will be investigated in the project:

    • Eigenvalues and eigenvectors of wavelet multipliers
    • Invertibility and injectivity of wavelet multipliers
    • Reproducing kernel invariance
    • Discretization and implementation of wavelet multiplier
    • Best approximation of operators by wavelet multipliers and identification of wavelet multipliers


    The applications of wavelet multipliers in signal processing are numerous and include any application requiring time-variant filtering. Some applications of wavelet multipliers will be investigated further in the parallel projects:

    • Mathematical Modeling of Auditory Time-Frequency Masking Functions
    • Improvement of Head-Related Transfer Function Measurements
    • Advanced Method of Sound Absorption Measurements


    • Anaïk Olivero: "Expérimentation des multiplicateurs temps-échelle" (On the time-scale multipliers) Master thesis under the supervision of R. Kronland-Martinet and B. Torrésani, June 2008
  • WavletMul: Wavelet Multipliers and their Application to Reflection Measurements


    Time-variant filters are gaining more importance in today's signal processing applications. Also, there wavelet analysis has numerous applications. The goal of this project is to investigate time-variant systems based on wavelet analysis.


    The concept of multipliers can be easily extended to wavelet frames. This means the coefficients of a wavelet analysis are multiplied by a fixed symbol and then resynthesized. The influence of the special structures of these sequences on the resulting operators will be investigated.

    The theory of Pseudo-Differential Operators (PDO) can be translated to the wavelet case. How operators of interest in the investigation of multipliers, like the Kohn-Nirenberg correspondence, are translated to this case is of particular interest. Natural starting points for the research are:

    Use dilations in the definition of the spreading function instead of modulation.

    Define a special wavelet kernel function by using a weak formulation:

    < K f , g > = < k , Wg f >


    A very useful application for this project is an analysis-modification-synthesis system based on the wavelet analysis. With some language manipulation, this could be called a "Wavelet Phase Vocoder".

    The application investigated in this project is the measurement of reflection coefficients. The wavelet analysis is preferable for signals containing transient parts. It is essential to separate the impulse responses of different reflections in order to calculate the absorption coefficient of a sound-proof wall. The impulse responses can be easily separated in a scalogram, and they can be extracted by using a wavelet multiplier.


    This project ended on 28.02.2008 and is incorporated into the 'High Potential'-Project of the WWTF, MULAC.

  • Weighted and Controlled Frames


    Weighted and controlled frames were introduced to speed up the inversion algorithm for the frame matrix of a wavelet frame. In this project, these kinds of frames are investigated further.


    The frame multiplier concept is closely linked to the weighted frames concept. The frame operator of the weighted frame is simply a frame multiplier of the original frame. This project aims to explore this synergy. Finding an efficient way to invert the frame operator by applying weights to a given frame would be especially interesting. Weights are searched, for which the frame bounds are as "tight" as possible, meaning the spectrum is more concentrated. The first numerical experiments to find optimal weights have been conducted.


    Weighted frames have already been applied to wavelets on the sphere. Also, the original work by Duffin and Schaefer dealt with the problem of finding such weights for a sequence of exponentials.


    • J. P. Antoine, Unité de physique théorique et de physique mathématique – FYMA
  • WiABahn - Akustische Wirkung von gleisnahen Abschirmkanten und Bahnsteigdächern