Pengolahan Sinyal Akustik Untuk Mengukur Koefisien Absorpsi

Muchajjaliin, Yusron (2025) Pengolahan Sinyal Akustik Untuk Mengukur Koefisien Absorpsi. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini bertujuan untuk mengoptimalkan proses pengukuran koefisien absorpsi akustik dari suatu material menggunakan metode tabung impedansi dua mikrofon. Proses pengolahan sinyal dilakukan secara sistematis, diawali dengan akuisisi sinyal white noise dalam domain waktu yang kemudian diubah ke domain frekuensi menggunakan Fast Fourier Transform (FFT). Fungsi transfer akustik (H), yang memuat informasi amplitudo dan fase, diestimasi secara valid menggunakan Metode Welch. Fungsi transfer ini kemudian digabungkan dengan parameter geometri dari setup eksperimen untuk menghitung koefisien refleksi (R) sesuai standar ISO 10534-2:1998, dan pada akhirnya nilai koefisien absorpsi (α) diperoleh. Pengujian dilakukan pada rentang frekuensi 50-1600 Hz dengan empat variasi konfigurasi jarak mikrofon yaitu 1-5; 2-5; 3-5; 4-5, posisi mikrofon juga saling ditukar pada saat melakukan pengukuran pada setiap konfigurasi. Hasil penelitian menunjukkan bahwa nilai koefisien absorpsi sangat dipengaruhi oleh konfigurasi jarak mikrofon. Nilai absorpsi yang didapat berdasarkan puncak tertinggi berurutan dari konfigurasi 1-5; 1-5swap; 2-5; 2-5swap; 3-5; 3-5swap; 4-5; 4-5swap adalah 0,9986; 0,9821; 0,6559; 0,6388; 0,9378; 0,9757; 0,9871; 0,9930.
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This research aims to optimize the measurement process of a material's acoustic absorption coefficient using the two-microphone impedance tube method. The signal processing is conducted systematically, beginning with the acquisition of a white noise signal in the time domain, which is then converted to the frequency domain using the Fast Fourier Transform (FFT). The acoustic transfer function (H), which contains amplitude and phase information, is validly estimated using Welch's Method. This transfer function is then combined with the geometric parameters of the experimental setup to calculate the reflection coefficient (R) according to the ISO 10534-2:1998 standard, from which the absorption coefficient (α) is ultimately obtained. The test was performed in the 50-1600 Hz frequency range with four variations of microphone distance configurations: 1-5; 2-5; 3-5; and 4-5. The microphone positions were also swapped during the measurement for each configuration. The results indicate that the absorption coefficient value is highly influenced by the microphone distance configuration. The absorption values based on peak in the graphic obtained sequentially from the 1-5; 1-5swap; 2-5; 2-5swap; 3-5; 3-5swap; 4-5; and 4-5swap configurations are 0,9986; 0,9821; 0,6559; 0,6388; 0,9378; 0,9757; 0,9871, and 0,9930.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	FFT, Fungsi Transfer, Koefisien Absorpsi, Pengolahan Sinyal, Tabung Impedansi Absorption Coefficient, FFT, Impedance Tube, Signal Processing, Transfer Function
Subjects:	Q Science Q Science > QC Physics > QC221 Acoustics. Sound
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Physics > 45201-(S1) Undergraduate Thesis
Depositing User:	Yusron Muchajjaliin
Date Deposited:	04 Aug 2025 03:34
Last Modified:	04 Aug 2025 03:34
URI:	http://repository.its.ac.id/id/eprint/125452

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