During his recent tour of North American dealers, however, Diller discovered that even more adjustability was needed, especially in terms of matching mid-bass output to the requirements of various listening rooms. The most significant change that was incorporated from the first production units onward is a provision for adjusting mid-bass output levels as needed. To appreciate this change, it is important to understand that the 30.7 was designed from the outset to have sufficient low- and mid-bass output to be able to sound properly balanced even in very large rooms. This is all to the good for those who have truly large listening spaces, but it can lead to overblown bass in medium-sized or smaller rooms—a problem Diller wryly describes as being like “listening to a trombone in a phone booth.” Diller further observes that low bass is usually not the problem when moving the speakers from large to mid-size spaces, but that excess mid-bass very much can be a problem—a problem the newly adjustable mid-bass output levels help solve.
The main Austin Home Systems listening room, though certainly not a small space, is considerably more compact than the Magnepan factory listening room where I first heard the 30.7 several months ago. The space lent itself to an arrangement where Diller installed the 30.7 system along the longer wall of the room (marking the first time that I had heard the speaker in such an orientation). Driving the system was a PS Audio DirectStream Memory Player, and a DAC, preamp, and massive solid-state power amplifier from Bryston.
Accompanying me on my listening visit was Tom Martin, owner of Hi‑Fi+,The Absolute Sound, and Ultimate Headphone Guide. Since Tom’s time was limited we gave him first crack at the listening chair and very early on he commented on both the speed and uncommon smoothness of the 30.7’s midrange and high frequencies. I couldn’t agree more; in fact, if I could only point out one of the 30.7’s virtues, the one I’d choose would be the speaker’s midrange. It’s fast, highly transparent, and extremely resolving and yet somehow manages to sound effortless and natural at the same time (it never hammers the listener with the sort of enforced sense of detail that ultimately proves fatiguing over time).
We listened to the ‘Et misericordia’ movement of Kim André Arnesen’s Magnificat[2L, SACD] and marvelled at the achingly beautiful purity of both the voices of Lise Granden Berg (soprano) and of the Nidarosdomens jentekor (Nidaros Cathedral Girl’s Choir), which conveyed a profound sense of reverence as this haunting piece of sacred music was performed. But what also added to the experience was hearing the deep and powerful, but also very well controlled sound of the pipe organ accompanying the vocalists. It was in that moment, where the delicacy of the multi-layered female voices and the depth of the pipe organ notes merged—yet without treading upon or overpowering one another, that the true musical worth of the 30.7 as an accomplished full-range speaker became apparent.
Tracks with potent low- and mid-bass, such as the low percussion heard in the ‘Volcano’ movement of the Hovhaness Mount St. Helens Symphony [Schwarz, Royal Liverpool Philharmonic, Telarc, SAC] also showed how effective the 30.7’s new mid-bass control can be at taming excess mid-bass output in moderately sized rooms (though truth to tell I could have gone for even a smidgeon less mid-bass than the demo exhibited in Austin). But the key point is that the 30.7 now gives its owners the tools necessary to achieve a well-balanced sound in rooms of varying sizes and shapes. In fact, Diller estimates that the 30.7 could now be used in rooms as small as 14 feet ×17 like the demo he performed at the Madison, Wisconsin dealer’s store.