Rindik rod sound separation with spectral subtraction method

Abstract

Rindik is a traditional music instrument originated from Bali that consists of 11 bamboo rods and played by a person hitting the bamboo rod with a rubber mallet in each player’s hands. Documentation of Rindik songs with automatic music transcription work is easier to do by separating it first. To overcome that challenge, two Rindik rods sound were separated using the spectral subtraction method. The noise spectrum is the spectrum of a single rod sound that needs to be muffled. The resulting audio is the other single rod sound and vice versa to get both single rod sound. The data consisted of single rod hit sound recordings of 11 single rod sound and 55 combinations of two-rods sounds being hit at the same time. The performance of the spectral subtraction method in separating Rindik sound was measured with MSE and SIR and also heard the noise exists in the separated audio signal. The experiment demonstrated a state-of-the-art performance consists of spectral subtraction with squared noise average magnitude with average MSE value 0.0126 and average SIR value 55.68 dB.

Wavelet Transformation and Spectral Subtraction Method in Performing Automated Rindik Song Transcription

“…DFT has a complexity of O(n 2 ), while calculations with FFT only have a complexity of O(n log n) [25]. The equation of the DFT is written in equation (1).…”

“…DFT is a function of k in the frequency domain. Each function of k is an impulse function with a magnitude, frequency, and phase shift [1]. In this study an iterative and separation estimation approach will be used and the Figure 8 and 9 is a flowchart of the implementation of the approach.…”

“…Because spectral subtraction works in the frequency domain, a Fourier transform is performed first with a fast Fourier transform (FFT) for each frame. After obtaining the frequency domain of the signal, the average magnitude of the noise spectrum will be calculated and squared [1] with the (2) formula.…”

“…Rindik is one of the traditional musical instruments originating from Bali [1]. Rindik is a musical instrument made of several bamboo rods that are arranged horizontally and played by hitting it with two mallets in each player's hand called "panggul" [2].…”

“…One of the signal subtraction approaches that have been carried out in previous studies is spectral subtraction [14]. In a study conducted by Christian and Darmawan, spectral subtraction was used to separate the sound of 2 Rindik rods that being hit simultaneously resulting an average MSE (mean squared error) of 0.0126 and a SIR (signal to interference ratio) of 55.68 dB [1]. In this study, the first pitch estimation for one segment of the rod hit was carried out and the Rindik tone with the nearest frequency to be used as noise in the spectral subtraction process.…”