Magnetostrictive-piezoelectric composite in bi-layer structure shows a resonant enhancement for the mechanical strain mediated magnetoelectric coupling when operating under bending mode. Such composite is of importance to achieve ultrasensitive magnetometers for detecting quasi-static magnetic fields by measuring the parameter variation near the resonant frequency. Detection performance is limited by diverse noise processes appearing in the composite and associated electronics such as the extrinsic interferences due to the environmental vibration and temperature and loss noise sources produced by the energy dissipation in the composite. Since the bending resonance is based on the mechanical interactions in the composite, the noise source due to the thermo-mechanical dissipation becomes an importance noise process to be investigated. In this paper, we investigate the field detection performance relating to the thermo-mechanical and thermo-electric dissipation in a doubly clamped magnetoelectric composite by means of modulation techniques.