In the beginning

Colloquially known as PMC, The Professional Monitor Company Ltd. was founded in the United Kingdom in 1991 by Peter Thomas and Adrian Loader. Previously, Thomas was a BBC manager and engineer. Loader was an engineer with UK audio gear distributor and custom installer FWO Bauch.  

PMC soon became a pioneer in the development of transmission line speakers. This type of speaker absorbs unwanted frequencies that radiate from the rear of the speaker’s bass drivers, resulting in high sound pressure levels and deep bass extension. By passing the lowest frequencies through a tunnel or so-called folded line within the speaker's cabinet that emerges from a vent, it is said that the upper bass and midrange frequencies have extremely low distortion and the speaker can play at low volumes without loss of frequency response.  

PMC obtained its street cred on the heels of its very first loudspeaker, the BB5-A transmission line studio monitor. The BB5-A found use in, among other places, the BBC’s fabled Maida Vale Studio complex and was favored by artists such as Prince and Stevie Wonder.  

Fast forward about 35 years and today PMC continues to move the art of transmission line speaker technology forward. Further, it offers not only an expansive range of loudspeakers, but also subwoofers, power amplifiers, and accessories that target the home audio and professional studio markets. 

The prophecy9 

The subject of this review is the three-way, transmission line prophecy9 ($12,999 USD/pair) speaker. It replaces the now retired twenty5.26i speaker as the flagship of the company’s six-model Prophecy line. 

PMC states that the primary design objective for the prophecy line was to create speakers with compact cabinets that have wide bandwidth, large, impactful low frequency sound, and exceptional “depth of voice” (i.e., the extremely natural reproduction of vocals). PMC asserts that its engineers sought to achieve these goals through a ground-up design and the use of novel technologies. 

The prophecy9 is indeed rife with proprietary tech, not the least of which are PMC’s Advanced Transmission Line (ATL) and LaminairX technologies. Complex in design, ATL was developed by PMC based on numerous factors such as the speakers’ dimensions and the properties of the cabinets’ internal lining materials. It is the key technology on which all PMC speakers are based.    

On the end of the ATL lies the LaminairX aluminum vent, which is built into the front of the prophecy9’s heavy, extruded aluminum base. The vent is said by PMC to smooth the line’s airflow by directing it through multiple channels with a diameter that exceeds that of a single channel. This, according to the company, reduces turbulence and creates clean, loud bass with no “chuffing” noise. 

The prophecy9’s 1” soft dome, ferrofluid-cooled tweeter, 2” soft dome midrange driver, and two 5.5” mineral-filled, polypropylene LT XL (extra-long throw) cone bass drivers are each designed in-house. The tweeter and mid-range drivers are housed by a profiled, Nextel velvet coated baffle and set into waveguides that are also of PMC’s own design.  

The prophecy9’s crossovers, which are said to feature “military-grade” circuit boards, thick copper tracks, and gold electroplating, operate at 0.6kHz and 3.2kHz. Frequency response is claimed to be 35 Hz to 20kHz (-3dB). With an impedance of 4 Ohms and rated sensitivity of 91.5dB, many amplifiers should easily drive the speaker in a variety of listening environments.      

The prophecy9’s slim cabinets make for its small footprint. The cabinets are constructed of a balanced veneer on a high-density fiberboard (HDF) and can be finished in one of three sustainably sourced woods. My review sample was decked out in Blackened Walnut. 

At a relatively compact 40.5” high, 6.5” wide, and 14.2” deep, the 62-pound per channel prophecy9 will likely be aesthetically and physically integrated into most listening spaces. Four-millimetre binding posts, finished in high-quality satin nickel, accommodate single wiring. 

 Unboxing and Set-up 

The prophecy9’s two towers were destined for my dedicated 22’ x 15’ x 9’ acoustically treated listening room. They arrived in slender, but well-padded cardboard boxes. Attention to detail was very evident during the unpacking. The front of the box conveniently collapsed outwards, thus revealing that the goods were luxuriously wrapped in cloth dust bags. Floor spikes with floor-protecting cups were included in a separate box within the packaging.  PMC states that since the LaminairXes’ vent mass lowers the speaker’s centre of gravity, there is no need for the outriggers that were present on the twenty5.26i. 

Even at first glance, the prophecy9 gave away some of its non-conventional design elements. The tweeter and midrange drivers, which sit inside their waveguides, are set under small circular cages.  These provide additional protection for the drivers over and above the handsome, very well-made grills that magnetically attach to the speaker’s front. 

Also, the prophecy9 contains no port, either round, oval, or otherwise. Instead, at the speaker’s base are the transmission vent slats. Visually commanding, they form a curve where they meet the cabinet’s bottom. Fit’n’finish were commensurate of a speaker costing $13k.  

I initially positioned the two prophecy9 towers in roughly the same place as my reference Wilson Audio Sasha W/P Series 1 towers. After minimal fine tuning, the speakers were 94” apart tweeter-to-tweeter, 33.5” from the sidewalls, and 35” from the rear wall.  I auditioned the speaker without it’s grills. PMC states that using the grills will not materially affect the speaker's sound. The company states that it makes the grills from transparent fabric so there is minimal high-frequency attenuation. The company further states that it makes the grill's frames from thin material and chamfers their inner edges to minimise diffraction that would adversely affect the speaker’s off-axis response.   

 Surprising Power       

Listening to a new loudspeaker can be an exciting, but somewhat disorienting experience. No other component has a greater impact on the sound. As every speaker has a unique frequency profile, background details can suddenly be moved to the foreground and vice versa. For that reason, I have found that speakers usually require a period of acclimatization before their strengths and weaknesses can be properly assessed.   

As is the case with many speakers, the prophecy9 sounded somewhat veiled, recessed and diffuse straight out of the box. However, after approximately 10 hours, its key sonic characters emerged. One of those characteristics was a wide soundstage. When listening to the remastered version of “Yesterday” from the Beatles One (Apple 7243 5 29970 2 2 Qobuz), the opening bows of the string quartet at 0:22 swelled beyond the outer borders of the left speaker.  

The prophecy9’s ability to unwind layered and complex passages also impressed. This was demonstrated no better than on polyrhythms, where two or more conflicting rhythms are played over the same tempo. With “The Great Curve,” from the Talking Heads seminal 1980 release Remain in Light (Sire Records SRK 6095 Qobuz), these musical lines were well delineated from each other and easy to individually follow.    

The prophecy9’s sound began to stabilize at around 40 hours of use. At such point, it was evident that PMC’s design objectives for the speaker were realized. The bass and dynamic response that I heard clearly belied its compact stature. Indeed, this level of visceral impact from a speaker with dual 5” bass drivers was surprising, even if the transmission line does effectively become an additional bass driver. 

One of my go-to reference bass tracks is “Afro Left” from Leftism (Columbia CK 67231 Qobuz), the debut album of the British electronic duo Leftfield. Here, the mix of low-frequency percussion strikes and throbbing house rhythms were taught and agile, yet detailed and deep. Also, the track was reproduced with what seemed like very low coloration.       

There was also very little to criticize about the prophecy9 in the other areas. Treble never sounded bright or aggressive. However, there might have been a hint of roll-off or lack of emphasis in the very top octave. At least relative to my Wilson Sasha W/P Series 1 speaker, the prophecy9 did not constitute the last word in mid-range transparency and did not always provide pinpoint imaging. Though, at $27,900 USD when last available in 2014, the Wilson speaker is more than double the prophecy9’s price.   

While I would not describe the prophecy9 as overly “polite,” poor recordings often caused surprisingly little listening fatigue. When streaming “Jumpers” of the intentionally fuzzy and distorted psychedelic production of Sleater-Kinney’s The Woods (Sub Pop SP670 Qobuz), I enjoyed higher than usual volume without needing to turn things down. The contrasting styles of dual-vocalists Carrie Brownstein and Corin Tucker were audibly distinct and emerged with a strong center presence within the soundstage.

 Conclusion 

The high-end audio market contains many compelling choices in virtually every product segment. The $10-$15k floorstanding speaker space is certainly no exception, with many attractive options from both well-known and boutique manufacturers. What distinguishes the prophecy9 is its ability to “play big,” (i.e., produce a large soundstage and output powerful, articulate bass) despite its compact size. Given its other sonic charms such as a detailed yet liquid mid-range and silky treble, it's not only a compelling speaker for the discerning listener, but a must audition” for those with limited space in their listening room.   

PMC prophecy 9 Loudspeaker 

Price: $12,999 USD 

Warranty: 5 years with registration 

Dimensions: 40.5” H, 6.5” W, 14.2” D 

Weight: 62 lbs 

PMC 

Biggleswade, United Kingdon 

Website: pmc-speakers.com 

Associated Equipment: 

• Digital Source - Lumin T2 Network Player 

• Pre-Amp - McIntosh C500T 

• Power Amp - McIntosh MC402 

• Speakers - Wilson Audio W/P Sasha Series 1 

• Interconnects and Speaker Cables - Purist Audio Design Venusta XLR (x2) and Purist Audio Design Proteus  

• Power Conditioner - Audience Adept Response R12 

• Power Cords - Tara Labs The One (x2) and Audioquest Tornado High Current 

• Network Switch - English Electric 8Switch 

• Ethernet Cables - Audioquest Vodka and Cinnamon 

• Equipment Stand and Isolation Platform - Salamander Designs S30 and Ensemble ZOBRO 

• Acoustic Treatments - Vicoustic Mutlifusor Wood 36 (x4), Multifusor DC3 (x4), Cinemaround Premium (x4), Wavewood Ultra Lite (x2), Super Bass Extreme Ultra (x3), VicTotem Ultra VMT (x2) 

• Isolation Footers - IsoAcoustics Orea, Bronze, Indigo and Bordeaux 

• Grounding Boxes - Entreq Silver Tellus and Entreq Silver Minimus Infinity 

• Grounding Cables - Entreq Eartha Discover Infinity and Entreq Eartha Konstantin Infinity 

• Other Accessories - AudioQuest NRG Edison 20A Outlets (x2), iFi Audio LAN Silencer, Furutech Carbon Fiber 104D Plate and FI-28M Rhodium AC Plug, PS Audio Noise Harvester