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Assessment Effects of Humidification of Guitars by Complexity Measures of the Sound Level During Sustain

100%

Stępień R. , Wrzeciono P.

Archives of Acoustics

2024

tom Vol. 49, nr 2

189--197

Air humidity significantly affects the sound of wooden instruments. The sound quality decreases when the instrument is exposed to low humidity for an extended period. Therefore, the instrument is treated with a humidifier to improve sound quality. This study aimed to verify the effectiveness of the humidification process by analyzing the quality of guitar sound with the methods used in signal complexity studies, such as Higuchi’s fractal dimension (HFD), symbolic analysis, and empirical mode decomposition (EMD). The sound quality was determined by the sound levels measured before, during, and after the guitars’ humidification. The methods used consistently confirmed the improvement of the guitar sound quality after the humidification process. Moreover, it was concluded that the sound quality changes irregularly during the humidification process.

Problem of placing the organ pipes on the windchest

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Węgrzyn D. , Wrzeciono P.

tom Vol. 30, nr 1

art. no. 2019121

This paper presents research showing the problem occurring in the construction of a pipe organ, related to the placement of the organ pipes on the windchest. The close location of the organ pipes to each other influences the parameters of the sound generated by the pipes. It causes an intonation problem, namely the detuning of the organ pipes if they are located too close to each other on the windchest. The presented measurements show the influence of a distance between pipes of various types on basic sound parameters, such as frequency or volume level. The research carried out shows that in extreme cases the detuning reaches a temperate halftone. This has undoubtedly an impact on the tuning of organ pipes, especially in the case of a table organ or pipe organ built in a small space. In the future, the outcomes of the presented research can be applied in the windchest design.

Measurement of the surface reflectance of an acoustic wave using wave packets propagating in a circular waveguide

100%

Wrzeciono P. , Szymański M.

Vibrations in Physical Systems

2022

tom Vol. 33, nr 2

art. no. 2022218

The main idea of the measurement presented in this paper was to separate the incident wave from the reflected wave. For this purpose, short wave packets and a sufficiently long waveguide with a circular cross-section were used. Several types of wave packets were developed and used in the experiment. We found that a wave packet of 5 ms duration could be propagated in a waveguide of length 5.6 meters without significant sound level losses. We used an audio interface operating at a sampling rate of 96 kHz in the measurements. The limit of wave propagation without dispersion phenomenon was determined. The developed measurement methodology made it possible to maintain the same air temperature along the entire length of the tested waveguide since short pulses did not cause the speaker temperature to rise. Avoiding this effect reduced the measurement uncertainty of the reflection coefficient.

Automatic Indexer for Polish Agricultural Texts

100%

Karwowski W. , Wrzeciono P.

Information Systems in Management

2014

tom 3

nr 4

229-238

Today, the majority of resources are available in digital forms to acquire information. We have to search through collections of documents. In this paper text indexing which can improve searching is described. Next, indexing tool, the Agrotagger, which is useful for documents in the field of agriculture, is presented. Two available versions of the Agrotagger are tested and discussed. The Agrotagger is useful only for the English language despite the fact that it uses multilingual thesaurus Agrovoc. Because of the Agrotagger is not useful for texts in Polish, it is important to create similar tool appropriate for the Polish language. The problems connected with extensive inflection in languages such as Polish language in the process of indexing were discussed. In the final part of the paper, it is presented design and implementation of a system, based on the Polish language dictionary and the Agrovoc. Additionally some tests of implemented system are discussed.