HS4 4.5-inch powered studio monitors (52 W, 4.5-inch woofer and 1-inch dome tweeter, 60 Hz-22 kHz per price list). Yamaha HS Series speakers are the standard in studio monitors, trusted for many years by top audio engineers, producers and artists; the HS3 and HS4 bring that legacy to a compact housing for creators with limited space who do not want to compromise on monitoring quality. Inside are a high-performance class-D amplifier (one amp driving both speakers), a highly resilient MDF cabinet, and woofers and soft-dome tweeters that deliver a pure sound faithful to the source, while the proprietary Twisted Flare Port delivers clear bass with minimal turbulence noise. Rear-panel ROOM CONTROL and HIGH TRIM adjust the sound to the environment, and inputs include combination XLR/TRS phone, RCA and stereo mini connectors for computers, interfaces, mixers and instruments. Power button, volume knob and headphone connector are located on the front. Sold as a pair.