Viscothermal effects at the walls are dominant sources of loss in air columns various types wind instruments. The classical theory viscous and thermal boundary layers gives an analytical result that allows for computing wall losses acoustical wave propagation cylindrical ducts. Based on theoretical considerations, a simple formula is derived straight ducts taking shape cross section into account coefficient. This unidimensional model compared to three-dimensional finite element computations...

The process of selecting the geometrical dimensions pipes in a pipe organ is referred to as scaling.Wooden with rectangular cross-section are usually designed so that their cross-sectional area equals corresponding cylindrical pipe.It often occurs, especially case lower registers, wooden rank does not fit into available width, and necessarily made narrower.In this case, maintaining crosssectional same may result significant change timbre due increased amount wall losses.This paper proposes...

In order to investigate the physical processes involved in build-up of sound signal a labial organ pipe foot model has been developed. The main important parameters, such as positions lower and upper lips, wind pressure foot, width flue, can be adjusted by means this model. Moreover, different types languids bodies (resonators) attached For reason corresponding real metal these parts are made typical alloy used building. reproducibility measurements is provided micrometer screws applied for...

The effect of tuning slots on the sound characteristics labial organ pipes is investigated in this paper by means laboratory experiments. Besides changing pitch pipe, slot also plays an important role forming timbre. objectives contribution are to document influence built with different geometries pipe and validate observed tendencies reproducible It found that measured steady state spectra show unique characteristics, typical only for pipes. By separately adjusting geometrical parameters...

An optimization method, based on an acoustic waveguide model of chimney and resonator, was developed tested by laboratory measurements experimental pipes. The dimensions the pipes are modified algorithm until specified fundamental frequency is achieved, a predetermined harmonic partial overlaps with eigenfrequency pipe. were dimensioned method for four different scenarios built organ builder. show excellent agreement between measured sound spectra calculated input admittances. can be used design

Vibrations of plucked and blown reeds lingual organ pipes without the resonators have been investigated. Three rather surprising phenomena are observed: frequency reed by hand is shifted upwards for large-amplitude plucking, significantly higher than one, peaks halfway between harmonics fundamental appear in spectrum velocity. The dependence on length reveals that vibrating at small vibrations 3 mm shorter apparent free length. shift plucking explained periodic change during oscillation....

Interaction of reed and resonator in organ pipes without with the has been investigated. The wave form sound generated attached is a periodic train (with frequency vibration) decaying high oscillation. this oscillation independent vibration; it corresponds roughly to fundamental acoustic resonance shallot. Another rather surprising phenomenon was also observed: pipe resonator, vibration frequency, correspondingly continuous function vibrating length, but when added “forbidden” domains occur...

A three-dimensional coupled vibroacoustic finite element model for physics-based simulations of the sound generation by mallet percussion instruments in time domain is discussed present paper. The mechanical takes orthotropic material properties wooden bars and nonlinear nature interaction force between head bar into account while acoustical considers radiation an unbounded domain. direct coupling bars, cavity resonators, excitation a considered with exploiting modal basis to reduce number...

An acoustic model suitable for the characterization of tuning slots labial organ pipes is presented in this paper. Since slot arrangement similar (but not identical) to that toneholes woodwind instruments, adaptability well-established tonehole specific problem examined. A numerical utilizing finite element (FE) and perfectly matched layer techniques set up simulation with design parameters varying over a wide range. Analytical models proposed are both combined analytical one-dimensional...

In the sound spectrum of flue organ pipes in addition to usual harmonic partials, sometimes a series equidistant but not lines can be found. This phenomenon has been observed recorded from different pipe ranks. The second set spectral is similar “frequency combs” used optics for accurate measurement optical frequencies. Analysis measured spectra with and without frequency comb simulations are presented discussed paper. appearance combs explained by model that assumes presence mouth tone...

Although organ flue pipes have been widely studied, the same claim cannot be made for pipe reed stops. Given certain design constraints, such as type of stop being voiced and desired tone quality, voicer must use consummate skill to curve tongue so produce best most stable well guarantee that each blends with its neighbors. The amount given a influences not only harmonic structure steady-state sound but also attack. There are two fundamentally different types curvature can tongue, trompette...

Within the framework of a European research project exciting new results have been achieved recently in lingual organ pipes. The main objectives are to solve practical problems dimensioning reed pipes, develop innovative methods and software for helping sound design work builder enterprises. A better understanding role shallot resonator on attack timbre pipes is necessary this reason. Visualization motion by high speed camera measurements velocity, wind pressure boot shallot, at end revealed...

The principle of the sound power measurements carried out in anechoic chamber and reverberation room is shortly described paper.The advantages disadvantages both methods practice some results musical instruments are shown.

The reed velocity and the sound pressure inside shallot have been recorded in lingual organ pipes as vibrating length is varied by means of tuning wire (Stimmkrücke) (in an F3 trompette pipe, for example, sounding frequency was from 157 to 325 Hz). Without resonator, a continuous function length, but when conical resonator added, pipe jumps abruptly below above each resonance sonator. When natural (excited plucking) 138 316 Hz changing its changed 170 340 Hz. Reed closure may induce strong...

Abstract Bei vielen Kirchenorgeln machen sich im Winter Verstimmungen Orgelklang bemerkbar. Vor Spielbeginn wird die Kirche in relativ kurzer Zeit aufgeheizt. Zum einen entstehen dadurch innerhalb des Orgelgehäuses verschiedene Temperaturzonen, zum anderen werden bereits erwärmter Umgebung befindenden Orgelpfeifen mit Luft aus dem noch kalten Windsystem gespeist. Um den Einfluss Einblasens von kalter eine Orgelpfeife auf deren Verstimmung zu untersuchen, wurde Labor Fraunhofer‐Instituts für...

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 voicer. Nevertheless zinc much cost-efficient. Grillo Werke (Germany) developed a “soft strip” which significantly better, as far workability concerned, than materials available in past. This tested to determine what extent modifies pipe wall vibrations, and how essential impact would be on sound. Various pairs...

The sound characteristics of both labial and lingual organ pipes are affected to a great extent by the reflection properties resonators. In this paper, sloped pipe terminations examined possible applications in building practice investigated. Sloped shallots reed with different termination angles particular interest study. For examination two approaches applied. Sound pulse measurements on model geometries provide experimental data time domain, while finite element simulations yield...