Sound recording archives contain valuable audio information of scientific and cultural significance, but face immediate threats of deterioration. This study combines chemical and audio analyses to investigate the impact of scratches, prevalent defects on audio cassette tapes, on sound quality. Additionally, it aims to establish a parameter system for objectively evaluating changes in audio quality resulting from such defects. Both uniform and non-uniform scratch simulation samples with varying degrees of scratching were prepared. Morphological changes associated with scratches are assessed using Scanning Electron Microscopy (SEM). Macroscopic morphological data is obtained through gray-level histogram analysis of scanner images. Surface roughness is analyzed using Laser Confocal Scanning Microscopy. Finally, Praat software is utilized to evaluate how different levels of scratching affect wideband spectrograms as well as various aspects such as audio intensity and frequency relationships. This research provides novel insights into understanding magnetic archives while offering theoretical references for future restoration efforts.
Yu et al. (Wed,) studied this question.