Passive 8" Portable Two-Way Utility Stage Monitor and Loudspeaker System The STI PS 8 is a portable, eight-inch, two-way speaker system designed for either main sound reinforcement or monitoring applications. It is perfect for speech reinforcement of any type, live performance stage monitoring, reinforcement of vocal and acoustic music, and as a high-performance satellite speaker for use with subwoofers. PS passive speakers were designed to provide the sensitivity, frequency response and power handling needed for almost any professional audio environment while still being reasonably priced. Whether you use a powered mixer or an equipment rack full of amps and signal processing, PS passive speakers deliver the sound power and bandwidth necessary to make loud music sound natural and even quiet speech intelligible.