András Miklós

Universität Heidelberg

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...

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 aim of this work was to evaluate the emission of nitrous oxide (N2O) using a diesel engine at laboratory scale without a catalytic converter with diesel/biodiesel blends (%) of 95:5 (B5), 90:10 (B10), 85:15 (B15), 80:20 (B20), 75:25 (B25), and 50:50 (B50). Measurements of N2O in the exhaust gas were made using an experimental setup based on pho...

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...

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...

The present work shows the application of the photoacoustic spectrometer in the monitoring of the ethylene emission rate in passion fruit submitted to different types of atmosphere storage. Three types of modified atmosphere were applied: 1) 100% N2 and 0% O2 (MA1), 2) 97% N2 and 3% O2 (MA2) and 3) 94% N2 and 6% O2 (MA3). The respiratory rate and p...

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...

A Brazilian sedimentary zeolite-containing microporous material was characterized by determining its physical and chemical properties (surface area, pore volume, dinitrogen and ammonia desorption rates, oxide composition, and acid site characterization), and compared with two commercial natural zeolites. The characterization of these materials was...

In this work we present a laser photoacoustic ar- rangement for the detection of the important greenhouse gas methane. A quantum-cascade laser and a differential pho- toacoustic cell were employed. A detection limit of 45 ppbv in nitrogen was achieved as well as a great selectivity. The same methodology was also tested in the detection of methane i...

This work addresses the effects of ozone activity on the physiology of 'Golden' papaya fruit. Depth profile analysis of double-layer biological samples was accomplished using the phase-resolved photoacoustic spectroscopy. The feasibility of the method was demonstrated by singling out the spectra of the cuticle and the pigment layers of papaya fruit...

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...

The increase in greenhouse gas emissions is a serious environmental problem and has stimulated the scientific community to pay attention to the need for detection and monitoring of gases released into the atmosphere. an almost non-reactive gas widely employed in industrial processes worldwide. Indeed it is estimated that it has a radiative forcing...

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...

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...

Photoacoustic (PA) spectra generated by current modulation of a distributed feedback diode laser (DFB-DL) were measured for the ammonia absorption line at 1.53 microm and calculated using absorption spectra taken from a database. The algorithm is based on a combined amplitude- and wavelength-modulation (AM-WM) scheme. The spectral characteristics o...

We report the first results obtained with a Brazilian sedimentary zeolite (hereafter called the zeolite concentrate, ZC) to reduce ammonia volatilization – loss of the nitrogen nutrient – in tropical farms. Preliminary laboratory tests were made with both ammonium sulfate and urea into ZC. The reported field tests – obtained in rose cultivation...

Selective and sensitive detection of formaldehyde (CH2O) was achieved using a grazing-incidence optical parametric oscillator (GIOPO), pumped at high repetition rate, as a light source for photoacoustic spectroscopy. The photoacoustic spectrum of formaldehyde was measured in the range from 2785 to 2840cm-1 and an absorption line at 2805.0cm-1 was s...

Pulsed quantum cascade lasers (QCLs) with 6.2-μm and 8-μm wavelengths and a differential photoacoustic (PA) detector were used to measure concentrations of NO2 and N2O in the sub-ppmv range at ambient pressure. The QCL temperatures were tuned between -40 °C and 30 °C. Good agreement was found between measured PA vibrational spectra and simulated HI...

A pulsed quantum-cascade distributed-feedback laser, temperature tunable from -41 degrees C to +31.6 degrees C, and a resonant differential photoacoustic detector are used to measure trace-gas concentrations to as low as 66 parts per 10(9) by volume (ppbv) ammonia at a low laser power of 2 mW. Good agreement between the experimental spectrum and th...

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...

What we believe to be a novel multipass, acoustically open photoacoustic detector designed for fast-response, high-sensitivity detection of trace gases and pollutants in the atmosphere is demonstrated. The acoustic pulses generated by the absorption of the light pulses of a tunable optical parametric oscillator by target molecules are detected by a...

Photoacoustic spectroscopy, in combination with a pulsed grazing-incidence optical parametric oscillator (GIOPO), was used for sensitive detection of nitrous oxide (N2O) in ambient air. The ν1+ν3 combination band of N2O was excited with the idler beam of the GIOPO in the 2.76 μm–2.91 μm spectral region, where CO2 and water-absorption lines are also...

A compact pulsed optical parametric oscillator operated in an optical cavity with a grazing-incidence grating configuration was used to demonstrate sensitive photoacoustic detection of trace quantities of ethylene (C2H4). An IR wavelength within the absorption band of ethylene that produces minimal signal interference by background gases was identi...

Nitrous oxide (N$_2$O) concentrations in ambient air were measured by photoacoustic spectroscopy. The light source, a grazing-incidence optical parametric oscillator (GIOPO) with a periodically-poled lithium niobate (PPLN) crystal, was pumped by a pulsed Nd:YAG laser. Measurements were performed in the spectral region of 2.76-2.91 $\mu$m containing...

A wavelength-amplitude (WM-AM) double-modulation technique that uses the acoustic wave generated via light absorption by a gaseous medium as the carrier wave is demonstrated. By modulating the excitation wavelength of the light pulses from a multi-kHz optical parametric oscillator at a lower frequency than the acoustic frequency, differential infra...

An acoustically open photoacoutic sensor designed for high sensitivity detection of trace gases and pollutants in the atmosphere is demonstrated. The detection sensitivity is ∼3×10-9Wcm-1

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...

With a laser-excited acoustic wave as the carrier wave and by modulation of the light wavelength of a multikilohertz-repetition-rate optical parametric oscillator at a lower frequency than the acoustic frequency, we demonstrate a wavelength-amplitude double-modulation technique and achieve an enhancement factor of 35 in sensitivity in photoacoustic...

A 9.5-m pulsed quantum cascade laser (QCL) and a differential photoacoustic (PA) detector were used to measure trace concentrations of 100ppbv ozone at ambient pressure with high selectivity. The QCL was tuned by temperature variation between -41C and 30.6C and the corresponding wavelengths were determined by the PA spectrum of CO2. Good agreement...

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...

. A pulsed optical parametric oscillator (OPO) operated in an optical cavity with a grazing-incidence grating configuration (GIOPO) was used for sensitive photoacoustic detection of trace quantities of dinitrogen oxide (N2O). The (ν1+ν3) combination vibration band of N2O was excited with the idler beam of the GIOPO at 2.86 μm using an optical cavit...

A pulsed periodically poled lithium niobate optical parametric oscillator operating in a cavity with a grazing-incidence grating configuration was used for sensitive and precise measurement of trace quantities of methane in nitrogen by photoacoustic spectroscopy with a novel differential photoacoustic detector. A sensitivity of 1.2 parts in 10(9) b...

Sensitive photoacoustic detection of ammonia with near-infrared diode lasers (1.53 microns) and a novel differential acoustic resonator is described; a sensitivity of 0.2 parts per million volume (signal-to-noise ratio = 1) is attained. To eliminate adsorption-desorption processes of the polar NH3 molecules, a relatively high gas flow of 300 SCCM w...

A distributed-feedback (DFB) diode laser radiating at 1.53 mum was used for photoacoustic detection of ammonia molecules in the gas phase under flow conditions. The influence of the adsorption-desorption processes that occur at the cell and tube walls on the measured gas concentration was studied. Dramatic differences in the adsorption behavior of...

The application of different types of acoustic resonators such as pipes, cylinders, and spheres in photoacoustics is considered. This includes a discussion of the fundamental properties of these resonant cavities. Modulated and pulsed laser excitation of acoustic modes is discussed. The theoretical and practical aspects of high- Q and low-Q resonat...

Photoacoustic trace gas detection was demonstrated using pulsed grazing-incidence periodically poled lithium niobate optical parametric oscillator (OPO) used in photoacoustic spectroscopy (PAS). Methane was used as the sample gas and its detection was performed in nitrogen and ambient air. The concentration of methane in air was found to be 1.84 pp...

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...

Photoacoustic spectroscopy (PAS) can be considered a form of optical spectroscopy and a form of calorimetry. Andras Miklos and Peter Hess of the University of Heidelberg (Germany) discuss the current state of PAS and its prospects for the future.