Judit Angster

Fraunhofer Institute for Building Physics IBP | IBP · Department of Acoustics

Dynamic lingual organ pipes utilize a blown open free tongue which allows for changing the loudness of the pipe by the blowing pressure with maintaining a steady pitch. This principle is in contrast with traditional reed pipes that have blown closed tongues and always operate at a specified windchest pressure. A physics-based model of the sound ge...

This paper presents the experimental examination of an alternative lingual organ pipe construction that uses a free tongue which, in contrast with traditional lingual organ pipes, operates in a blown open manner. A possible advantage of the construction is that it can enable changing the windchest pressure and thus, achieving an extended dynamic ra...

A three-dimensional coupled vibroacoustic finite element model for physics-based simulations of the sound generation by mallet percussion instruments in the time domain is discussed in the present paper. The mechanical model takes the orthotropic material properties of the wooden sound bars and the nonlinear nature of the interaction force between...

En este trabajo se presentan explicaciones científicas para tener un mejor entendimiento de cómo funcionan los órganos tubulares y revisar algunas creencias comunes en su construcción, buscando mejorar este arte.

Creating a musical instrument often involves designing acoustical resonators. The natural frequency and the quality factor of the resonator are affected by the radiation impedance to a significant extent. Therefore attaining as much a priori knowledge as possible on the radiation characteristics is desirable. On the other hand, for the sake of effi...

Throughout the world, musical instruments are deeply rooted in cultural traditions. They are part of our cultural heritage, and their preservation and further development deserves our utmost attention. For many years, the Fraunhofer Institute for Building Physics IBP has been engaged in the research of European musical instruments, the pipe organ i...

This chapter is an overview of the characteristic sound properties of flue organ pipes. The characteristic properties of the stationary spectrum and attack transient have been surveyed and assigned to properties of the physical systems (air column as acoustic resonator, air jet as hydrodynamic oscillator, and pipe wall as mechanical resonator) invo...

Sopranorecorders are among the most popular wind instruments in music education for children. As these instruments are played by amateurs, they should be easy to play even by beginner players. The investigations reported in this paper were initiated by an instrument maker company. It was found that their plastic sopranorecorders often had unsatisfa...

The pipe organ produces a majestic sound that differs from all other musical instruments. Due to its wide tonal range, its ability of imitating the sound of various instruments, and its grandiose size, the pipe organ is often called the “king of musical instruments”. The richness and variety of sound color (timbre) produced by a pipe organ is very...

Although sulfuryl fluoride (SO2F2) is an efficient fumigant that does not react with the surface of indoor materials and does not reduce the stratospheric ozone shield, there are some concerns about its use. It is a toxic gas that attacks the central nervous system, and its global warming potential (GWP) value is 4780 for 100 years’ time. Therefore...

The sound characteristics of both labial and lingual organ pipes are affected to a great extent by the reflection properties of the resonators. In this paper, the reflection properties of sloped pipe terminations are examined and the possible applications in organ building practice are investigated. Sloped shallots of reed organ pipes with differen...

In a traditional pipe organ, the dynamic range of both labial (flue) and lingual (reed) pipe ranks are strictly limited as each rank is tuned and voiced to a nominal windchest pressure. Changing this pressure not only affects the amplitude of the radiated sound but both the pitch and the timbre of the pipes. A new pipe construction with a blown ope...

To study the relationship between the physical structure and the timbre of Chinese Sheng, a physical model of Sheng and its sound synthesis method are proposed. Based on the vibration model of reed tongue, the equivalent circuit of Sheng pipe is constructed by considering the transfer matrices of tone hole and tuning slot. By combining the reed and...

Within the framework of a European research project exciting new results have been achieved recently in the research of lingual organ pipes. The main objectives of the project are to solve practical problems of the dimensioning of reed organ pipes, to develop innovative methods and software for helping the sound design work of organ builder enterpr...

In a traditional pipe organ the pipe ranks are composed of labial (flue) and lingual (reed) pipes. Both kinds of ranks are tuned and voiced to a nominal windchest pressure. Changing this pressure not only affects the volume of the radiated sound but both the pitch and the timbre of the pipes. This means a strict limitation to the dynamic range of t...

In this article, a photothermal technique is presented to detect carbon nanoparticles in suspension and to determine their concentration using the photothermal lens effect and the photothermal beam deflection. Both methods are well researched and described in the corresponding literature. The experimental setup consists of an excitation and a probe...

The photoacoustic effect has been studied intensively using light sources emitting in the infrared (IR) region. Corresponding photons lead to excitations of vibrational–rotational energy levels. Subsequent de-excitations by collisions with the surrounding molecules can increase the translational energy of these molecules. Consequently, by irradiati...

Framed by a common research program of Chinese Academy of Sciences and of the Fraunhofer Gesellschaft, a cooperation project on the acoustics of Chinese and European wind instruments has been established. The sound radiation pattern of the Sheng, which is a traditional Chinese mouth organ with lingual pipes, was investigated by a microphone array s...

An acoustic model suitable for the characterization of tuning slots of labial organ pipes is presented in this paper. Since the tuning slot arrangement is similar (but not identical) to that of toneholes in woodwind instruments, the adaptability of the well-established tonehole model for the specific problem is examined. A numerical model utilizing...

A sensitive detection of ammonia in parts per billion by volume is described. The system based on photoacoustic spectroscopy (PAS) consists of distributed feedback laser diode emitting near 1,531.7 nm and a compact PA cell at double-pass configuration. In order to optimize the signal background ratio of the system, two types of modulations were tes...

Framed by a common research program of Chinese Academy of Sciences and of the Fraunhofer Gesellschaft a cooperation project on the acoustics of Chinese and European wind instruments has been established. A first set of experiments is dedicated to reed vibration and sound of individual pipes of a sheng, a typical Chinese free-reed instrument. The in...

The effect of tuning slots on the sound characteristics of labial organ pipes is investigated in this paper by means of laboratory experiments. Besides changing the pitch of the pipe, the tuning slot also plays an important role in forming the timbre. The objectives of this contribution are to document the influence of tuning slots built with diffe...

The focus of investigations was the influence of certain shallot parameters on the sound of reed pipes. Since the dimensioning of organ pipes is mainly based on the experience of organ builders at present, the aim is to provide scientific data for organ builders explaining the influence of various shallot parameters on the sound. Due to this knowle...

Lingual organ pipes produce sound by means of the interaction of a vibrating tongue and an acoustic resonator. The pitch of the pipe is determined by the frequency of tongue vibration, whereas the sound character is mostly influenced by the resonator. The two components form a strongly or weakly coupled vibroacoustic system depending on the pipe fo...

An optimization method, based on an acoustic waveguide model of chimney and resonator, was developed and tested by laboratory measurements of experimental chimney pipes. The dimensions of the chimney pipes are modified by the optimization algorithm until the specified fundamental frequency is achieved, and a predetermined harmonic partial overlaps...

Although organ flue pipes have been widely studied, the same claim cannot be made for pipe organ reed stops. Given certain design constraints, such as the type of reed stop being voiced and the desired tone quality, the reed voicer must use consummate skill to curve the reed tongue so as to produce the best and most stable tone as well as to guaran...

At the Fraunhofer IBP in Stuttgart a research organ has been built for scientists. Its transparency and unique design allows the demonstration of research results, the investigation of technical and sound problems in organ building as well as the audible testing of sound ideas. Some of the special design features are: The wind system can be switche...

Sound design methods for flue organ pipes can be developed for the practical application in organ building due to the high performance of modern computers and the advanced level of the scientific research on flue organ pipe acoustics. The research of Neville Fletcher and the team around him has contributed in a high extent to the scientific underst...

In the present contribution optimization and simulation methods are investigated in order to attain optimal scaling of labial organ pipes. The goal is to determine the optimal dimensions of the pipe, by which a desired steady state sound spectrum can be achieved. By modifying the geometry of the pipe body, the eigenfrequencies of the acoustic reson...

Im Verlaufe der Jahrhunderte wurde stets nach neuen Möglichkeiten gesucht, der Orgel neue Klänge zu entlocken. In der musikalischen Romantik wurden zu diesem Zweck vermehrt Pfeifen mit Expressionen, das heißt mit kleinem Fenster am oberen Ende des Resonators, eingesetzt. In diesem Vortrag wird erläutert, in welcher Weise die Breite und Höhe sowie d...

In the sound spectrum of flue organ pipes in addition to the usual harmonic partials, sometimes a series of equidistant but not harmonic lines can be found. This phenomenon has been observed in the recorded sound of pipes from different pipe ranks. The second set of spectral lines is similar to "frequency combs" used in optics for accurate measurem...

Zinc is being used only rarely for organ pipes, since high quality material has not been available. The slightly harder metal makes manual processing of the pipes more complicated for the voicer. Nevertheless zinc is much more cost‐efficient. Grillo Werke (Germany) has developed a “soft zinc strip” which is significantly better, as far as workabili...

Since old churches have had heating installed, more complaints have arisen of organs sounding out of tune. Sound frequency of organ pipes is dependent on air temperature. Old churches tend to have very large volumes, so are typically heated just before and during services in wintertime, in order to reduce energy usage. Warm air plumes rise at radia...

Given certain design constraints, such as the type of stop being voiced and the desired tone quality, reed voicers must use consummate skill to curve each tongue so as to produce the best and most stable tone, as well as maintain a consistent tone quality across an entire rank of pipes. The curvature given to a reed tongue influences not only the h...

Designing and manufacturing processes of organ pipes are still based on traditional prototyping methods and applying step-by-step tuning and voicing adjustments. To speed up this rather time and resource consuming procedure, a modeling approach is being developed. To be able to simulate complex physical phenomena of the sound generation process, a...

In order to investigate the physical processes involved in the build-up of the sound signal in a labial organ pipe a pipe foot model has been developed. The main important parameters, such as positions of the lower and upper lips, the wind pressure in the pipe foot, and the width of the flue, can be adjusted by means of this model. Moreover, differ...

Given certain design constraints, such as the type of stop being voiced and the desired tone quality, organ reed voicers must curve each tongue so as to produce the best and most stable tone, as well as maintaining a consistent tone quality across an entire rank of pipes. This study investigated the effects of varying tongue curvatures on two pipes...

Bei vielen Kirchenorgeln machen sich im Winter Verstimmungen im Orgelklang bemerkbar. Vor Spielbeginn wird die Kirche in relativ kurzer Zeit aufgeheizt. Zum einen entstehen dadurch innerhalb des Orgelgehäuses verschiedene Temperaturzonen, zum anderen werden die sich in bereits erwärmter Umgebung befindenden Orgelpfeifen mit Luft aus dem noch kalten...

A flue organ pipe can be excited in various acoustic modes by changing the air pressure supplied to it. This research aims to reconstruct this behavior from the result of numerical flow simulation of a jet deflected by sound and from physical modeling simulation of the total sound production system. In the numerical flow simulation, motion of the j...

In order to understand the physical processes involved in the build-up of the sound signal in a pipe (in our case a labial organ pipe) a pipe-foot model has been developed, with which the main important parameters, such as positions of the lower- and upper-labium, the wind pressure in the foot and the width of the flue can be adjusted. Moreover, di...

No PDF available ABSTRACT The sound quality of an organ pipe is mainly influenced by the attack transients. This onset is first dominated by the edge tone, while later the pipe resonator will play a more important role. To understand the physics of a flue organ pipe, it is necessary to analyse the edge tone, the acoustic properties of the pipe reso...

Flow visualization by the particle imagevelocimetry(PIV) is expected to provide quantitative information based on high resolution from the use of sheetlike laser pulses. This PIV technique is applied to investigate the difference in jet‐flow structure of organ pipes when the ear (small plate standing at each side of the mouth) is used or not. The e...

Temporally resolved schlieren flow visualization and Laser-Doppler Anemometry (LDA) measurements have been performed on real flue organ pipes during the stationary state as well as during the attack transient. The techniques prove highly efficient in providing information on the details of the flow. The measurements reveal several details of the fl...

Interaction of reed and resonator in reedorgan pipes without and with the resonator has been investigated. The wave form of the soundgenerated without the resonator attached is a periodic train (with the frequency of reed vibration) of decaying high frequency oscillation. The frequency of this oscillation is independent of the frequency of the reed...

The sound recordings of twelve pipe organs from four European countries (six Baroque, two Romantic and four contemporary) were subjectively evaluated. Two listening tests with sounds of tones C2, C3, C4, C5 and C6 of Principal 8' were provided. In the first test (dissimilarity in timbre in pairs of sounds) the spontaneously expressed verbal attribu...

Sound recordings of twelve pipe organs from four European countries (six Baroque, two Romantic and four contemporary) were subjectively evaluated. Principal sound contexts of Principal 8' (pitches C2, C3, C4, C5, and C6) were judged by twelve organ experts on dissimilarity in timbre. Perceptual space was constructed for each of the five tested soun...

The application of ears is one of the voicing techniques for flue organ pipes. The ears are the projections on both sides of the pipe mouth and have been used since the Renaissance period. They are frequently used to narrow scaled and low pitched pipes. By the structure around the mouth not only the radiation characteristics of the pipe but also th...

The aim of the investigations is the application of numerical methods for organ flue pipe research. The radiated sound of a flue pipe is very complex, affected by not only acoustical but also flow parameters. In order to reduce the problem complexity, a representative detail of the entire sound generating mechanism was selected, which can be numeri...

When basic phenomena of the physics of flue organ pipes are studied, experiments on models are acceptable. But frequently, these models differ considerably from real organ pipes. For this reason, the fine details of pipe sounds should be investigated on real pipes. The sound quality of an organ pipe is mainly influenced by the attack transients. Th...

Application of the ears to the flue organ pipe is one of the important voicing techniques. Ears are the projections on both sides of the pipe mouth. Organ builders say the ears make not only the sound lower and darker, but also the buildup of tone smoother and quicker. The aim of this research is to confirm their recognitions and make the causes cl...

Vibrations of plucked and blown reeds of lingual organ pipes without the resonators have been investigated. Three rather surprising phenomena are observed: the frequency of the reed plucked by hand is shifted upwards for large-amplitude plucking, the blown frequency is significantly higher than the plucked one, and peaks halfway between the harmoni...

Given certain design constraints, such as the type of stop being voiced and the desired tone quality,reed voicers must use consummate skill to curve each tongue so as to produce the best and most stable tone, as well as maintain a consistent tone quality across an entire rank of pipes. The curvature given to a reed tongue influences not only the ha...

This article is an over view of the characteristic sound properties of flue organ pipes. The characteristic properties of the stationary spectrum and attack transient have been surveyed and assigned to properties of the physical systems (air column as acoustic resonator, air jet as hydrodynamic oscillator and pipe wall as mechanical resonator) invo...

A special course on acoustics is organized regularly in the Fraunhofer‐Institute fr Bauphysik (IBP) for training pipe organ builders, official organ experts, and organists. The title of the 4‐day intensive course is ‘‘Pipe Organ and Church Acoustics’’ and it is scheduled at the end of January every year, when most of the organ builders are less occ...

No PDF available ABSTRACT For understanding the sound production of flue organ pipes, the acoustic properties of the two main components, the acoustic resonator and the air jet generator at the labium (flue + upper lip), have been investigated separately. It was found that the formant structure of the stationary sound spectrum is mostly determined...

The reed velocity and the sound pressure inside the shallot have been recorded in lingual organ pipes as the vibrating reed length is varied by means of the tuning wire (Stimmkrucke) (in an F3 trompette pipe, for example, the sounding frequency was varied from 157 to 325 Hz). Without the resonator, the frequency is a continuous function of the reed...

The influence of the wall vibrations on the timbre of flue organ pipes is one of the most disputed questions of organ building. Wall vibrations of metal and wooden labial pipes have been investigated by using miniature piezoelectric accelerometers and optical noncontact vibrometers. Both free and forced vibrations have been studied. Two sets of dia...

A continued fraction expansion to the immittances defining viscothermal wave propagation in a cylindrical tube has been presented recently in this journal, intended as a starting point for time domain numerical method design. Though the approximation has the great benefit of passivity, or positive realness under truncation, its convergence is slow...

Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies

The spatial fluctuations of sound fields are measured in reverberation chambers under the stimulus of noise and of tonal waves and the influence of rotating diffusers on the standard deviation is checked. In connection with this work the sound output and dynamic range of five violins using different playing techniques were investigated by means of...

The spatial fluctuations of sound fields are measured in reverberation chambers under the stimulus of noise and of tonal waves and the influence of rotating diffusers on the standard deviation is checked. In connection with this work the sound output and dynamic range of five violins using different playing techniques were investigated by means of...

The danger of terrorist attacks using toxic industrial chemicals (TICs) or chemical warfare agents (CWAs) has exposed the need for reliable and early detection of trace amounts of such compounds in the air. Sensors for airports, railroad stations, large public and private office buildings, etc. would be required for the early detection of CWAs and...

Coltman's experiment on the jet deflected by sound is re-examined numerically using computational fluid dynamical (CFD) simulation. The simulated jet is analyzed to obtain the phase delay and the magnitude of the deflection amplitude. A new jet deflection model is developed from these analyses. With this model, overblowing behavior of an organ flue...

In traditional organ building the very complex wind systems are the reason for the often unstable wind pressure. Large pressure drops and pressure fluctuations with high amplitudes may occur and affect the sound of the organ. To improve traditional wind systems and make their design more reliable twelve organ builder companies from nine European co...

Die Qualität einer Orgel ist abhängig von ihrer Anpassung an die akustischen Eigenschaften des Raumes. Sie kann über die Dimensionierungen der Pfeifen eingestellt werden. Heutzutage wird versucht die optimale Anpassung durch den Vergleich mit Orgelpfeifen in ähnlichen Räumen oder durch den Aufbau und Betrieb einer kleinen Windlade mit einigen Probe...

Durch das schnelle Aufheizen von Kirchen im Winter oder durch starke Sonneneinstrahlung im Sommer entstehen im Gehäuse zahlreicher Kirchenorgeln sehr ungleichmäßige Temperaturverteilungen, die zu störenden Verstimmungen im Orgelklang führen können. Nach einigen Voruntersuchungen in einer Klimakammer am Fraunhofer IBP zur Verstimmung einzelner Orgel...

The sound of an organ flue pipe originates from oscillation of an air jet in the mouth. The oscillation is caused by fluid dynamical instability of the jet itself and by sound generated in the flue pipe. The phase and magnitude of jet oscillation relative to sound is essential to determine which acoustic mode is excited as well as the spectrum of t...

Bei RLT-Anlagen mit überwiegend tieffrequentem Lärm kann es trotz Einhalt der Grenzwerte nach VDI 2081 zu Beschwerden kommen. Die Behbung einer solchen Situation durch Nachrüstung ist stets kostspielig und unter Umständen unmöglich. Ziel des Vorhabens ist die Erweiterung der bestehenden akustischen Auslegungsmethoden hinsichtlich Ortstabhängigkeit...

Kurze Familiengeschichte der Orgelbaufamilie Angster bezogen auf den Orgelbau.

Investing in research is foreign to most organbuilders. The pipe organ is a traditional instrument, for which it is natural to think that everything has already been invented. An experimental session was called in April 2009 at the Fraunhofer Institute in Stuttgart. The participants spent two solid days investigating a number of metal pipes special...