[Jesse]

This is my review from about 2 years ago. I read it again yesterday. I feel even stronger about my findings now. I've tried many different XO points, slopes and Q settings but after 2 years of adjustments, I have to say that Magnepan got it right the first time. Their stock settings can not be improved on in my opinion. For anyone considering bia-mping Mags, this may help.
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By setting the XO frequencies and slopes close to the Magnepan 20.1 stock settings (high pass @ 250Hz 6dB and low pass106Hz 18dB, Q settings medium) the initial result was astounding.
Once installed the increase in detail was immediately noticeable. The clarity is pristine. But by far the most jaw dropping increase in performance is the bass. The bass is accurate and it is real. The bass pounds through the room without the slightest hint of overhang or colorations. The bass instruments sound so real I simply fall short of the words to convey the image set before me.

These changes are not subtle. You don’t have to sit and listen closely with a friend and strain to hear supposed improvements. You don’t have to A/B anything. You don’t have to read reviews to help you decide if you’ve done the right thing or not. Incorporating the XVR1 is almost like listening to an entirely different system. It takes every good trait of the system and hands it to you on a silver platter, then it looks at you with those two bright blue eyes it has and says - “you’re welcome”.

The highs are fully extended with more detail and even less digital edge than ever before. The McIntosh MDA1000 is the only other piece of gear I’ve ever had that gave me an instant noticeable performance gain in this way, more detail less harshness. That in itself is a great feat of technological achievement in my book that very few companies can manage to do. But the XVR1 "allowed" the gear to take it way over the top. The highs have become so clear and detailed with zero listener fatigue that it is simply astonishing. It is very pleasing to hear so much more without the usual trade off of unrealistic magnified detail and harshness. There is simply no limitation to the extension in the highs. Airy out to infinity. You forget you are listening to wires, circuits and mylar. If forces you to listen to the music because, you just can’t help it.

The mids and highs come together to offer a tonality that approaches a daunting realism. It’s a bit ghostlike in the stage. With quality recordings it’s as if you can begin to see around the sides of the singers head forming somewhat of a holographic presentation to the minds eye. The bass is beyond anything I’ve ever heard. It is so powerful and accurate it belies the mind to imagine this kind of bass pressure without bass modules or subwoofers of some sort. It is phenomenal. If anything is going to drop your jaw, it is the bass performance gained by incorporating an electronic XO in a well arranged system. Full range dynamics is off the chart.

Furthermore, the bass instruments are palpable. You don’t just feel them. You see them. Bass note origins are visible and placed on the stage with incredible accuracy. All of this together has brought about imaging taking on somewhat of a 3D effect. You begin to see the actual strings of a stand up bass as the musicians fingers pluck and move up and down the neck. The realism is impossible to describe. It must be heard.

I've heard it said, "Maggies don't do bass." If you believe that, come over here and prepare to be humbled.
I never thought there would be this much magic chained up inside the Macintosh / Maggie 20.1 system. Active biamping has proved to be like the key that unlocked all the potential of these world class components. It’s like the amps are saying “thank you for cutting loose that 200 pound lead weight, now we’re going to show you what we can do”. The Magnepan 20.1 has accepted the challenge and proved worthy as if to say “it’s about time you gave us what we need”. They are just eating up all this efficiency with sophisticated style, ease and boat loads of control.

While the mid/hi amp meters seem somewhat normal in there tracking of the power, the bass amp meters are bouncing to extremes from 5.0m to well over 50+ watts like a pogo stick. The bass amps are free to let it rip, and boy do they ever. The way those meters are bouncing around, the amps just look happy and free from any restraint.
Just for kicks I installed the stock crossovers back on the speaker to see what difference it would make. With the XVR1 and the stock crossovers working together, there were all the improvements I mentioned above but to a much lesser degree and would be a judgment call of whether it would be worth the investment or not. That little experiment showed me that the passive XO was the most inefficient piece of gear in my entire system.

The passive XO is like a wall of resistance. Certainly a necessary component but if you never plan to electronically crossover your speakers, do yourself a favor, don’t ever listen to someone who has. If you do, you will either spend the money necessary to get active or you will always know in the back of your mind what you’re missing.
The XVR1 removes obstacles. It didn't change the basic qualities that originally drew me to purchase my particular gear. What it does do is allow what you have to fully shine in whatever glory it was designed to have. You can just imagine the shine that an MCD/MDA1000, four 501’s and a pair of Magnepan 20.1’s has.
Coherence is a good word that fits the results of the stage and imaging performance. The stage takes on a "whole" coherency defining space and time of a live performance You are with the performers. The dynamics as a whole reach new levels.

Isolating the frequency spectrums allows the amps to play quite loud and remain cooler than before. I tell ya, it's an amazing set of benefits this active biamping provides.
Hearing the full potential of an all Mac front end supporting the spectacular ability of the 20.1 has got me ready to go to my CD collection and start with AC/DC (only Bon Scott of course) and listen to every single CD I’ve got right through to ZZ Top. The way I see it, I’ve got a lot of new music to hear.

I hear some express concern with diffusion. Below is an excerpt of comments that I agree with from Warren at avguide.com on 3/25/09
“Set up properly, MG 20.1s do not suffer from diffuseness. Getting precise symmetry and the toe-in angle exactly right is critical. Use a naturally mic'd vocal and adjust for correctly tight focus of the mouth size. Get it wrong and you have "clown mouth" syndrome; get it right -this includes having sufficient distance from the rear and side walls and their judicious damping- and the scale of the origin points of each voice and instrument will be properly life-size, but not over-blown.
Maggies, the messengers, are often blamed for other problems they tend to magnify. Getting Maggies to sound their very best can require biblical patience in partnering and positioning. When you get there, they will have challenged nearly all of your assumptions based on other speakers.”

MCD1000
MDA1000
Pass Labs XVR1
501 (4)
Magnepan 20.1
Equtech 3Q
Long live two channel.