Acoustic Analysis and Mathematical Modelling of a Stiff Spring-Coupled Double-String Banam: A Study of Vibrational Characteristics

Indian musical instruments, such as the Banam, combine strings with a resonating membrane. In this study, we investigate the acoustic properties of the Banam musical in-strument. Initially, the Banam is played, and the resulting audio signal is recorded using an audio recorder. The recorded signal is plotted, and its frequency content is analysed using the Short-Time Fourier Transform (STFT) rather than the Fast Fourier Transform (FFT) to capture its time-varying characteristics. The power spectrum and spectrogram are used to investigate the energy distribution across frequencies and the variation in frequency con-tent over time, respectively. The power spectrum indicates that the signal contains more energy at lower frequencies than at higher frequencies, which is consistent with the spec-trogram, where prominent dark bands appear in the lower-frequency region. Furthermore, a mathematical model of the Banam, represented as a coupled two-string system connected by a bridge, is developed to investigate its natural frequencies and their variation.