The PreSonus Eris E66 is the larger of two models in the company’s MTM Series of active studio monitors. MTM refers to the configuration of drivers on the front panel where two mid-frequency woofers (the “M”s in the series name) symmetrically flank a tweeter (the “T”). This is also known as the “D’Appolito arrangement,” named for its creator, Joseph D’Appolito.
Properly implemented, MTM improves coherence between the individual drivers, smooths out the off-axis response, and provides detailed stereo imaging. The Eris E66 driver complement consists of a pair of 6.5-inch drivers with Kevlar cones and a 1.25-inch silk-dome tweeter protected by a robust metal screen. Onboard amplifiers deliver 80 watts to the mid-woofers and 65 watts to the tweeter, enabling the Eris E66 to achieve maximum SPLs of 106 dB: That should be more than enough for anyone with common sense.
One of the Eris E66’s attractions is that it works equally well whether placed horizontally or vertically. When they are placed vertically, PreSonus suggests that the tweeters be located on the outside, forming a mirror-image pair with a small footprint (which is how I used them). The illuminated PreSonus logo serves as a power-on indicator and may be easily rotated so that it can be read correctly regardless of placement.
The rear panel includes switches for tuning the monitor's frequency response to your own studio environment. The rear panel of the Eris E66 provides unbalanced RCA and balanced TRS and XLR jacks, with a trim pot to accommodate a variety of input levels. (For the review, it was set to unity.) The remaining rear-panel controls tailor the Eris E66’s response within the listening environment. The High Frequency trim provides 6 dB of boost or cut using a 10kHz shelf, and the Mid control offers 6 dB of boost or cut with a peaking curve centered at 1 kHz. The Low Cutoff switch has positions for Flat plus 80 Hz and 100 Hz, both of which engage a filter with a slope of -12 dB per octave. The Acoustic Space switch compensates for the bass boost that occurs when a monitor is placed near a wall or corner by reducing the level of frequencies below 800 Hz by 2 or 4 dB: It is defeated when set to 0 dB. Also on the rear panel are an IEC power receptacle, the power switch, and a voltage selector.
During the course of my experience with the Eris E66, all of the rear-panel switches and trim controls remained at 0, as I did not feel the need to use them. (More on that in a moment.) The speakers were arranged vertically, with tweeters on the outside per PreSonus’ recommendation, and set atop my monitor stands in the usual position approximately 14 inches from the front wall. Each monitor was pointed slightly in toward the listening position, which is also normal in my control room.
My first impressions listening to the Eris E66s were that they provided clarity in the midrange, good imaging, and a tight bottom end. But the results of my first mixes made on these monitors were puzzling. When heard on other systems, the mixes produced too much low end, as if someone had tilted the bass response up a few dB. The quality of the bass was excellent but it was just too loud. I felt that the other aspects of the mixes were accurate—no surprises in balance between instruments, judgment of timbre (the aforementioned excepted), or ambience.
Back at the studio I listened to the same mixes again and the bottom end sounded fine. I checked the contour controls to make sure they were flat (they were). I mixed several more songs and experienced similar results. Mind you, it was pleasant, but I did not feel it was consistent with my experience in this control room over the past 20-plus years.
If the Eris E66 had a low boost control, I would have bumped the bottom up 3 dB. That would enable me to hear more bass in the control room and mix accordingly. But the E66 does not have any provision to boost the low end, only to cut it. This slight skew in the low frequency response may be acceptable to many people. I considered the idea of moving the monitors closer to the front wall, which would undoubtedly increase the low end, but I don’t think we should have to rearrange our control rooms to accommodate new monitors.
In spite of the growing pains I experienced, ultimately adjusting to the Eris E66s was easy: My mixes traveled well, as long as I acknowledged that I should hear a bit less bottom in the control room. It was easy to get the mix right from the mids up, and the Eris E66s otherwise prompted me toward good decisions. I have no logical explanation for the bass response of these monitors other than the possibility that, for some reason, the Eris E66 did not play well with my control room.
Overall, the Eris E66 has many strengths, but I would recommend an audition in your own control room before making a purchase.
Excellent midrange reproduction. Solid imaging. Controlled dispersion reduces unwanted reflections.
Didn’t play well in the low end with my control room.
Steve La Cerra is an independent audio engineer based in New York. In addition to being an Electronic Musician contributor, he mixes front-of-house for Blue Öyster Cult and teaches audio at Mercy College, Dobbs Ferry campus.