I have just returned from an audio pilgrimage to Magnepan headquarters in White Bear Lake, Minnesota (a small community on the northeast side of the Minneapolis/St. Paul 'Twin Cities' area). What was the reason for my visit? Wendell Diller, Magnepan's head of Marketing and Product Development, invited me to a private listening session to audition Magnepan's latest prototype loudspeaker. This unnamed model aims to recreate in full the sound of Magnepan's massive flagship 30.7 speakers, but in a much more compact format suited for use in small-to-mid-size rooms. Diller has dubbed the prototype the '30.7 for Condos'.
Let's make this clear from the outset: the '30.7 for Condos' prototype is very much a speaker concept and not for sale. What underlines this proof-of-concept are some extremely innovative technological paradigm shifts, and this innovation will be the subject of at least one patent. However, viewed as a concept, the prototype is fascinating.
Understand that shrinking the size of the 30.7 while preserving its sonic characteristic is a very tall order. In a past Hi-Fi+ review, I described the 30.7 as one of the finest loudspeakers I have ever heard at any price—a comment I stand by even though I have never yet been able to listen to the 30.7 in a space large enough to tap its full potential. But, even in mid-sized rooms, the 30.7's excellence shines through.
To recap, Magnepan’s 30.7 is a large planar magnetic/ribbon type loudspeaker that consists of four large panels: two dipolar woofer/mid-bass panels (H x W x D: 200.7 x 73.7 x 5.2cm) plus two somewhat smaller midrange/tweeter panels (H x W x D: 200.7 x 36.8 x 5.2cm). The woofer/mid-bass panel houses three planar magnetic drivers (two side-by-side planar woofers, with a narrower planar mid-bass "coupler" along one side. The midrange/tweeter panels use a tall, slender quasi-ribbon-type planar magnetic midrange driver with a very slim and nearly six-foot-tall pure ribbon tweeter. The mirror-image pair of panel sets give a range of placement options; positioning the tweeter to the outside of the array yields huge soundstages, while positioning the tweeters to the inside of the array yields very sharp image focus.
Any way you look at things, though, the critical issue is the sheer size of the 30.7 system. The four panels of the 30.7 system stand just over 6.5 feet tall with a combined width of over 7.5 feet (and that's not even allowing for any spacing between the left and right sets of speaker panels). In short, the 30.7 system is so extensive that many listeners neither could nor would entertain having it in their homes, despite its incredible performance capabilities.
Enter the '30.7 for Condos'
What Wendell Diller et al., set out to do was build a speaker system that is fully the sonic equal of the 30.7, but is much, much smaller and that also retains the fast, deep, articulate, and resonance-free dipole bass for which Magnepan speakers are famous. All previous Magnepan speakers have used planar magnetic woofers that, as a matter of physical necessity, must be very large to have an adequate surface area. For the new '30.7 for Condos', however, a new approach for the bass portion of the system was required to reduce overall system size.
From the outset, though, Diller fiercely resisted the concept of using a traditional 'hybrid', self-powered, dynamic driver-equipped subwoofers (whether in sealed or ported enclosures). Diller reasons that such hybrid systems exhibit a noticeable lack of sonic unity between their monopole woofers and dipole lower-midrange/tweeter panels. While conceding that hybrid woofer-in-box bass systems may be satisfactory to a point, Diller believes they aren't suitable for speakers that seek to provide state-of-the-art sound.
To resolve this problem, Diller and team have come up with what they term a "Double Dipole" design, where a new dipole midrange/high-frequency panel handles most of the audio spectrum from the lower midrange on up. The new unit is based directly on the midrange/tweeter panel of the 30.7, but with all extraneous framework removed to achieve the smallest size possible. In turn, a set of radical, self-powered, and DSP-controlled dipolar dynamic-driver equipped woofer modules handles all frequencies from the lower midrange on down.
According to Diller, these new dynamic dipole woofer modules mimic the performance of the large 30.7 woofer panels. Like the planar panels, the dynamic dipoles can go very low and offer flat frequency response up to 10kHz—the same upper-frequency limit as the big 30.7 woofer panels. For this reason, Diller is considering trademarking the term 'Wideband Woofers' to describe the new modules.
While some manufacturers have experimented with dipolar dynamic-driver woofers in the past, none have been quite like the new Magnepan dynamic dipole woofer systems. Each Magnepan 'Double Dipole' woofer module features eight open-back 6.5-inch dynamic woofers. These woofers are purpose-built for dipole applications and fit on a V-shaped plate, with four woofers positioned on each side of the 'V' (the 'prow' of the 'V' faces forward towards the listening area). Regrettably, as this vital part of the design is subject to a patent application, it's the one part of the system that I was not allowed to photograph.
In prototype form, the woofer modules were each driven by Bryston monoblock amplifiers and controlled by external computer-linked DSP engines. If turned into a full production speaker, however, each woofer module would include a roughly 1kW amplifier with built-in, dealer programmable DSP engines. Importantly, the new 'Double Dipole' woofer systems are quite compact (86.4 x 35.6 cm, or 34 inches x 14 inches)—small enough to hide behind furniture, etc., to 'disappear' within the room. What is more, DSP controls mean that even if unorthodox woofer placement is required, the woofer's bass wavefronts can still be kept in time/phase alignment with the output of the main midrange/tweeter panels.
Completing the system is a set of midrange/tweeter panels that measure 182.3 x 30.5 x 5.2cm – noticeably smaller than the 30.7 tweeter/midrange panels. While discussing the design of the '30.7 for Condos', Diller commented that "the' 30.7 for Condos' is, like the full-size 30.7, a four-way design, but in the' 30.7 for Condos' we moved the mid-bass coupler function over to the midrange/tweeter panel." When I asked Diller to explain further, he politely declined to comment, merely asserting that Magnepan's overall "systems approach" to the design handles all mid-bass coupler functions in the new speaker.