Importantly, the 30.7 is Magnepan’s first-ever four-way speaker. The woofer/lower-midrange panel uses two differently sized rectangular ribbon-type planar bass drivers—an arrangement that means the two bass drivers have different diaphragm resonances thus yielding a smoother response curve overall. The smaller bass driver features—along its outward facing side—an also rectangular quasi-ribbon-type “transitional line-source driver” that covers lower midrange frequencies. Interestingly, the smaller bass driver and the lower-midrange line-source driver share a common diaphragm membrane, but use entirely separate voice coils, each optimised for its assigned frequency range. The drivers in the bass/lower-midrange panel use front and rear magnet arrays, just as do the drivers in the 20.7 loudspeaker—a design touch said to increase efficiency while minimising distortion.
The tweeter/midrange panel features Magnepan’s signature pure-ribbon linear tweeter widely regarded as one of the finest high frequency transducers in the world. The tweeter is positioned alongside a tall and relatively narrow ribbon-type planar midrange driver that introduces an all-new, proprietary, and ultra-low mass diaphragm material, which Diller says helps to make this by far the fastest and most responsive midrange driver Magnepan has ever produced. The midrange driver, like the other quasi-ribbon drivers in the speaker, uses front and rear magnet arrays. First order (6dB per octave) crossover networks are used throughout, with part of the network built into the bottom of the bass/lower-midrange panel and part built into the bottom of the midrange/tweeter panel.
By dividing its workload between four groups of drivers—a set of two planar woofers, a transitional line source lower-midrange driver, an extremely low-mass midrange driver, and a pure ribbon tweeter—the 30.7 aims, says Diller, to provide “lower mass (vs. frequency), better power response, and better bass” than any previous Magnepan design. It is also the most adjustable Magnepan ever, in that it allows separate adjustment of lower-midrange, midrange, and tweeter driver output levels and also positioning adjustments between the bass/lower-midrange panel and the midrange/tweeter panel. The good news is that the 30.7 can be made to work well in a surprisingly large variety of rooms (and to fit a broad range of listener tastes), but please note that it may take a significant time, patience, and experimentation to achieve optimal sonic results. For this reason, Magnepan requires all dealers wishing to sell the 30.7 to commit to providing the painstaking set-up and adjustment services the speaker needs and deserves.
What I hope to provide here is not so much a definitive loudspeaker review of the 30.7, but rather a preliminary assessment of its performance potential. With this goal in mind, I accepted an invitation from Magnepan to audition the speaker in the firm’s Minnesota-based sound room/development lab. During my listening session we drove the 30.7’s with an Audio Research Corporation CD6 CD player/DAC, an ARC Reference 6 preamplifier, and a pair of ARC Reference 250 valve-powered monoblock amplifiers, with entry-level Kubala-Sosna cables used. For part of the session, however, we removed the Ref 250 monoblock amps and substituted the power amplifier section of a prototype, third-party solid-state stereo integrated amplifier, mostly to see how the speakers would respond to solid-state amplification.
Beforehand, Diller positioned the 30.7 panels for ideal (and empirically verified) time alignment. In practice this meant all the panels were toed in toward the listening position, with the bass/lower-midrange panels placed near the sidewalls of the room and with the tweeter/midrange panels placed inward from the bass/lower-midrange panels and roughly six inches behind them. During the session, Diller and I made several small (yet cumulatively significant) adjustments to the various driver output levels, which helped the speaker to achieve increasingly more neutral tonal balance throughout the room. A subsequent pink noise test revealed that our efforts were largely successful, though Diller and I felt that, given more time for fine adjustments and selective application of room treatments, we perhaps could have improved further still on the speakers’ already superb sound.