Mechanical modelling of the frequency response of a vinyl audio turntable : comparison with digital music formats

• Main Author: Eu, Beng Hui.
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics
• Online Access: http://hdl.handle.net/10356/53949
• Institution: Nanyang Technological University

This project serves to investigate how the frequency spectrum of vinyl music, specifically stereophonic vinyl Long Play records played at a speed of 331⁄3 rpm on a 12-inch disc, compares to that of high-temporal-resolution digital music. We have developed an electromechanical model for the frequency response and noise characteristics of a vinyl record player. The model incorporates mechanical resonances arising from the properties of the record player’s tonearm and stylus, and of the elastic surface of the vinyl record. The model also incorporates the electrical response of the circuitry leading to the input of the system’s amplifier. We have used this model to simulate the sound of four music tracks as if they were played on a vinyl record player. The simulations take high-temporal- resolution digital music tracks, modify their frequency content and superimpose simulated noise. These simulations can form the basis of a comparison with sound captured from actual vinyl recordings of the same four tracks. The model and simulations are implemented using MATLAB. Bode plots of the transfer functions of the models of key components of the record player aid in understanding how their poles and zeros affect the frequency response. By comparing true vinyl track, simulated vinyl tracks and digital tracks, we hope to understand how the frequency response of a vinyl system might cause some people to favour the sound of vinyl over the portability of digital music.