As a technology that allows sound to be heard only in specific areas in public spaces, the directional sound of parametric speakers has been attracting attention. The parametric speaker is also expected to have a wide range of uses, in settings ranging from shopping malls to museums for presenting information sound. The purpose of this study is to measure evaluate the Speech Recognition Threshold (SRT) of parametric speakers and compare with that of loudspeakers at various noise levels through experiments. It can also reveal how much the parametric speaker can reduce the noise heard by non-target users, which is unavoidable with loudspeakers.Through experiments, the volume required to transmit an informative sound to a particular listener is about 12.61 dBA less than the level necessary for the loudspeaker. Moreover, the SRT of the surrounding people is about 2.48 dBA higher than that for the loudspeaker. Based on the results, the volume received by people in the surrounding area, including environmental noise, was calculated, and the effect of noise reduction is discussed. This study provides important insights for the flexibility in the design of the sound space.