Presonus Eris Active Speakers Eris professional studio monitors by PreSonus use quality components, are well constructed, and deliver professional audio quality. They deliver accurate response, tight bass, and clear upper endThey're also lightweight and compact, and look as professional as they sound. PreSonus offer small, medium, and large Eris-series monitors: the E4.5, E5, and E8. All Eris speakers feature Kevlar® low frequency transducers, low-mass silk-dome tweeters, and responsive Class AB amplification. The ultra-compact and potable E4.5 has a 4.5-inch low-frequency driver and a 25W Class AB amplifier that gives it plenty of juice. The next step up in size and power is the E5, which sports a 5.25-inch low-frequency driver and a 45W Class AB amplifier. For an extended low-frequency response and a bit more muscle, step up to the Eris E8. With its 8-inch low-frequency driver and 75 watt, Class AB power amplifier, the E8 can range down to 35 Hz, but still reach the high frequencies