Hi-Fi Plus: PMC PB1i Floorstanding Loudspeaker

Timeless Design

[This review originally appeared in issue 65 of Hi-Fi Plus magazine, which is published in the U.K.]

Design in East Germany during the GDR was as marooned as the lizards on the Galapagos islands, the packaging of products like scouring powder remained the same for over forty years. Likewise the Trabant car was never changed because there was no need to encourage demand when you had a twelve-year waiting list and there was no affordable or viable alternative. As a result what they did produce has a certain old world charm, the best examples have a simplicity that despite the crude execution gives them an aesthetic that is still appealing if unlikely to make much impact on your local supermarket shelves.

Although there’s few similarities between a loudspeaker factory and a former Eastern European country, PMC in its own way shares a consistency of design to its loudspeakers that stops them being attached to a particular era. Or at least that’s the way it seems, but look closer and you will see that the range has been refined in both aesthetic and sonic ways that has kept it looking contemporary without jarring with earlier models. The badge on the PB1i for instance is a lovely enamelled design that was introduced on the EB1i last year and gives the speakers a quality feel that is backed up by the real wood veneers the company uses.

The PB1i, so called because it is next in line to the OB1i, is a decent size floorstander with a pair of bass drivers, a dome midrange and the ‘i’ series tweeter. It is not a speaker that has been re-engineered to work with this drive unit but a completely new model that fills the gap between OB and FB. It is closer in style to the former by virtue of a similar baffle width, it’s only 4mm wider, and supports bass drive units of the same 170mm diameter. In fact it appears to be an OB1i with an extra bass driver. But it’s cabinet is 76mm deeper front to back and 59mm higher which accounts for the longer ATL or advanced transmission line. It also accounts for the extra quoted bass extension, which only amounts to four more Hertz but more is more, especially at this end of the scale.

The fact that the bass drivers are the same size is misleading because in most respects they are completely different, the power handling for instance is far greater than the OB1i LF unit as the voice coil is 38mm in diameter rather than 25mm. The magnet is three times the size. The cone, surround and spider are uprated and stiffer and are capable of far greater excursion. PMC’s MD and designer Pete Thomas did a lot of work on a the suspension and surround so that they provide linear braking for the cone. As a result, they have greater headroom and will take greater level before reaching maximum excursion.

This speaker has a newly developed ATL or advanced transmission line, which means that the size and length of the line has been tailored to the design as well as the way the line works. The line’s damping has to accommodate the twin driver arrangement, because the bass is produced over a greater length of the line than is the case with a single driver. This means the arrangement and density of the foams in this line are specific to the array. The damping is far more dense and fills a greater length of the line than that of the OB1i.

The PB1i also has heavy duty components on the 24dB per octave (fourth-order) crossover board. There are two massive air core inductors and these were selected to allow far greater current, something that the new bass drivers are designed to take. As the inductors are unlikely to become saturated this allows for greater headroom.

The PB1i is a rather special loudspeaker and I don’t mean that in the sense of it needing to take the special bus. What I mean is that it’s damn revealing and extremely capable. It doesn’t have quite the bone-mashing potential of the EB1i but it goes a lot further than most toward the combination of great resolution, power handling and domestic acceptability. I set the speakers up with glides rather than spikes because they don’t screw up the carpet and nor do they nail the speaker to the floorboards, which limits the potential for getting the floor to join in. Spikes are what PMC supplies however so that route is an option, even if it’s wrong! Ancillaries for the most part were Classé CP-700 preamp, CA-2200 power amp and either the MSB III series transport and DAC or my reference Resolution Audio Opus 21. And, while the speakers sounded cracking with the more affordable Resolution player, they revelled in the detail that the MSB pairing brings to the party.