Acoustic Research MGC-1 loudspeaker Page 2

Anthony H. Cordesman wrote about the MGC-1 in October 1985 (Vol.8 No.6):

There are only four roles a reviewer can perform. One is that of guide: helping the reader find products that merit his attention, calling his or her attention to key merits and problems, and providing tips on how best to enjoy the product. The second is that of dictator: telling the reader to march down and buy what the reviewer says. The third is becoming the product or performance: making the reviewer, and the review, more important than the component under review. The fourth is whore: promote products, advertising, circulation, particular test procedures, accessories and modifications, etc.

Unfortunately, no reviewer sticks perfectly to the only one of these four roles that has integrity—the first. Being a guide, however, is a role that has special importance in dealing with the Acoustic Research MGC-1 speaker. This speaker merits serious listening. Even if you don't fall in love with it, at least one prolonged listening session is essential to your future understanding of the role of ambience and reverberant energy in any sound system.

If you don't accept these words at face value, try a simple two-minute listening test at your local AR dealer (but check first—they don't all sell the MGC-1). Bring a record or CD with lots of soundstage data. Listen to the MGC-1 speaker with the ambience energy on; then, simply turn off the ambience speakers, and listen to the soundstage and musical life die.

Remember: the direct speaker will still be providing the normal output of a high-quality acoustic suspension speaker, albeit one with greatly restricted dispersion. Judge for yourself what the MGC-1 tells you about most box speakers, and why so many reviewers go for large apparent sound images and bipolar speakers.

In spite of its complexity, and an Acoustic Research reputation that has tarnished over the years, the MGC-1 is a serious audiophile product designed for audiophiles by an audiophile (Kenneth L. Kantor of AR). It provides overall sound quality of definitely high end caliber; it indicates that AR may be striving to regain the identity and concern for sound quality belied over the last half a decade by its post-AR-2 and -AR-3 loudspeakers.

The fact that the MGC-1 is an important speaker does not, however, mean that it is perfect. On the plus side, it provides the most musically convincing illusion of the ambience of a live performance of any speaker to date. It succeeds in creating this illusion over a wide area, in a wide range of rooms, and in a musically coherent form. It does not create artificial ambience; it simply provides the listener with the ability to extract what is actually on the record or CD. This is an important and unique achievement.

The MGC-1 achieves these merits, however, at the cost of three important trade-offs. First, its bass does not extend much below 40Hz—a significant flaw in a $3600/pair speaker system. Second, the speaker is not as dynamic as much of the competition in its price range. It does not handle major shifts in musical power and volume with the speed and life that is desirable. Finally, it has a touch of what Gordon Holt calls the "Boston sound": the upper octaves seem slightly rolled-off, lacking the life and air of electrostatics, ribbons, and EMIT/EMIMs.

The Case for Extended Listening Under Controlled Conditions
This mix of merits and trade-offs makes careful prepurchase listening even more important than usual. This listening should use familiar source material, and involve at least a couple of hours of trying out the many adjustments in reverberant energy that the Delay Ambience Control box makes possible. There is a natural progression from excitement (exaggerated ambience) to irritation (incorrect settings) to finding out just how good the soundstage and musical coherence can get.

The Ambience Level control is particularly tricky—the natural tendency is to add too much, then blame the speaker. Patience reveals, however, that a properly adjusted MGC-1 can create a realistic soundstage with virtually any music. Further, extended listening shows that the proper setting will provide far more apparent treble detail than you get from just a casual set-up. Too little ambience data makes the music go flat; too much smears the harmonics and transients.

The Soundstage, Wall Distance, and Ambience Balance controls are also important, and prolonged experimentation is mandatory; these controls offer an incredible degree of flexibility in tailoring the ambience to suit a given recording. The chances a given dealer's taste will coincide with yours is negligible. A good dealer will allow you to do this with the AR stereo remote control unit (practically mandatory with the ambience unit—no high-end audiophile can ever leave well enough alone).

You should pay close attention to the dealer's set-up and some of the MGC-1's placement requirements before embarking on any serious listening. This is not a speaker to mix in with a lot of other speakers; any dealer who does so has a largely worthless demonstration. The MGC-1s are not particularly placement- sensitive, providing the illusion of a stable point source over a fairly wide area, but their set-up does require some care—either at the dealer's or at home. Ideally, each of the speaker units should be placed about one-quarter of the room width from the side walls and a reasonable distance from the rear wall. In spite of their weight, which should obviate the necessity for such devices, the MGC-1s benefit strikingly from the use of spiked feet.

The MGC-1s also provide a far more convincing illusion if the listening area is slightly closer to the speakers than usual, and any interference from heavy items of furniture between speaker and listening area should be avoided. Vertical dispersion is also limited (by design); listening must be done while seated.

The Case for Reading the Manufacturer's Literature
Though it isn't essential, I encourage you to read up on the speaker's technology in a paper the designers—Kantor and Alexander P. de Koster—gave at the 77th AES convention. I also found it helpful to take 10 minutes and actually read the instruction manual before sitting down to play.

The MGC-1 does not rely on clever or cute effects. It obtains the advantages of both narrow and wide dispersion by sending a main "first arrival" signal that is exceptionally free of reflected energy (hence the rectangular cone- shaped foam forming a kind of horn for the drivers), and following this with a slightly delayed reflected signal. The net effect is to "expand" the listening room by the equivalent of nearly 20 feet in each direction, simulating an environment in which both full orchestral music and solo voice sound natural.

Equally important, great technical effort has gone into reducing any interference in the imaging data received by the ear. This should show up clearly during listening: there is no excitement to the imaging; it is not thrown forward or backward; it does not suddenly move; it produces no new friendship clusters of instruments. If patient in making your adjustments, you will hear imaging that is state-of-the-art.

More About the Trade-offs
I have already described the fact that the MGC-1 has some important limitations—deep bass, dynamic energy, and life in the upper octaves. I've stressed careful auditioning because, after all, you're paying for the MGC-1's strength, or "illusion," at the expense of these other problems—you should at least get the strengths right! Go a bit further: compare the MGC-1s with the Infinity RS-2bs, Quad ESL-63s, Magneplanar MG-IIs, Thiel CS-2s (though the CS- 3s are closer in price), and Vandersteen 4s. This will give you a good idea of the trade-offs available, and necessary, in this price range.

You should also be aware that (a) Acoustic Research plans to make a more "affordable" version of this speaker technology available in the near future, (b) Polk SDA speakers and Carver electronics provide some of the same sonic benefits at a lower price (though using very different technologies and in a far less convincing and musically natural form), (c) leading manufacturers like Infinity are working on their own approach to ambience, and (d) some of the MGC-1's benefits offers in terms of imaging are possible with ordinary speakers through the use of the Monster Cable Acoustic Imager.$s1

Summing Up
The MGC-1 is an important product: any audiophile owes it to him or herself to hear it. I could spend much more time on any aspect of the MGC-1's design and performance, but the whole point would still be to get you to listen for yourself. In fact, let me close by reprinting the designer's recommended list of demonstration records and compact discs. You may already have many of these records and CDs; they comprise a good list of source material for auditioning this speaker. More important, they are a solid indications that the MGC-1's technology responds to music, rather than attempting to dominate it.—Anthony H. Cordesman

Footnote 1: See the brief write-up of the Acoustic Imager in "Hot News," Vol.7 No.8.—Ed.
Acoustic Research division of Audiovox/VOXX International

contest's picture

I still have my AR 3a speakers from 1975. Still sound great.

corrective_unconscious's picture

Shades of the Concert Grand SI from ESP Loudspeakers? Even though those were more meant to derive from the Beveridge line source, rather than being a very low dispersion radiator with delayed ambience drivers, there are some similarities in terms of general form factor and how various drivers aim off from the central axis, imo.

I like some of the theoretical ideas at work here, and wonder what could be done with a modern implementation.

Dingus Mcgee's picture

i have Ken's old pair of MGC-1's that i was able to restore with the help of a friend. i couldnt procure a working MGC-1e ambient controller, so i use an HT receiver to drive both driver arrays, using the front arrays as main speakers and the side firing array as surround speakers.

i also installed a center speaker and dedicated sub to outfit the system. this works quite well, but i do not employ a delay to the side arrays and instead rely on the receivers dsp abilities to reproduce stereo recordings in a 5.1 mode. surround recordings are reproduced in true 5.1 with glorious results.

i have yet to hear the MGC-1 as they were designed to be used, but my modern version of implementation is jaw-droppingly good.