Meet Your Maker: Hi-Fi+ Visits Magnepan

Posted by: Chris Martens at 2:02 pm, April 24th, 2013

 

Here in the United States (my home country) the White Bear Lake, Minnesota-based loudspeaker manufacturer Magnepan enjoys a singular distinction; many members of the high-end audio press consider all three of the firm’s top models—comprising the 20.7, 3.7, and 1.7—as “best buys.” But here’s the interesting part: Magnepan’s speakers not only enjoy a reputation for providing terrific value for money, but for offering mind-bending levels of performance that place them either at or certainly very near the top of their respective price classes. So good are these speakers, in fact, that it is not at all uncommon (again, in the US) to find audio enthusiasts spending several time what the speakers cost in order to find electronics and source components able to do them justice. The only catch, relative to European norms in such matters, is that Magnepan loudspeakers are relatively low in sensitivity, offer low impedance loads, and therefore tend to work best with comparatively high-output amplifiers (think 100 Wpc and up). But, if you can cross that “watts-per-channel” hurdle, great sonic rewards await.

For those of you who have not yet had the pleasure of an introduction to the Magnepan range, let me sketch a few key points that will help you better understand the company’s products. All Magnepan speakers are relatively tall, thin, panel-like dipolar loudspeakers (meaning they radiate sound both fore and aft and have what many British readers might term a “figure of 8” dispersion pattern, as viewed from above). All Magnepan speakers use so-called planar magnetic panel-type drivers with top models supplemented by exotic and typically quite large ribbon tweeters (indeed, Magnepan holds core patents in the areas of both planar-magnetic and ribbon driver technology). 

Recently, I had a chance to visit Magnepan’s factory in White Bear Lake, partly to audition proof-of-concept prototypes for some new models the firm is considering adding to its range, partly to audition some uncommon configurations of existing models (for example, a pair of the firm’s flagship 20.7 floorstanders augmented with a pair of supplementary Magnepan bass panels, and partly to take a tour of the factory to see how “Maggies” (as we fondly call them in the States) are made. What follows is a photo blog documenting my tour of the Magnepan factory.

 

All Magnepans begin with construction of the outer frame of the finished speaker. Here a CNC router is carving the frame of a new Magnepan from a blank of MDF stock material.

After the machine-controlled routing step is complete, workers do careful touch-up and clean-up work by hand. As you will learn through this blog, Magnepan speakers—despite their relatively modest prices—require a terrific amount of highly skilled hand assembly work.

This image shows a stack of complete frames for Magnepan’s flagship model, the 20.7. For almost all Magnepan models, frames are made in matched mirror-image left-right pairs.

The next key step in assembly involves building the magnet-bearing perforated metal panels that serve at the core of Magnepan planar magnetic drivers. In this step, a perforated metal panel receives precision-placed linear bar magnets that run from one end of the panel to the other. Interesting, matched, stacked pairs of magnets are first placed on the panel, as shown here, with the assembly technician deliberately leaving a one-magnet-wide gap as you can see in this image. In a second step, the upper magnet in each set is then “unstacked” and installed in the gap provided. In this way, precise alignment of North-South magnet poles is maintained. The magnets are bonded to the perforated panels with an adhesive.

Here the technician lowers a set of completed magnet panels to a storage table to await further assembly steps.

The next essential step in assembly involves installing a metal perimeter frame on the magnet panels and then fitting the panels with the thin Mylar coverings that will serve as the speakers’ diaphragms (though the diaphragms do not yet have conductors installed at this stage). Here a technician prepares to install Mylar diaphragm materials to a pair of waiting panels. Magnepan uses a proprietary technique to tension the Mylar sheets in both X and Y axes before lowering the sheets onto the panel frames.

All content, design, and layout are Copyright © 1999 - 2011 NextScreen. All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.