Yet such hybrids often turn out to be mules, in my experience, their sounds remaining resolutely earthbound. To integrate drivers with very diverse radiation patterns—the omnidirectional woofer and the bipolar panel—sets the speaker engineer a pretty…
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Combine an electrostatic panel to reproduce music's midrange and treble with a moving-coil woofer for the bass foundation. For decades, this has seemed the ideal way of designing a loudspeaker: Each type of drive-unit is used in the frequency region for which its performance is optimized. The resulting hybrid should sing like an angel.
Like all electrostatic speakers, the Aerius needs to be energized from a wall AC outlet. An AC lead plugs into an IEC receptacle on the speaker's rear, all the power-supply circuitry being internal so that the speaker can be manufactured to be country-specific in terms of line frequency and voltage. Given that makers of laptop computers use universal power supplies that will work anywhere in the world without adaptors, this would seem to be a backward step. However, MartinLogan does this, I believe, to cope with the increasing amount of "gray-market" sales afflicting the international High…
I suspected from my experience with pink noise that this reticent top octave is also exacerbated by some peakiness lower in frequency, in the mid-treble. Though it was not generally sibilant, the Aerius did indeed add some slight emphasis to tape and microphone hiss. Close-miked soprano voice also took on a hard edge as it got higher in level. And the trumpets in my Elgar Dream of Gerontius recording on the second Stereophile Test CD had a little too much brassy blattiness. Changing from the YBA to the Mark Levinson No.20.6 monoblocks softened the mid-treble. This change also added an octave…
Which brings me to the Aeriuses' soundstaging. Recorded ambience, indeed, seemed more obvious, with longer decays, than I had expected from listening to the same tracks on conventional speakers. The differences between the various artificial reverberation programs Corey Greenberg had used on his "Eden" track on Test CD 2 seemed larger than I had thought. And instruments didn't move forward or backward in the stage as they were played louder or softer.
Soundstaging was generally well-focused, with no tendency for images to pull to the center. But I didn't get much of a sense of the stage…
Sidebar 1: Specifications
Description: Two-way, floorstanding loudspeaker. Drive-units: 37.5" H by 7.5" W electrostatic panel, 8" (203mm) pulp-cone woofer in sealed enclosure. Crossover frequency: 500Hz. Crossover slopes: second-order, 12dB/octave. Frequency response: 40Hz-20kHz !X3dB. Dispersion: 30 degrees horizontal, 38" line source vertical. Sensitivity: 89dB/W/m (2.83V). Nominal impedance: 4 ohms. Minimum impedance: greater than 2 ohms at 20kHz. Amplifier requirements: 60-200W.
Dimensions: 55.5" (1410mm) H by 10.5" (267mm) W by 13.5" (343mm) D. Weight: 55 lbs (25kg) each.
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Sidebar 2: If You Can't Wait...
To sum up the MartinLogan's pluses: looks the business; sets the soul of music free; works well in small rooms near the rear wall; superb integration between the disparate drive-units; seamless overall balance; transparent, timbre-true midrange; well-extended, well-defined lows; excellent depth and retrieval of recorded ambience; costs less than Wilson WATTs/Puppies; not for Red Hot Chili Peppers fans.
Minuses: mid-treble has tendency to glare at high levels; high treble shelved down; tape hiss accentuated; won't go very loud without strain; unkind…
Sidebar 3: Measurements
As can be seen from its impedance plot (fig.1), the Aerius is considerably easier to drive than its larger sibling, the Quest Z (reviewed by Dick Olsher elsewhere in this issue). Yes, it does drop to 1.7 ohms above the audio band—the cursor position—but the phase angle in this region is close to 0 degrees; if you don't use an MC cartridge with a vicious tip-mass resonance or you only listen to CD, the amplifier won't be asked to do any work in this region. And lower in frequency, where the bulk of musical energy lies, the Aerius's impedance magnitude stays above 5…
The panel's output is less easy to interpret. The top octave is shelved down, while the mid- and low-treble are broken up by peaks and notches which may be due to resonances, or to interference effects specific to the particular microphone position chosen. The peak at 420Hz and the suckout just above that frequency might be at least partly due to the nearfield microphone technique. The panel can be seen to roll out very quickly below 300Hz, however.
Looking at how these two responses integrate at a 45" distance, fig.5 shows the quasi-anechoic response averaged across a 30-degree…
Returning to the time domain, fig.8 is the cumulative spectral-decay, or "waterfall," plot calculated from the Aerius's impulse response (fig.2). This appears much cleaner in the midrange than that of the Quest Z, presumably because the well-behaved dynamic woofer is taken two octaves higher in frequency. The high treble is similarly hashy, however, while the low- and mid-trebles feature a number of resonant ridges.
Fig.8 MartinLogan Aerius, cumulative spectral-decay plot at 45" (0.15ms risetime).
As I explain in the Quest Z review, this kind of waterfall behavior is…
Sidebar 4: Sam Tellig on the Aerius i
(From July 1997, Vo.20 No.7)
(From July 1997, Vo.20 No.7)
"Can we have these?"
Such was my wife Marina's reaction to the MartinLogan Aerius i loudspeakers as soon as I'd set them up in the living room. I had to agree: they do look elegant, especially with black side panels—almost like Japanese screens. The speakers stand nearly 5' high (55½"), and 10½" wide by 12½" deep. Small footprint.
"Of course," Marina hastened to add, "that's if you think the speakers sound good."
"What do you think?"
"I think they sound as good as they look."
No…