This paper describes the acoustic measurement of the sub-scale booster and launch pad. The 1:42 scale solid propellant booster was settled over the launch pad model on a flat plate. Designed to deflect the hot and high speed jet plume, the launch pad model was expected to mitigate acoustic impact fed back toward the vehicle. The launch pad model plays a role in attenuating the sound due to the impingement of the plume and the deflector. To investigate the acoustic field with a different booster height, acoustic measurement was carried out. The measurement involved the conventional acoustic measurement and the sound source localization. The conventional measurement employed the near-field microphones around the booster model and the far-field microphones on an arc centered on the base of the launch pad. In the sound source localization, a phased array microphone system was settled to focus the deflector exit. The obtained acoustic data helped revise the design of the launch pad model.