Contents of issue 1, vol. 31 (2006)

  1. R.J. Panuszka, K.A. Panuszka, Frank Lloyd Wright's Samara, acoustical solutions of the 1950's, Archives of Acoustics, 31, 1, 3-16
  2. L. Majkut, Acoustical diagnostics of cracks in beam like structures, Archives of Acoustics, 31, 1, 17-28
  3. D. Kutzner, Modelling the sound envelope auditory processing using the non-negative-impulse-response modulation filters concept. Part I. Initial simulations, Archives of Acoustics, 31, 1, 29-45
  4. P. Pękala, Comparison of the cone-tracing simulation and the room impulse response measurements, Archives of Acoustics, 31, 1, 47-56
  5. A. Snakowska, H. Idczak, The saddle point method applied to selected problems of acoustics, Archives of Acoustics, 31, 1, 57-76
  6. L. Leniowska, Effect of active vibration control of a circular plate on sound radiation, Archives of Acoustics, 31, 1, 77-87
  7. W. Ciesielka, A. Gołaś, Active control of sound by means of digital equalizers, Archives of Acoustics, 31, 1, 89-97
  8. E. Zieniuk, K. Szerszeń, A solution of 3D Helmholtz equation for boundary geometry modeled by Coons patches using the Parametric Integral Equation System, Archives of Acoustics, 31, 1, 99-111
  9. Technical Notes

  10. P.H.T. Zannin, J.A.C. Ferreira, Evaluation of performance of acoustic materials - a case study in Brazilian civil construction, Archives of Acoustics, 31, 1, 113-119
  11. Chronicle, 35-th Winter School on Wave and Quantum Acoustics, Archives of Acoustics, 31, 1, 121-142
  12. Chronicle, 34-th Winter School on Vibroacoustical Hazards Suppression, Archives of Acoustics, 31, 1, 143-149
Archives of Acoustics, 31, 1, 3-16

R.J. Panuszka*, K.A. Panuszka**, Frank Lloyd Wright's Samara, acoustical solutions of the 1950's
*AGH University of Science and Technology
Al. Mickiewicza 30, 30-059 Kraków, Poland
e-mail: panuszka@localline.com
**Acoustical Consulting
Lafayette IN 47904, USA
e-mail: kpanuszka@purdue.edu
(received April 30, 2005; accepted October 25, 2005)
The problem of environmental noise pollution concerns many Americans whose homes are near highways and busy streets. A famous American Architect, Frank Lloyd Wright, designed houses that have been noted for their architectural splendor and alleged acoustical superiority over more traditional designs. Mr. Wright's acoustical knowledge was tested by taking acoustical measurements and comparisons of traffic noise transferred from the adjacent highway (U S State Route 231). The sample home was a Usonian home and two traditionally designed houses located adjacent to Mr. Wright's design. Noise levels were significantly lower in the Usonian home (called SAMARA by Mr. Wright) compared to the traditionally designed houses. A difference of about 10 dBA existed due to Mr. Wright's unique architectural design. Significant design concepts contributing to this reduction included the excavation depth of the house, screening by the carport, and screening by other natural screens like wintergreen trees and shrubs.
Key words: architect, Frank Lloyd Wright, Usonian, Samara, acoustics, noise.

Archives of Acoustics, 31, 1, 17-28

L. Majkut, Acoustical diagnostics of cracks in beam like structures
AGH University of Science and Technology
Al. Mickiewicza 30, 30-059 Kraków, Poland
e-mail: majkut@agh.edu.pl
(received April 30, 2005; accepted October 25, 2005)
In this paper, the acoustical symptoms of a constructional element with an edge non-propagating crack on the example of a cantilever beam are searched. In this work the influence of a crack on flexural natural frequency was analysed. The crack is substituted by a rotational spring, which flexibility is calculated using the Castigliano theorem and the laws of the fracture mechanics.
In this work the changes in the first and second natural frequency of the flexural vibrations are showed as a function of location and depth of the crack. The acoustic signal measured with a microphone placed above the beam is used for diagnostic systems.
Changes in the natural frequency cannot be used for the identification of a small crack (the depth is less than 10% of beam height). For the detecting of a smaller crack, the effect of coupled different modes of vibration is presented. The paper presents a modelling and analysis algorithm for cracked Euler-Bernoulli beams by considering the coupling between the bending and axial vibration modes. The analysis of the coupled vibrations showed that additional resonance frequencies appeared in the acoustic spectrum.
Key words: acoustical diagnostic, crack, crack detection, vibration, coupled vibration.

Archives of Acoustics, 31, 1, 29-45

D. Kutzner, Modelling the sound envelope auditory processing using the non-negative-impulse-response modulation filters concept. Part I. Initial simulations
Adam Mickiewicz University, Institute of Acoustics
Department of Room Acoustics and Psychoacoustics
Umultowska 85, 61-614 Poznań, Poland
e-mail: konsbol@wp.pl
(received May 25, 2005; accepted December 9, 2005)
This article concerns with a new model of the sound envelope processing in the auditory system. The so-called non-negative-impulse-response (NNIR) modulation filters concept argues that if any form of the acoustic signal envelope filtering took place in the auditory pathway, this process should not be described in terms of a band-pass filtration. This modification of the traditional model of the auditory system temporal resolution, based on the modulation filterbank (MFB) activity, results from the cardinal property of the sound envelope and its neural representation, i.e. neural discharges period histogram, which are unavoidably unipolar signals of non-negative values. It has been assumed that if hypothetical modulation filters existed, they should be characterised by a non-negative-impulse-response and, consequently, the frequency characteristics of such filters might not reveal the band-pass properties. The results of the model investigations are compared with selected psychophysical and physiological data.
Key words: amplitude modulation, the Hilbert transform, modulation filterbank, impulse response, variance.

Archives of Acoustics, 31, 1, 47-56

P. Pękala, Comparison of the cone-tracing simulation and the room impulse response measurements
Adam Mickiewicz University, Institute of Acoustics
Umultowska 85, 61-614 Poznań, Poland
e-mail: ppekala@amu.edu.pl
(received March 2, 2005; accepted December 9, 2005)
The experimental verification of the acoustic field model based on the cone-tracing method [1, 2] is described. With simulated echograms and the impulse responses obtained experimentally, a set of parameters: Early Decay Time (EDT), C50 and C80 were obtained. The parameters measured at many receiving sites and those calculated were compared. Mean differences of less than 2 dB were observed for the octave band mid-frequencies above 125 Hz.
Key words: cone-tracing modelling, sound field optimisation, measurement verification.

Archives of Acoustics, 31, 1, 57-76

A. Snakowska*, H. Idczak**, The saddle point method applied to selected problems of acoustics
*University of Rzeszów, Institute of Physics
Rejtana 16a, 35-310 Rzeszów, Poland
e-mail: asnak@univ.rzeszow.pl
**Wrocław University of Technology, Institute of Telecommunication and Acoustics
Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
e-mail: henryk@zakus.ita.pwr.wroc.pl
(received July 11, 2005; accepted December 9, 2005)
The paper is aimed at the presentation of examples of applying the saddle point approximation method to some fundamental problems of acoustics and the discussion of some interesting couplings between applied mathematical methods and the physical interpretation of the results.
The saddle point method is shortly reminded in its basic form, from which more advanced versions, improving the results and widening the range of possible applications, are derived. Two problems, solved at first for electromagnetic waves and then applied to acoustics by means of ``the analogous method'', have been chosen as examples. The first one is the phenomenon of the reflection of a spherical wave at a plane interface between two media, the lower of which is characterised by a higher velocity (water/sand, air/water). In this case there is a critical angle above which a total reflection and a lateral wave occur. The second example is the far field radiated from the outlet of a semi-infinite circular duct. The physical insight into the understanding of the physical phenomena provided by the saddle point method is stressed.
Key words: saddle point method, waves propagation in layered media, lateral wave, radiation from cylindrical duct.

Archives of Acoustics, 31, 1, 77-87

L. Leniowska, Effect of active vibration control of a circular plate on sound radiation
University of Rzeszów, Institute of Technology
Rejtana 16a, 35-310 Rzeszów, Poland
e-mail: lleniow@atena.univ.rzeszow.pl
(received April 30, 2005; accepted October 23, 2005)
An active control of the vibration cancellation of a circular fluid-loaded plate is analytically studied. The purpose of this paper is to examine the effect of the active vibration control strategy on the sound radiation generated by a plate. It was assumed that a planar vibrating structure located in a finite baffle and interacting with fluid is driven by a periodic force with constant amplitude. This structure radiates the acoustic waves into a surrounding fluid and a point control force is used to reduce its vibrations. The simulations of the active cancellation of the plate vibrations were made with a Simulink/Matlab computer program. The results demonstrate, that while a control law provided a significant reduction in the plate vibration, it is rather ineffective for noise attenuation.
Key words: vibration control, sound radiation, circular plate, LQR controller.

Archives of Acoustics, 31, 1, 89-97

W. Ciesielka, A. Gołaś, Active control of sound by means of digital equalizers
AGH University of Science and Technology
Department of Mechanics and Vibroacoustics
Al. Mickiewicza 30, 30-059 Kraków, Poland
e-mail: ghciesie@cyf-kr.edu.pl, ghgolas@cyf-kr.edu.pl
(received April 30, 2005; accepted October 25, 2005)
The article describes single-channel digital systems, enabling active sound control according to the set criterion. Theoretical fundamentals of these systems are based on digital filter theory, using which the digital graphic, phase, inverse and adaptive equalizers have been designed and programmed. The described systems have been implemented into two cards with signal processors TMS320C25 and TMS320C31 made by Texas Instruments. The article presents mathematical models of the above mentioned equalizers and results of the experimental tests, which verify their performance.
Key words: active sound control, digital equalizer.

Archives of Acoustics, 31, 1, 99-111

E. Zieniuk, K. Szerszeń, A solution of 3D Helmholtz equation for boundary geometry modeled by Coons patches using the Parametric Integral Equation System
University of Białystok, Department of Mathematics and Physics
Institute of Computer Science
Sosnowa 64, 15-887 Białystok, Poland
e-mail: ezieniuk@ii.uwb.edu.pl, kszerszen@ii.uwb.edu.pl\\[3mm] (received April 30, 2005; accepted October 25, 2005)
In this paper, the authors propose an algorithm for numerical solution of the 3D Helmholtz equation using the Parametric Integral Equation System (PIES). The PIES, unlike the traditional Boundary Integral Equation (BIE), is characterized by the fact that the boundary geometry has been considered in its mathematical formalism. Polygonal Coons surfaces have been used to describe the 3D domain. This makes it possible to obtain continuous solutions without any discretization of the 3D domain.
Key words: Helmholtz equation, Boundary Integral Equation (BIE), Parametric Integral Equation System (PIES).

Archives of Acoustics, 31, 1, 113-119

Technical Notes
P.H.T. Zannin, J.A.C. Ferreira, Evaluation of performance of acoustic materials - a case study in Brazilian civil construction
Universidade Federal do Paraná - Departamento de Engenharia Mecânica
Laboratório de Acústica Ambiental - Industrial e Conforto Acústico
Centro Politécnico - Bairro Jardim das Américas
CEP: 81.531-990 - Curitiba - PR - Brasil\\ e-mail: zannin@demec.ufpr.br
(received November 15, 2004; accepted August 18, 2005)
Urban noises are emitted simultaneously by a wide variety of sources, such as, transportation and activities encountered in large cities. Many studies show that traffic noise followed by noise produced by neighbours are the main disturbing sources. Considering that both traffic and neighbour noise upset people inside their homes, it is possible to conclude that these homes do not display good performance of one of their purposes, which is the one of providing acoustic comfort. This fact is critical in Brazilian homes, as opposed to countries such as Germany and the USA, since these countries have specific rules for acoustic properties of materials used in civil construction, and Brazil does not. The goal of the present study is to show the acoustic performance of materials routinely used in Brazilian civil construction. Measurement procedures both in situ and in the laboratory are presented to determine acoustic performance of the materials, such as: insulation coefficient for air propagation. The results have shown that the acoustic performance of Brazilian constructions, are under international standard.
Key words: sound insulation, acoustic comfort, civil construction, urban noise, insulation coefficient.

Archives of Acoustics, 31, 1, 121-142

Chronicle, 35-th Winter School on Wave and Quantum Acoustics
Ustroń, 27-th February - 3-rd March 2006
I have a great pleasure to give the "Archives of Acoustics" Readers possibility acquaint with topics presented at 35-th Winter School on Wave and Quantum Acoustics. This School, organized by Upper Silesian Division of the Polish Acoustical Society and Institute of Physics at Silesian University of Technology, is planned at February/March 2006 in beautiful scenery of Silesian Beskidy Mountains.
As always, the School has been a place where achievements of various sections of acoustics (especially molecular acoustics, quantum acoustics, acousto-optics, magnetoacoustics, acoustoelectronics, photoacoustics, acoustics of solids etc.) are being exchanged. Moreover, some similar and related topics, for example optoelectronics and thermal wave methods, will be presented too.
For the second time the School will be divided on three different, but complementary, parts - Winter Workshops (WW). Chronologically it will be: 2-nd WW on Acoustoelectronics and Optoelectronics (chairman: prof. Tadeusz Pustelny), 2-nd WW on Molecular and Quantum Acoustics (chairwoman: dr Marzena Dzida) and 11-th WW on Photoacoustics and Thermal Waves Methods (chairman: prof. Jerzy Bodzenta). This dividing was very well accepted by Participants.
After acceptation by revivers the School lectures will be published in one of two journals - in Journal de Physique IV - Proceedings (which is published by EDP Sciences and covered in the ISI database) or in Journal of Molecular and Quantum Acoustics (annual journal published by Upper Silesian Division of the Polish Acoustical Society). Moreover, all Participants will obtain a folder with Program of the School and full set of the one page abstracts obtained by organizers.
Once again we have taken pains to organize this conference taking into account the fact that it is an important event for acousticians, opticians and other Polish and foreign scientists. We hope that this reach conference program will gain acceptance and respect among its potential participants. We count on your numerous response and active participation.
In behalf of Organizers: Roman Bukowski, coordinator of the School

Archives of Acoustics, 31, 1, 143-149

Chronicle, 34-th Winter School on Vibroacoustical Hazards Suppression
Ustroń, 27-th February - 3-th March 2006
I invite you to acquaint with abstracts of selected lectures submitted to presentation in 34-th Winter School on Vibroacoustical Hazards Suppressions. This national School, organized by Upper Silesian Division of the Polish Acoustical Society and Institute of Physics at Silesian University of Technology, is planned at February/March 2006 in Ustroń.
The conference is the forum for all environmental vibroacoustics fields. Particularly it concern to traffic noise, industry noise, vibroacoustics of machines, room acoustics, noise protection and similar problems. During the School the theoretical works, experimental, measuring, technical, applied and normative ones are presented.
The School lectures, and other conference materials, will be published in the "Materials of the XXXIV Winter School on Vibroacoustical Hazards Suppressions" edited by dr. Mieczysław Roczniak (chairman of the conference). This publication is intend to participants of the School and for many libraries in Poland.
Other information about XXXIV WS on VHS you can find at address http://gnom.matfiz.polsl.gliwice.pl/zzw/zzw_06/.
In behalf of Organizers: Roman Bukowski, coordinator of the School