Issue 210 / February 2011
HP'S WORKSHOP
The Nola Micro Grand Reference Speaker
At the Heart of a State-of-the-Art System
Harry Pearson
It isn't often that a component comes along that genuinely electrifies
a seasoned reviewer, but thanks to Nola's new Micro Grand Reference,
now, for the first time in a long, long while, it has. And that
reviewer is me.
This speaker system is compact in size [9.5" x 24" x 9.5"] and contains only four quite small drivers: a single true-ribbon, one cone-type midrange, and two circular four-inch woofers. It is only marginally larger than many a so-called "monitor" speaker. But the first sonic impression it makes is of anything but small sound. It has a capacious soundstage, a kind of sonic purity, and the ability to unravel dense and complex orchestral textures. It can easily cull the sheep from the herd, losing neither sight nor context of either.
At first, I had decided to use these, the Micros, to take a listen to some tube-type gear I hadn't seriously auditioned, knowing full well that designer Carl Marchisotto of Nola speaker has long been enamored of ARC tubed gear (not to mention Alnico magnets in speaker drivers). And found, to perhaps my surprise, that the essential character of some of these electronics romantically Technicolored in a way I hadn't appreciated before. There were several units, an early Lars amp, and an older Hurricane unit from Antique Sound Labs that had more musical honesty than I'd suspected. And the Veloce battery- operated tubed linestage brought the Micros to life in a startling way, one that even took Marchisotto himself by surprise during our initial setup session. Why not, thought I, see just how far we can push the speakers in terms of sonic revelations? And so, over the next little while, out came the McIntosh basic monoblocks, the best-sounding McIntosh tube-based amp in years, new cables from Nordost, the less expensive, but still impressive Tyr units, as well as the new Neo-Classic table from VPI, along with a couple of standing reference units, the EMM Labs XD player and the Benz LP S-MR moving-coil cartridge.
The frequency response of the speakers, priced at $14,000 the pair, is said to extend from 38Hz up past 40kHz. (Their custom-designed stand is priced at $1200.) What we discovered was that the two Micros, set up in Room 2, had the capaciousness of a much, much larger system, and that from about 40Hz on up. Eyes closed, you'd never guess these were anything less than a big multi-speaker system, which is one of the most startling things about their performance. The one thing that was troubling, given the apparent flatness of the overall response, was a warmer-than-life sound from about 60Hz down to the speaker's lower limit and this we managed to eliminate by inserting an isolation transformer, made by Silver Circle Audio (the Pure Power One 5.0), into the system -- it is itself such a heavy-duty beast it could also handle the high-power of the Mac amps, not to mention everything else in the system. With the Silver Circle, the midbass became as pure and uncolored as the frequencies above it. This was a bit surprising to me. When I asked Marchisotto about it, he said that the alternating current from the outside power line did its worst damage at 60Hz and below and what I had been hearing was garbage, not the speaker. This sure made sense to me.
I began to wonder whether the larger Metro-References, just introduced (they are about the size of two Micros atop each other) could sound significantly better than the speaker I was so surprised by and just how much better the Baby Grands, the first system in Marchisotto's new line of breakthrough designs, themselves reviewed in a previous issue by Jonathan Valin (who was quite taken with them, as have been many of those in Audioland who've sampled their delectabilities). I hadn't and haven't heard either. More on these speculations in a moment, or so.
I said breakthrough in Marchisotto's design work. As many of you may know, Carl did his apprenticeship under Jon Dahlquist, and later branched out on his own, founding Alon, later to become Nola, which is Alon spelled backward. Up until the reference line, every Marchisotto design I've heard (and I've heard most of them) sounded suspiciously and remarkably like music, with nary a sonic misfire in the bunch, from the Thunderbolt woofers to the four-speaker assault on the state of the art, the Reference. I now think that part of his secret in the early design work lay in his skill at working around the non-linearities and colorations in the materials he had to work with. With the new reference systems, he has, based on what I am hearing with the Micros, eliminated, and to a substantial degree, the forgiving characteristics of his previous work, and left us, the listeners, with a higher truth, a far closer approximation of the music itself. The euphonic colorations have become so vanishingly low they seem to have disappeared, leaving in their place more of the music itself.
What we get in addition to the much lower coloration, or perhaps because of that, is increased resolution in those subtle cues of overtone structures, the subtle harmonics that let you tell one instrument from another, as well as an uncanny ability to differentiate dynamics, particularly the lowest pianissimos in the microdynamic scale. And such is achieved without the "etched" plastic-like credit-card sound of too many of the so-called high-resolution systems. With the Micros you can hear more of what's going on with and in your source material. As we shall see in Part II of this essay, the Micros are capable of defining the most elusive nuances of the best equipment preceding them in the chain, the more "alive" and uncolored is that sound.
Some thoughts on the speaker's innards and their cost. First, the cost: $14,000 the pair, eminently fair given the performance and the attention to detail evident in the construction of every pair. And, nota bene, you will want the stand ($1200) designed by Marchisotto's daughter, Kristen, which is open, elegant, and svelte in appearance, enhancing the performance of the Micros. Marchisotto calls the Micros "a three-and-a-half-way design, like that of the Baby Grand." To wit, as noted, there are two bass drivers -- tiny little things -- a cone midrange, and the best single-element true ribbons I've heard, the expensive and beautifully assembled Raven -- this unit specially designed to Marchisotto's specifications by the California-based company. "This new driver," Marchisotto writes, in a note to me, "now has twice the magnetic force from its neodymium magnet system, with twice the acceleration and better control of the ribbon itself." The crossover is set at 3.5kHz.
Of the two woofers, the lower one is rolled off around 200Hz, and the upper continues up to 400Hz, where it crosses to the midrange driver. Marchisotto lists the frequency response as extended from 38Hz to 46kHz. To enhance the bass, he has an open port in the rear of the speaker tuned to about 45Hz, and you may well hear a thickening of the sound in that region, unless you luck out and do what we were able to do, caused by incoming garbage from the AC lines centered about 60Hz. (See Part II.) More. Says Marchisotto: "All the crossover slopes are gradual, for good phase and transient response, between six and 12 dB and not a classical design... the twin bass drivers use cones of magnesium... the midrange uses a tri-laminate cone with a pulp base for low mass driven by a specially design Alnico magnet system, the Columnmax III." You want more still? "The magnesium cone drivers used in the Micro have a first resonant break-up mode at 10kHz, but they are used only to 400Hz, making them non-resonant true pistons over their entire operating range. Moreover, the advantage of magnesium is that when it does break up, it does so with a single frequency mode instead of multiple frequencies as with other rigid cones ...." One more thing: Marchisotto places ball-bearings in a platform under the speaker (and above its stand) to provide even further isolation from vibration-induced noise and colorations.
I detail these because I think each and every aspect of the system design contributes to the sound of the Micro. This is the work of an artisan, who has through experience (and he has one of the most critical ears in the business, and does not suffer fools) turned what has been his trade into an art.
I can't say that I can yet describe the speaker in a descriptive language. I am still working to get there. And this troubles me -I don't like saying you have to hear it to believe it. And that is why I am, at the point, only halfway (if that) into the assessment.
For my part, I think that the Raven tweeter and its careful matching to/with the other drivers in the system is the key to the speaker's impact and overall success. Perhaps I underestimate the tonal neutrality of the other drivers in the system. I do not yet have their full measure yet, but I do know the speakers are as good as I'm suggesting here. I'm just not able to say all the things that make them so very good that is, what these speakers can do, at least in the department of retrieval of the fine details usually, if not entirely, inaudible on lesser designs. What I do know and did from the start was: These are the best small speakers I've heard. They don't sound small. Nor hard, nor congested nor congealed on very loud passages when the Macs are chugging it out. And I, with increasing experience, have seen more in my reference CDs and LPs, which I feel as if I'm discovering all other, again.
What I get instead with my many reference recordings, both CDs and LPs, is this: There is, to put it more directly, less in the way, less between the music and me. And this would not have been the case if the speakers weren't what they are. I call this quality "translucence," not in the usual sense of that word, but in the sense of the original Latin, that of letting the light come through, the music is the light (and a gift to all of us). The point of high-end audio, as far as I'm concerned, ought to be removing a sense of the equipment from the reproducing chain, and allow us to get through to the truth of the absolute, that is, music. The equipment is an avenue to the music, and should not, as it is all too often these days, treated as an end in itself.
How did the Micro Grand Reference come about?
About a year and a half ago, I was thinking that I could use a reference monitor loudspeaker that was small and yet had the sonic presentation of our larger models, such as the Baby Grand. I wanted to use it to evaluate component parts, without having to deal with our heavier larger models. Also the monitor speaker had to have resolution similar to the Baby Grands, especially in regard to spatiality.
It seems most companies when asked to produce a small monitor, even one of high quality, seem to revert to a two-way, two-driver design in a box. As good as this type of design can be, I knew it would not have the spatial presentation and resolution of the Baby Grand.
What if, I thought, instead of the two-way "monitor" design, this could be a scaled-down version of the Baby Grand? Could that be done: a 3-way, 4-driver, three crossover-board design, which would be in fact a miniature Baby Grand!
I decided to employ twin 4-inch woofers that have the same magnesium cone technology and very-low-distortion linear motor systems as those of their bigger brothers in the Baby Grands. These turned out to require the very same large magnets that are used in the two 9-inch Baby Grand woofers. I thought an 86dB efficiency rating would be OK for a small speaker with a 38Hz reach in the bass. A 38Hz bandwidth would allow much of the spatial information to be reproduced. Since I knew that twin 4-inch woofers would not be able to move enough air to provide useful low-frequency output, I decided to employ a ported system using a very large double-flared port, which was rear-firing in order to increase air-moving capability.
I still had no idea if this speaker would work. Instead of a line source of four ribbons -- we would use one ribbon. I thought that even this sole ribbon, because of its length, would operate more like a line source than a point source.
You use the Raven ribbon?
The new Raven, built for us. It has twice the magnetic force for double the acceleration and a faster settling time. Also distortion is even lower, with a raw driver sensitivity of 100dB.
It seems other speaker manufacturers do not want to invest in a true Raven: we had to pay for a whole production run that was exclusively for us. It is the most expensive true ribbon, but worth it.
You have always believed in the sonic advantage of Alnico magnets, even to the point of preaching about their superiority.
Yes, but the company manufacturing our proprietary Alnico magnet midrange driver was sold and we were forced to switch to another manufacturer. The previous manufacturer had assembled this driver by machine. The new supplier by hand, but he charged twice as much. Much to my surprise, the new hand-made drivers sounded significantly better and had faster transient response, and better resolution and transparency. I inquired if they were manufactured to my specs and the answer was yes. The engineers at the new supplier had no idea why they should be any different. They probably thought I was nuts.
How did you design the cabinet?
It is mostly a scaled-down version of the Baby Grand. The finish is the same true piano rosewood as in the Baby Grand. In my attempt to pull out all the stops, I designed the same type of ball-bearing isolation system for the Micros employed in the Baby Grands. This system was better at absorbing floor-borne vibrations than any other type we tried. The micro-movement of the balls riding in hardened-steel low-friction races was not a cheap fix, but it was effective. It works similarly to a suspension system on a turntable -- except there is no resonant frequency.
One major difference was this monitor would need a stand. We commissioned a heavy steel stand with a weight of 73 pounds to support the Micros. It worked well but did not match the piano finish of the speakers and as anyone who knows me knows -- I hate mass. My daughter Kristen had an idea for a stand and its look would be apt. Her idea was a specific shape with as much air around it as possible, and this was in keeping with my wish for low mass, as well. We found that Kristen's stand outperformed the conventional stand throughout the crucial midrange where most stands produce coloration. Kristen's stand weighs just 12 pounds and allowed more transparency than we had expected. We could now "see all the way to the back wall" with a stand-mounted speaker! Strange.
How would you assess the results?
We took that first pair down to Lyric Hi-Fi to see what they thought. Of course they scoffed. I insisted that they try them in the back room with the best gear, and I set them up in front of the Grand Reference Main Towers. I did not think they would fill the room -- but they did.
When other people listened -- they were fooled into thinking the Grand References were playing!
We repeated this demo in front of the Baby Grands at our Dallas dealer with the same result. We played the speakers for members of the Dallas Symphony, and they said it was the closest they had ever heard to the live sound of the orchestra! Wild.