Product Review - Magnepan Magneplanar MG1.6/QR Full-Range Planar-Magnetic Speakers - September, 2001

John E. Johnson, Jr.

Over the past years, we have received many comments and questions about purchasing or using Magnepan speakers, or "Maggies" as they are affectionately known. Magnepan's speakers are in a category called Planar, meaning that, instead of a cone producing the sound, it is produced by a thin sheet moving the air. This category includes electrostatic speakers (ESLs) and planar-magnetic speakers. Maggies are planar-magnetic.

In the case of an ESL, a thin sheet (membrane) of plastic is suspended between electrode plates (stators). Several thousand volts of positive potential are applied to the membrane which is coated with a thin layer of carbon graphite to spread the voltage evenly. The audio signal from a power amplifier is passed through a transformer and increased to thousands of volts too. The signal is applied to the stators, one of which is in front of the membrane, and one of which is behind it. The alternating + and - of the audio applied to the stators repels and attracts the charged membrane forward and backward, moving the air to produce the sound we hear.

For planar-magnetic speakers, the technology is completely different, but produces a similar effect, i.e., moving a membrane forward and backward. Two sub-categories of planar magnetic speakers are ribbon and quasi-ribbon. Ribbon speakers use a thin metal foil suspended between permanent magnets. The audio signal flows through the metal foil and is repelled or attracted by the magnets, moving air to produce the sound. With quasi-ribbons, a thin plastic membrane substitutes for the metal foil, and a metal conductor is etched onto the membrane. The audio signal passes through the conductor, and the entire plastic membrane moves forward and backward between the permanent magnets.

Planar speakers are dipolar, meaning that when air is moved forward out of the front of the speaker, air is moving inward from the rear.

True ribbons are very light weight, but also very expensive. Quasi-ribbons are slightly heavier, but well within the average consumer's budget. Quasi-ribbons will have almost, but not quite, the high frequency response of the true ribbon. Magnepan MG1.6/QR are quasi-ribbons. At least that is what the tweeter is called. The bass radiating panel is more like a sheet than a ribbon, so ribbon is not the correct term, but you get the picture.

Design

The Magneplanar 1.6/QRs are one of Magnepan's most popular models, being one up from the smallest in the line. They have a 2" wide, 48" high quasi-ribbon as the tweeter, and a 442 square inch bass radiating panel. Crossover is at 600 Hz, with L/C crossover components in the base of the speaker. The lowest impedance is 4 Ohms, with higher impedances near the crossover frequency.

The rear panel has speaker binding posts for bi-wiring or bi-amping, but they are not conventional posts. You need an Allen wrench (supplied) to tighten a lock-down nut onto banana plugs or bare wire. Removing jumpers not only lets you bi-wire or bi-amp, but also to insert resistors (supplied) for attenuating the tweeter response. The tweeters have exceptional energy dispersion, and because they are dipolar, surrounding walls might be too reflective, particularly if you like hard rock music which tends to have treble rise. A 3 amp fuse protects the tweeters from too much current. The speakers sit on metal brackets, and the entire speaker is quite light for its size.

Placement

I need to say right away that the 1.6/QRs sound wonderful, and are relatively inexpensive, but there are a number of reasons why they are not in everyone's homes. One reason is that they are difficult to place in the room. I tested them both in our reference audio lab where I could put them six feet apart and sit 12 feet away dead center. Imaging and sound staging were excellent. But, in the real world, we don't always have an audio lab in which to listen to our hi-fi system.

Planar speakers need to be pretty big if they are full range. The 1.6s are more than 5 feet tall. So, where do you put them? In my living room, I tried several locations. The one that worked best was having one speaker next to the hi-fi cabinet and one across the room near near a doorway and in a corner (see photo at top of this review). That definitely is not an ideal arrangement, but if you must have a room specifically designed for audio, then what is the point? In this location, some of the imaging and sound staging were compromised, but the detail and transparency remained. Even with this, my wife and I preferred them to the floor-standing cone speakers that were there before.

I chose the off-white grille so that the speakers would blend with our light colored walls, and I moved a fern so that some of the leaves were in front of the panel. The radiating area is so large, this did not seem to affect the sound at all, but of course, you can always just turn the plant around for critical listening. This isn't supposed to be a lesson in interior design, but the speakers are not particularly spouse friendly, in my opinion, so you may need all the suggestions you can find in order to convince your significant other to let you have speakers in your living room that are almost the size of a door.

The two speakers are mirror images of one another, and the recommended positioning is with the tweeters on the outer edges (left tweeter on left outer edge, right tweeter on right outer edge).

Another reason you don't see these speakers everywhere is that they have low efficiency (86 dB/2.83V/1 Meter) and low impedance (4 Ohms nominal). They require a top notch amplifier to drive them. So, where you saved money on the cost of the speakers, you have to put money into a fine power amplifier. In this case, I used a Balanced Audio Technology VK-75SE balanced tube amplifier, along with a VK-5i preamp, Audio Alchemy transport, and Perpetual Technologies DAC. Cables were Nordost.

The Sound

Planar speakers are known for detail (because the transducer is light weight) and transparency (because the transducer is not in an enclosure). The 1.6s are no exception. Plus, since they are full range, even the bass is transparent. The entire room was alive with music. I could sit anywhere in the room and hear more detail than I could with the previous coned speakers. Imaging was not as focused, due to the fact that ribbons are line drivers, and the source is therefore spread out more than it is with a cone. However, for classical music, this is the effect that I prefer. For guitar solos, it sounded like there was a 12 foot guitar, so in this area (single instruments), the cone speakers win. However, regardless of how many instruments are playing, no cone driver can give this kind of transparency. It is as if you look through the speakers at the musicians.

For singing voices, I found that I preferred the Maggies at lower volume, again, in order to place the single voice in a credible space. For orchestral music, I cranked things up, but even the VK-75SE had its limits with such a demanding speaker, again pointing out the need for high power electronics (the 75SE delivers 75 watts per channel into 4 Ohms). Our VK-500 (250 watts per channel) and McIntosh MC-602 (600 watts per channel) worked much better. For operatic renditions, louder volumes were fine, because there were several people singing at the same time and they were spread out across the sound stage.

Since the amount of detail is so good with these speakers, I found that using a fully balanced amplifier (VK-75SE, VK-500, MC-602) worked best, because they have very, very low noise backgrounds. This gave me all the subtle nuance that the 1.6s were capable of delivering.

Even though I placed them in a non-ideal location, they nevertheless had a very natural tonality. No chestiness or boominess. No nasality or sibilance. Perhaps a little bass loading because of the corner, but in this case, it actually helped. I also added a small subwoofer to take care of the 20 Hz  - 40 Hz octave, placed near the left speaker, and because of its low frequencies, I could not localize it.

Conclusion

No wonder so many people corresponded with us about Maggies. They are terrific. If you can handle their size and placement limitations, and have a good power amplifier, you can't go wrong with these speakers.

- John E. Johnson, Jr. - 

© Copyright 2001 Secrets of Home Theater & High Fidelity
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