PMC PB1i Floorstanding Loudspeaker (Hi-Fi+)

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PMC PB1i
PMC PB1i Floorstanding Loudspeaker (Hi-Fi+)

[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.

The one thing that PMC was quick to demonstrate with the PB1i is its ability to play at high levels, those two bass drivers provide an ease and consistency at any volume but which comes into its own then the wick is up. That said these speakers remain much the same at moderate levels, revealing the depth, width and scale of everything you play. They therefore excel at stereo imaging which can be extraordinarily physical with the right recording. I played the Avishai Cohen Trio quite a bit and there was no getting away from the solidity of the band leader’s double bass, its big wooden body standing between and in front of the speakers in visceral fashion. On another track, the drums are placed well behind the rest of the band in an unusually tangible fashion. I thought that this might be down to the MSB source, but got the same result from a Moon CD3.3 player, too.

If this speaker has a character, it is a relatively relaxed bottom end. Because the bass really breathes you don’t get the same solidity or tightness that you get with a well built ported box. But put on the right track, one with a solid kick drum and that tight, powerful drum sound comes through. All of which makes me suspect that the ATL approach could well be the less distorted. The fact that there is so much range of bass character available from the PB1i suggests that it is not making much of that character up itself, rather it is revealing it in a truthful fashion. With the Moon player, however, the overall result was a little soft and I got much better results with the other two sources at hand, so you still need to match front and back ends to get the right final balance.

My B&W 802Ds produce tighter bass, great definition of leading edges and more character seems to come through the midband. However, its presentation is completely different and while power handling is slightly greater and overall resolution higher the amount of extra detail that one can confidently say is coming from the recording and not the speaker is not so great given the three grand price differential.

The PB1is do like a bit of power behind them. I tried using a Leema Tucana integrated, which is a pretty powerful unit. While it produced an engaging and revealing result, it was not terribly comfortable at higher levels in what is admittedly quite a large room. One interesting point was that the speaker didn’t need that much space behind it to give an even response, I kept them a metre clear of sidewalls, but only needed half that behind them. Obviously different rooms will work in different ways, but with a speaker that goes down as low as this and with as much power, this was closer to the wall than experience suggests would work.

One’s attention is drawn to the bass because it reveals so much instrumental timbre, shape and depth in everything that goes down there, but the mid and top are easily on a par. It wouldn’t reveal as much about the qualities of recordings without a stunning midband and it wouldn’t reveal the shape of recording venues without good treble extension. Of course, all three elements are bonded together seamlessly by the fourth-order crossover.

Speakers with this type of crossover can have great detail resolution, but a poor sense of timing. While there are snappier sounding speakers out there, the PB1i is right on the money when it comes to this critical factor. Not only does the bass breathe but it is also fast, that’s why you can hear so much detail and why it can stop on the proverbial dime.

This is a hugely entertaining and revealing speaker and one that I was genuinely saddened to see leave the listening room. In tandem with a decent source and a powerful amplifier, it can create the illusion of musicians in the room with remarkable ease. And even with a compressed slab of Frank Zappa, it transports you to that other world where all that matters is the sound.

Technical Specifications

PMC PB1i floorstanding loudspeaker

Type: Three-way, four drive unit floorstanding loudspeaker
Sensitivity: 87dB/1w/1m
Impedance: 6 ohms
Frequency response: 24Hz-25kHz
Drive units: 27mm Sonolex soft dome treble, 75mm soft dome midrange, 2x170mm doped cone bass
Crossover freq.: 380Hz, 3.8kHz
Input connectors: 4mm sockets (3pr)
Dimensions (WxHxD): 204 1084 401mm
Weight: 26kg
Finishes: oak, walnut, black ash,cherry
Options: magnet shielding
Price: £5,500/pair

Manufacturer: PMC Ltd
Tel: +44 (0) 870 4441044
Net: www.pmc-speakers.com

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