MartinLogan Monolith loudspeaker:
Page 2 Each Monolith has external strapping which makes bi-amping (and bypassing of the internal crossover components) relatively simple. I used an M&K 100Hz passive crossover to feed the BEL for the high end and the Eagle at the bottom. There ws some improvement in quality across the board, but not as much of an improvement through the lower midrange and upper bass as I had hoped for. The low end remained rather ill-defined and still had what I felt to be entirely too much high end, but biamping produced the best sound up to that point in my testing.

Equalization
A phone conversation with ML'S Gayle Sanders revealed that I was not the first person to complain about the Monolith's brightness. Indeed, ML was already making available a passive equalizer that could be connected to the electrostatic element (via the back-panel strapping) to tame the aggressive upper range. Gayle offered to send me a pair of them.

Each equalizer consists of an inductor, resistor and capacitor, all paralleled and connected in series with the signal line. The effect of this network is to depress the range above 4kHz, with a flattening-out shelf above 8kHz (to prevent progressive attenuation of the extreme upper range). I won't say this transformed the speakers, but it sure put them in the right ballpark.

Extreme highs were still a little excessive, but the apparent brightness of the speakers now corresponded pretty well with the known attributes of the amplifiers used on the high end. (The Eagle, for example, is somewhat bright, which is one reason it makes so many speaker systems sound almost shockingly real and alive.) With the equalizer in, the high end from the Eagle/Monolith combination corresponded well to the qualities of the various program sources. The grittiness I had previously noted was entirely gone and, with the best available source material the Eagle/Monolith's high end sounded as palpably real as anything I have heard. HF detailing was so incredible that the sound would have been totally unlistenable had I been using a preamp with the slightest tendency toward harshness or grittiness. (I was using a tubed preamp known to have an unusually sweet, clean high end—the Conrad Johnson PV-5).

Yet, while this sound was tremendously exciting, it did not have quite the effortless ease that makes live music so easy to listen to. For that quality I must keep returning to the Watkins WE-1s (footnote 3).

By comparison, the BEL amplifier sounded sweeter and more "listenable," but some of that reach-out-and-touch-someone aliveness had been lost. With the Paolis, the extreme high end was right on, but the middle high-end brightness was once again excessive. (I like less high-end content than do most audiophiles who frequently complain that live music is lacking in treble. I should also add that I feel that most loudspeakers have entirely too much HF output; I am not singling out the Monolith for this criticism.)

Imaging
One thing that remained consistently superb throughout the testing was the Monoliths' imaging. To hear electrostatic-type detail, smoothness, and attack, without the usual on-axis sizzle and off-axis dullness and imaging deterioration, was a rare privilege. What this means in terms of stereo imaging has to be experienced to be believed! The Monoliths image almost as well as any system I have ever heard, and is even capable of the remarkable holographic effects I have previously heard only from a couple of satellite systems. (By "holographic" I refer to the impression that closely miked sounds are located out in front of the speakers, floating spookily in space a few apparent feet in front of my face.) The soundstage is wide and deep, and front-to-back perspectives replicate those of the recordings themselves about as well as I have heard from any speaker system.

Interestingly, though, while the Monolith has no high-end directivity, it does have some in the middle range. To either side of the speaker's "axis" the sound loses some of its body and impact, and if the speakers are not toed-in towards the center of the listening area there is a significant shift in lateral image position as one moves from side to side. There are speakers which provide more uniform lateral localization from a wider listening area, but all of these have a "shaped" directivity pattern in which the apparent output from each driver diminishes as you approach a location directly in front of it. (The dbx "Soundfield" speaker is a prime example of this directivity shaping.) But, all in all, the imaging from the Monoliths is as good as I have heard from any other kind of speaker, particularly any electrostatics.

That's where things stood—lots of potential, but not the overall satisfaction you should get for this kind of money when Electron Kinetics' John Iverson paid me a visit, carrying a cute little new Eagle amplifier under one arn. (Try to do that with the 7A!) It was an Eagle 2, rated at 120Wpc and priced, at that time, at $850. (It has since risen to $895.)

Revelations
We tried the new Eagle with the Monoliths (which were back to being mono-amped), and I was flabbergasted to hear this little amp dramatically outperform its big brother in every way. The low end was much tighter and suddenly had real concussive impact from kick drum. The high end was sweeter, more open, and more musically euphonic, and the entire audio range had superior detail. The sound of good recordings was astoundingly alive—and except for that lower middle range deficiency—was far better than anything I had ever previously heard in my own listening room! I was really bowled over, and after several months of living with this system, I still am. I won't go as far as to say this is the best sound reproduction I have heard anywhere, but in most respects it comes close.

But what, then, is the "sound" of the ML Monoliths? On the basis of what I know about the sound of the amplifiers I used with it, I'd say it is (with the "equalizer" noted above) extraordinarily detailed, a little bright and forward (although not hard, with the right power amp), somewhat uppish at the high end, and very extended but still a shade woolly at the bottom.

ML's assurances notwithstanding, this system does benefit from tube amplification (using an external passive crossover). The low end is tighter, deeper, and better-controlled, and the rest of the range is slightly but definitely cleaner and detailed.

The speaker's high-end sound with the BEL amp suggested that some amplifiers do not need the equalizer. The Threshold or Krell amps may turn out to be just the ticket, but after having lived with the Monolith/Eagle combination (with the equalizers) for a while, I have decided that that is, at least as of now, my preferred combination. I like this combination better in some respects (imaging, depth, deep-bass range, extreme high end, and aliveness) than the Eagle/Watkins pairing, but still find the latter more convincing in its portrayal of large brasses, cellos, and piano bass strings.

One thing which energ.d clearly from my tests is that the Monoliths are both unusually amplifier-sensitive and amplifier-critical.

These are not necessarily the same thing. The speakers are amplifier-sensitive in that their low-end control is drastically affected by the power amp used. They seem to need something with tremendous LF current capability in order to sound respectably disciplined at the low end. They are amplifier-critical in that their incredib1e detail and slight brightness make them exceedingly revealing of the merest traces of distortion in the power amp and preamp.

There are probably so few power amps out there that meet both criteria that I could only recommend the speakers with some strong qualifications or with specific amplifier recommendations. And I haven't tried enough amps yet to be able to recommend at this point any but the Eagle 2 or MartinLogan's suggested Threshold Stasis units. (Although I would guess the big Krells or the new Rowland Research amps might do fine too. We have a Rowland on hand, and I'll report in the next issue on how it goes with the Monoliths. The Krell amps are still with Antony H. Cordesman on the East Coast, so I don't know when I'll be able to comment on their abilities with the Monoliths.)

In short, the MartinLogan Monolith is yet another example of the truism that nothing is perfect. This system images so well, and has such hair-raising dynamic range, definition, and clarity (through most of its range) that its small imperfections seem less forgivable. It's rather like going to heaven and finding that it's everything you expected except that it never stops raining!

Some of the Monolith's shortcomings could, I think, be easily eliminated by some more creative equalization. I would, for example, like MartinLogan's HF equalizer to do just a little more of what it does now. And I know some hyping of the 300–800Hz range would enhance the speaker's ability to reproduce the large brasses, cellos, and so on. If it doesn't measure flat then, who care? After all, we keep telling ourselves, the "bottom line" in audio is how something sounds, not how it measures.

The low-end 1ooseness with many amps may be harder to remedy. This is, as I said, only a minor problem with the Eagle 2, but was really bad with some other power amps. Some of this is, I believe, related to the subjective shortage of mid- and lower-midrange contribution, but that's clearly not the whole story on the Monolith's low end. I suspect it is also caused by the system's 6dB/octave crossover, which allows the woofer to operate well up in the lower midrange before dropping out of earshot. (MartinLogan is currently working on a powered woofer system with integrated amplifier—see my editorial in Vol.7 No.5) that should effect a marked improvement in bass quality.)

Summing Up
There are so many things I love about the Monolith that I hate to qualify my review of it. One could argue that the degree to which it does practically all of the right things is probably worth the $4850/pair price, but the fact remains that there are some areas where its performance will not be up to what most buyers would expect from a speaker in this price class. There is just no point in trying to pretend that the Monolith will be all things to all listeners.

The add-on equalizer, which I feel should be made available without additional charge to the buyer (or, better still, incorporated into the speaker's internal crossover), is a step in the right direcfion. I hope there will be more such steps, and I shall watch further developments at MartinLogan with great interest.

J. Gordon Holt returned to the Monolith in March 1986 (Vol.9 No.3):
While I (currently) favor the MartinLogan Monoliths because of their incredible you-are-there realism, I still go back to the Infinity RS-1Bs from time to time for their awesome quality of power and excitement. The Infinities can give me goosebumps more often than any other speakers I've had on hand; every audiophile needs that kind of a fix from time to time.

After awhile, though, the RS-1's peculiar (apparent) sluggishness gets to me, and I start to long once more for the delicacy and transparency of the Monoliths. Which just goes to show once again that, no matter how good a loudspeaker system is, there's always another one that does some things better. I am not just waffling when I say that I would hate to have to choose one or the other of these to live with exclusively. Although that doesn't help you make a choice, does it?—J. Gordon Holt

---

Footnote 3: Note that the "version" of the Watkins that I so much like with the Eagle is the original one. Current versions of the speaker may or may not be so ideal for use with that amplifier.