PMC prophecy9 speakers
The PMC prophecy9 is an impressive feat of design and engineering. Quite apart from its acoustic qualities the way that the vent for the transmission line has been incorporated in the prophecy speaker range has reduced the cost of construction in numerous ways. The top dog prophecy9 replaces the twenty5.26i model in the outgoing range, both speakers are of a similar size but the new model has an extra bass driver and costs a thousand pounds less. PMC have achieved this with more efficient cabinet manufacture, the twenty5i models had a parallelogram profile which can’t have helped, economies of scale through the use of the same woofer throughout the range, and more economical packaging. They also avoid costly finishes like piano black in the prophecy models.
That they have been able to do this whilst offering refined technology and, as you will read, significantly increased sound quality is quite an achievement. The drivers in the prophecy9 are more numerous than a 26i too, albeit two five inch bass drivers replace a single six and a half inch example. This allows the cabinet to be slimmer which is a fashion that PMC have long backed, presumably due to aesthetic as well as acoustic demand.
The prophecy range does look a lot better than its predecessor too, I like the oval face plate that in the prophecy9 houses the mid and treble drivers with its Nextel finish and nicely styled wave guides. I also like the lump of aluminium that forms the base and Laminair X plinth with its curved interface to the cabinet, it’s an elegant speaker whose 165mm width means that it takes very little visual space in the room. The absence of outrigger feet helps to maintain this minimal profile and apparently the weight of the plinth means that the speaker passes tilt tests.
Laminair X is more than a cool plinth, it forms the end of the transmission line that starts behind the bass drivers and provides the lowest bass frequencies in phase with the output of the direct output of those drivers. It takes the fins introduced in the plastic vent terminal of the twenty5 series and extends them to the back of the cabinet where energy from the rearward output of the drivers is turned into a laminar flow in order to minimise turbulence when it hits the relatively low pressure of air in the room. By using an aluminium extrusion at this point PMC have reduced colouration in the bass and made it far cleaner.
The waveguides around the mid and treble drivers are not just used to make the prophecy9 look cool, like much of this speaker they are derived from work that PMC has done in its professional speakers to enhance low frequency capability and control dispersion. Both the domes are derived from pro models, the 27mm tweeter and the 55mm midrange are both soft domes that are capable of delivering high power with low colouration as required in studio environments. We may not listen in studios, thankfully, but many of us play our music at levels approaching those found in those environments, so it’s gratifying to know that you aren’t going to fry your drivers when doing so even for long periods.
The waveguide on the prophecy9 tweeter is described as a shallow oblate spheroid profile, it looks like a shallow horn but what do I know, its function is to increase low frequency sensitivity (like a horn) and control and smooth off-axis dispersion (unlike a horn). Both factors help it to integrate with the midrange dome, ensuring that both drivers have very similar dispersion characteristics. Merely crossing drivers over so that there is minimal gap in frequency terms is not enough to ensure that they blend seamlessly in the room, this is because the shape of the acoustic wave they produce becomes narrower as frequency rises.
The midrange dome has a more complex waveguide dubbed n-compasss that combines two profiles, a shallow exponential guide and a steep hyperbolic one. The latter provides increased low frequency sensitivity while the hyperbolic adds the off-axis dispersion control that is the key to driver integration. There is a third benefit too, when combined these profiles diffract high frequency information, that is the sound bounces off the shapes to radiate in a wider array. It’s all clever stuff but would not be worth considering if the results did not back up the theory, fortunately they do.
The prophecy9’s twin bass drivers are dubbed LT XL, this stands for the extra-long throw provided by an extended voice coil and a matching motor assembly, the idea being that the coil remains in the magnetic field even when at maximum excursion. In sonic terms it means deeper and more powerful bass, and of course two five inch cones have greater driving area than the twenty5.26i’s six and a half inch driver. The cones themselves are mica filled polypropylene types with ultra-low mass for maximum control.
Sound quality
I used my trusty Moor Amps Angel 6 power amplifier to drive the prophecy9s, its 150Wpc proving well up to the task. PMCs are generally low in sensitivity but present a fairly benign load, this one has a 4 Ohm nominal impedance and quotes sensitivity at a high 91.5dB so slightly bucks the company trend. What they need is decent quality rather than large quantities of power and that’s what I gave them. They responded with prodigious low bass and exceptional depth of image when playing Nils Petter Molvaer’s Quiet Corners. Bass that is totally devoid of overhang or thickening too, conventionally ported speakers frequently impress with quantity of bass for box size but it usually becomes clear that they have been tuned that way and that the bass cannot match the midrange for speed and clarity. In the prophecy9 you get both to a degree that is very rare.
Thanks to Steve Pearce from B&W I recently discovered a particularly fine Bob Marley track called No More Trouble (Jamaican Extended Instrumental), which combines superb musicianship with great sound. Here the piece was really well separated, the bass line, guitars, drums etc all being easy to follow individually but coalescing to create a fabulous groove. You can hear the vintage of the recording well enough but its recent remastering proves that Chris Blackwell knew what he was doing in the studio back in the day. The more music I played the more it became apparent that the prophecy9 has a transparency to detail that is in another league to much of its competition. Everything played offered up the nature of its composition, tonality and performance as well as the character of the recording with a degree of clarity that laid everything bare yet retained coherence and musical brilliance.
Sometimes you hear stuff that would perhaps be better left in the blurring that many speakers suffer from, tape hiss on Yussef Kamaal’s Remembrance for instance, but this is soon forgotten when the rim shot and the shimmer of its decay nails the tempo, leaving acres of space for the keys to wander where they will. You have a choice with this speaker, listen into the recording to hear what each player or singer is contributing and how that contribution is mixed, or enjoy the combination of their efforts, the whole that is greater than the sum of its parts. I heard an interesting BBC documentary (50 Years of the Koln Concert) about the recording that put Keith Jarrett and ECM on the musical map. It inspired me to play it on the streamer where the ‘broken’ and tonally thin nature of the piano is still evident but that takes second string to the extraordinary nature of the improvisation, the PMCs revealing precisely why this performance became so popular by emphasising the musical message over the tonal challenge.
Reviewing Jarrett’s latest release, New Vienna, it’s easy to hear how, while he is on a different plane 40 years later, he still has the same intensity and soul baring ability even though some of his playing is less easy on the ear. In many ways the prophecy9’s ability to get to the heart of the music by being so faithful to the recording, is more impressive because it doesn’t let the aesthetic side of the equation get in the way of the communication.
With the gritty tones of Arab Strap’s Packs of Three you hear how the drums have been treated and the keyboards really shine but it’s the speed of the snare and the round juicy character of the bass guitar that takes the biscuit. The lyrics are excellent but it’s the musicianship that makes this piece so vivid and engaging. I was also surprised by how clean the usually thick sounding New Moon at Deer Hollow sounded, Mick Karn’s Rain Tree Crow sound so articulate and tonally precise that when the bass notes from the synth come along you are caught off guard by their depth and precision.
Conclusion
This is an uncannily neutral and low colouration loudspeaker, one that does not attempt to make the music it produces sound warm, fast, sweet or powerful but aims to render it exactly as it sounded in the studio or concert hall. Having feet in both pro and domestic audio camps allows PMC to understand what it takes to deliver this degree of fidelity, the prophecy9 is the summation of that knowledge in a slim elegant and domestically appealing form. It is, in no uncertain terms, an absolute cracker.