Product Review - Martin Logan Aerius i Hybrid Electrostatic Speakers - May, 2000


Joseph Caraciolo

Introduction 

Electrostatic speakers (ESLs) have always been a very romantic look to have in a Home Theater, and one of the most recognizable electrostatics are those manufactured by Martin Logan. Most of Martin Logan's current speaker line is high quality hybrid electrostatic loudspeakers, that is, speakers that incorporate both a large electrostatic panel and one or more traditional cone woofers. This is done because bass reproduction requires a lot of air movement, and an electrostatic panel able to move enough bass to produce the lowest octave would have to be huge. By incorporating a traditional bass driver, Martin Logan's speakers are able to fit in tight spots and small apartments.

In the case of the Aerius i, only one square foot of floor space is lost to speaker bulkiness, and at a list price of $2,300, they may be worth making room for. The Aerius i's stature is not very deep, but they make up for it in height. At a towering 56 inches (with spikes), they could easily be the dominant piece of any home theater system. Most of the bulk is dedicated to the electrostatic panel, which measures 9" x 40" and is slightly curved outward into the listening area like a half-moon. The other 16 inches house a traditional 8" woofer in a sealed chamber. The speakers are available with a variety of wood side rails to help integrate them into the listening environment, yet the Aerius i's are no chameleon.

Over the process of my review, I had about ten people visit my home theater, and each had a different opinion about the ML look. Some thought they were attractive, and some thought they were an eyesore. I think they are beautiful but would recommend taking a serious look at them for yourself before purchasing.

The back panel is simple enough: two pairs of binding posts allow for bi-wiring, while a simple detachable power cord supplies AC electricity to the panel. On the bottom are three screw holes for floor risers (which I found to be necessary) or carpet spikes. The front looks like one giant electrostatic panel, but the bottom third is simply the woofer's grill. The rails framing the front of the speaker are easily replaceable, so even if you didn't get those Natural Cherry side rails to begin with, they can be purchased later.

Setup

I found that the Aerius i's to be a very picky speaker where they are placed. Although proper calibration is a necessity for good sound with any loudspeaker, the MLs require three times the effort just to accomplish bearable sound. Because of the dipole nature of the electrostatic panel, the environment and positioning must be well prepared, for them to perform optimally. To this effect, Martin Logan produces a 23-page owner's manual with about half the content devoted to speaker positioning and environment. The manual includes recommendations for floor and wall types, acoustical wall treatment, distance from side and rear walls, distance from each other, distance from the listening position, and on and on.

If you want a speaker that fits in almost any spot, no matter how sonically unforgiving, the MLs are not for you (nor are any ESLs for that matter). I placed the Aerius in my normal position for Home Theater, which is about a foot from the side and rear wall and 8 feet from each other with the TV at the median. The sound was terrible. Imaging was unfocused, there were too many early reflections, the soundstage was practically on the floor, and I couldn't find a sweet spot. So I moved them away from both walls (and consequently closer to each other), adjusted the supplied risers to raise the front edge up about an inch, and placed some diffusers on the wall directly behind them. A vast improvement, but still not quite there.

Overall it took me about a week to get them properly situated. With each change, I would adjust something (the wall material, the riser height, and the toe-in angle), listen, and then readjust until I was finally satisfied.

Sound

I tried the Aerius i with a Yamaha DSP-A1 and a Rotel RB-986MKII both rated at 110 watts per channel. I was worried, because Martin Logan speakers have a tendency to present an amplifier with a very low impedance, but there were no problems with that regard. Although the speakers are not overly efficient (89 dB sensitivity), I think that both amplifiers were able to drive them adequately. What I found was that the Aerius have a very sweet sound, and with proper adjustment, offered a wide soundstage. The midrange specifically was very natural and offered no harshness at any volume. The 8" driver was fast and able to keep up with the electrostatic driver even during quick transients. 

Martin Logan's choice of crossover frequency yielded a seamless transition between the bass driver and the ESL panel. My only gripe about this hybrid design has to do with the woofer being placed close to the floor. Because sounds are still very localizable down around the 300 Hz area, some voices sounded strangely misplaced. I didn't dare adjust the risers to compensate for this problem, as doing so may have muddied the entire upper range.

The bass response is listed by Martin Logan to have a -3cdB point of 40 Hz, but with my AudioControl Real Time Spectrum Analyzer, I found that they offered plenty of bass in the 30 Hz area, but barely touched below that. This is not to say the Aerius don't need a subwoofer because, to cover the entire audible range, a sub is necessary.

I auditioned the speakers with a variety of music types, as I am aware of the rumor that electrostatic loudspeakers have a hard time reproducing hard rock music (loud). I first tried them with the recently released "Rage Against The Machine" album, "The Battle of Los Angeles" and quickly dismissed the rumor. The Aerius have a certain presence that I don't hear from many other speakers. This was mostly due to the midrange clarity and very laid back (yet detailed) treble that made the performers sound like they were in the room.

Coupled with a subwoofer and a steep 24 dB per octave crossover at 80 Hz, the midrange simply came alive. I was very impressed, as the electrostatic panels have no harshness associated with traditional tweeters (especially metal ones), and this translated into very detailed highs. On much of the Jazz material I listened to, the cymbals were soothing and had depth to them. Many high hat subtleties are lost to treble distortion or limited dynamics in conventional speakers, but the Aerius performed superbly. Imaging was very focused in the sweet spot, creating a nice center image between the speakers.

With orchestral recordings, I could place many of the performers and found that the Aerius favored the violins. Mozart's Requiem (Phillips) placed them just left of center, while vocals were nicely spread across the entire front soundstage. But the further away from center I moved, the more I noticed the "beaming" which is characteristic of all ESLs to a certain degree. I also found that the center image collapsed into the speakers when I sat close to them.

Experiments with movie listening pointed out that the Aerius would make a very good home theater speaker. Even coupled with a direct radiating center channel speaker, the Aerius were able to perform without betraying their positions. However, Martin Logan does offer an ESL center channel speaker.

With "Phantom" mode engaged, I could hear the very soft and clear distinction that these speakers offered. They do not clutter up on-screen voices with any added depth or coarseness. Because of the Aerius' midrange strength, voices sounded very clear, and very natural. They were neither overly forward nor withdrawn, but simply there, on screen. It was nice to hear such a flat reproduction that is so true to the recording.

All Good Things . . .

Finally it was time to return the Martin Logan Aerius i ESLs. Although I was very happy with the sound, the picky nature and massive stature are not compatible with my apartment-changing lifestyle. I will miss them though, especially the midrange, and would recommend them to anyone who has the patience to play with them, and an environment designed for them. These speakers deserve a trip to your local Martin Logan dealer for a listen. Who knows, maybe you'll be seduced by their natural sound like I was.

- Joseph Caraciolo -

© Copyright 2000 Secrets of Home Theater & High Fidelity
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