In this study, multimodal acquisition and bandwidth broadening are enhanced by employing multimodal spread spectrum theory to establish a versatile piezoelectric vibration-energy acquisition system. The system comprises two modules-an energy collector and a power-management circuit. The collector operates across four resonant frequencies, thus ensuring efficient energy harvesting in low-frequency vibration settings. The power-management circuit converts AC power into stable DC power for charging energy-storage components. Following modal-harmony response analysis, an experimental platform is constructed for system testing. Experimental results indicate an operational frequency band of 16.1 to 27.8 Hz, with a peak output voltage of 33.75 V under a simple harmonic force and an acceleration of 6 m/s2. Upon impedance matching, the optimal resistance value is shown to be 200 kΩ, which results in an output power of 115.85 μW.