PreSonus E66 Overview The Eris E66 Active MTM Series Nearfield Monitor from PreSonus delivers an expanded and highly accurate frequency response and a wide stereo field. Its nested Midwoofer-Tweeter-Midwoofer (MTM) configuration offers improved off-axis response and spatial resolution. The result is a more consistent listening experience, smoother frequency response, and an ultra-wide, detailed stereo soundstage. Conventional 2-way designs can cause significant early reflections from their surrounding environment. The E66 overcomes this by positioning a 1.25", silk dome high-frequency driver between two 6.5" midrange drivers. The two smaller woofers work in parallel to partially contain the dispersion of the tweeter, minimizing phase displacement. The result is detailed stereo imaging. The E66 features two midrange drivers that cover the same frequency range. The drivers are placed so that their acoustic centers are less than one wavelength apart for any of the frequencies they reproduce. This results in the combined signal of both drivers propagating forward like a single waveform. This makes the comparatively small midrange drivers in the E66 behave like a single, larger driver. This mutual coupling provides a highly dynamic output in a compact footprint. Sound waves radiating from the two components in a conventional speaker design can interfere with one another, creating peaks at some frequencies and dips at others, and these will vary depending on where the listener is relative to the speaker. In an MTM configuration, component interference, and the sonic inconsistencies that go with it, are minimized. This affords listeners an ultra-wide sweet spot and a more consistent listening experience on- and off-axis. The E66 utilizes custom-woven Kevlar low-frequency drivers. This provides a more constant dispersion pattern throughout the frequency range, resulting in less time-smeared audio and cleaner overall sound. The weave and nature of the dual Kevlar woofers also helps break up reflected energy, so fewer delayed reflections reach the listener's ear. In conjunction with the MTM configuration, this works to create a transparent, cohesive sound. Many MTM configurations must be arrayed vertically, rather than horizontally, because vertical placement provides a clear, interference-free midrange and treble reproduction to either side, expanding the sweet spot. By bringing the midrange drivers closer together and raising the high-frequency driver, the E66 is able to perform optimally in both orientations. This studio monitor offers acoustic tuning controls, including a three-position Acoustic Space switch that helps compensate for the boundary bass boost that can occur when a monitor is placed in a corner or near a wall. High and Mid controls help to further mitigate room anomalies. A Low Cutoff filter makes it easy to integrate a Temblor subwoofer into your monitor setup. With three different types of audio inputs, it's easy to feed audio to your Eris monitor from a mixer, an interface, a media player, or almost any other line-level source. The E66 provides balanced XLR, balanced 1/4" TRS, and unbalanced RCA line-level inputs. Components and Construction Dual 6.5", custom-woven Kevlar LF/midrange drivers 1.25", silk-dome HF driver ensures smooth high-frequency performance Balanced XLR, balanced 1/4" TRS, and unbalanced RCA inputs provide flexibility User Controls Acoustic tuning controls help to compensate for room anomalies, providing a consistent frequency response Continuously variable HF and MF controls (-6 to +6 dB) Low-cut filter (flat, 80 Hz, 100 Hz) Acoustic Space settings (Flat, -2 dB, -4 dB) compensates for room placement Power and Safety 90/140 W Class A/B bi-amplification for an open, clear sound RF interference, output-current limiting, over-temperature, and subsonic filter protection Amplifier soft start feature eliminates popping on power-up Internal power supply with IEC connector