This paper presents a driving scheme for silicon opto-acoustic oscillators (OAO) by simultaneously exploiting radiation-pressure (RP) and RF feedback oscillation mechanisms to achieve significantly lower phase noise than could be realized by either phenomenon solely. A theoretical model and experimental results are presented corroborating this scheme, demonstrating a silicon OAO operating at 175 MHz with a phase noise of −128.6 dBc/Hz at 1 MHz offset with 2.77 dBm RF output power, resulting in a 10dB far-from-carrier phase noise improvement.