PMC fact fenestria

Hardware Review

PMC fact fenestria
Friday, November 19, 2021
floorstanding loudspeakers
Jason Kennedy

Historically at least priorities in audio have varied between the UK and the US. Americans hold that the loudspeaker is the most important part of any sound system, they tend to spend more on speakers than any other part of the audio chain. In Britain, ever since a certain Scotsman started preaching that the source is the most critical part of a system, this has been the accepted credo. There is an apparent logic in the notion that the more information is presented at the front of the chain the more music is likely to get out at the other end, AKA rubbish in rubbish out. Another way to look at this however is to consider which part of an audio system has the greatest potential for distortion, which is the hardest part to perfect. That is undoubtedly the loudspeaker. Nobody has been able to make a loudspeaker with a flat frequency response, that is one which reproduces all notes at the same volume. Some may have got close in laboratory (anechoic) conditions but the unpredictable nature of the end user’s listening room will always undermine that result.

The fact fenestria, PMC’s flagship loudspeaker, makes this point very clear by virtue of having so little distortion and tonal colouration of its own. It is the most transparent and even handed loudspeaker I have used in over thirty years of reviewing. It has also to be said that this is the most expensive loudspeaker I’ve been entertained by at home as well, but others have come close in that respect. It’s not the largest though, the KEF Muons were about the same size, but they arrived in one piece, the fenestrias are delivered in 10 boxes and consist of eight elements per channel. Which at least makes transporting their 80kg mass a bit easier but the nature of the design means it’s tricky to move once assembled.

PMC-Fenestria-Location-White-17.jpg

Starting at the bottom we have a substantial cast aluminium plinth, this provides anchor points for four machined stainless spikes and puts mass where it’s needed to give this 1.7m (5’7”) high loudspeaker stability. It also contains the crossover which is a pretty substantial fourth order affair with components placed such that there is the minimum of interference between them. PMC have gone to great lengths to isolate the different parts of the fenestria, to stop the energy from the bass system in particular from vibrating other elements and this extends to the crossover housing which has compliant connections to the loudspeaker above it. Connections for cables are made by six terminals for tri-wiring/amping and these are flanked by output adjusters for high and low frequencies to aid with room matching.

The next element is the lower of two identical bass cabinets, these have a pair of flat diaphragm, double layer carbon fibre drivers with a ‘rigid multi-cellular damped core’, which sounds like a foam filling in a carbon fibre sandwich to me. This is a technology found in PMC’s bigger studio monitors such as the mighty QB1 XBD-A but the first example on a domestic loudspeaker. The baffles that support the four drivers are made of synthetic stone, something like Corian, that provides a very rigid foundation and, unlike wood, is highly unlikely to vibrate at frequencies likely to smear the output.

fenestria-cutaway-with-air-flow.jpg

Each cabinet contains a specially treated transmission line that starts behind the bass drivers and escapes top and bottom via turbulence killing Laminair vents. The two bass cabs lock together and connect electrically simply by placing one atop the other in the appropriate orientation and twisting the top unit into place. This is a two man job but means that there’s no need for external cable jumpers on the back.

The curved panels that look like a styling or finishing element actually perform a critical task on the fenestria. They are compliantly mounted on multiple pins and act as tuned mass dampers (TMD), cancelling energy in the side of the bass cabinets. TMD is clever stuff that’s used to stop tower blocks swaying and improves aerodynamics in racing cars (where it is no longer allowed). Essentially a TMD reduces oscillation after an impulse by allowing a weight (in this case the panel) to counteract that oscillation and rapidly slow it down. The tuning is in the choice of the spring, here it’s the foam and rubber mounting between loudspeaker and panel.

MF-Render-Exploded-26-10-18(2).jpg

Midrange assembly and nest

The mid and treble drivers are mounted on the so called ‘nest’ which is made of machined aluminium and sits between the two bass systems and gives both drivers a totally open baffle. The nest is isolated from the rest of the cabinet with compliant mountings so that it’s won’t be vibrated by the bass cabinets. This is not something that’s been done before to my knowledge. Roksan produced a speaker (Darius) where the tweeter was held by springs and many have used compliant mountings between driver and cabinet but by putting the most critical drivers in their own space and mechanically disconnecting them from the rest of the box PMC have jumped the shark. The mid and treble drivers are both domes and are themselves decoupled from the metalwork for maximum isolation

The aim of the fenestria project was to build a loudspeaker “you’ll never hear”, which given its price is probably true for most, but they mean it has no character of its own; all you get is the sound, the music. This is ambitious under normal circumstances and seriously challenging in a full range loudspeaker, producing bass without making the enclosure vibrate is very difficult indeed but it doesn’t take long to appreciate that PMC have got closer than most to achieving it.

MF-side.jpg

Sound quality
The fenestria combines astonishing transparency with total musical cohesion, you get the micro detail, the dynamics and the thunder and you get a connection with the artist that is very rare indeed. This means you can hear just how good or bad each recording is and, for that matter, what the strengths and the weaknesses of the source and amplifiers are. I started out using the Moor Amps Angel 6 which sounded pretty good but swapping in a Bryston 4B3 did enhance matters like focus and timing quite clearly. The Bryston is rated at twice the output of the Moor which is certainly a factor in a speaker with 86dB (4 Ohms) sensitivity, but you can’t discount the fact that PMC’s engineers will have used Bryston amps to develop this loudspeaker.

I was also reminded of the point made at the start of this review, the fenestria makes a very good case for the loudspeaker being the most important part of a system because. It’s usually the weakest link, the source of most distortion, the fenestria produces so little distortion that it makes most other loudspeakers seem crude by comparison. Which does remarkable things for your favourite tracks as well as those you have never heard before. It produces the slew of vinyl effect for those with record players, where records start to pile up in disarray while you enjoy the one with the stylus in its groove. This speaker proves that you need a very good digital system if you want it to sound good enough to consider if there is decent vinyl to hand. That said it did make an iFi Pro iDSD DAC sound remarkably good, the Melco N10 supplying the digital stream certainly helped; the source is still important.

fact-fenestria-in-room.jpg

The fenestria does everything to a remarkable standard but it clearly excels in key areas such as evenness of balance at all volume levels, or linearity for short. Many speakers change tonal character with level, in some instance the mid can be recessed at lower levels which means that they sound better at higher levels, but more often the mid is prominent at lower levels which means the sound gets too forward and aggressive at higher levels. These PMCs give the impression of having a remarkably flat response regardless of volume, and that includes the bass. It took a little bit of experimentation with distance to the rear wall to get the bass balance right but once this had been established the bass was cleaner, clearer and more even handed than I have experienced before. In fact it was glorious, track after track revealed low frequencies that other speakers have never been able to define so well nor extend so far. I only fully discovered its capabilities in this respect when the amplification had been upgraded to Bryston 7B3 monoblocks which are good for 700 Watts each and allow these speakers to produce some astonishingly realistic results. It would of course be intriguing to hear them with more exotic amplification as that would certainly bring other qualities to the fore, the Brystons are a little buttoned up when it comes to emotional expression, but it’s encouraging to note that you don’t have to spend a fortune to drive the fenestria properly.

It did occur to me to ask why such a remarkable loudspeaker is not available in active guise, PMC’s other serious speakers in the SE range is available in active and passive forms after all. The reason given by PMC is that hi-fi enthusiasts like to use their preferred amplifiers, they might enjoy the power and control that active operation offers but would not be inclined to invest if they could not make changes in the future. In other words it’s a commercial decision by the company and you can’t blame them for it, well not too much anyway. It might save some ears too, this speaker is so clean that you can play it at pretty well any level without any signs of loudness, which means it’s easy to end up playing at dangerous levels over extended periods (partners/offspring/neighbours allowing), and active operation would only increase this potential.

F20-HF-Render.jpg

Tweeter assembly

However as I scrawled in my notes these are not so much speakers as epiphany machines, a means by which to travel in space and time to the control room or front row at the time each recording was made and appreciate all the work that went into it. I went through a few Little Feat albums on vinyl noting that Time Loves a Hero sounds a lot better than Feats don’t Fail Me Now, the latter having the advantage of Michael McDonald’s backing vocals. Both are compressed of course but the latter a bit less so, The Last Record Album which came out in between the two is the best sounding of the bunch, not least on the tear inducing ‘Long Distance Love’ which has some of the most gorgeous bass ever committed to tape.

What is also entertaining is that despite decades of listening to high end speakers and systems these PMCs unveil details that just weren’t there before, this was clear time and again, and when others came to listen they said the same thing about tracks they thought they knew inside out. The other common comment was how easy they are to enjoy, this comes back to the degree to which Ollie Thomas and his team have managed to eliminate of distortion in the fenestria. In practice it means that abrasive sounds like electric guitar, trumpets and saxophones are never any more aggressive or edgy than the artist/producer intended them to be. Jazz is a favourite genre but all too often the enjoyment is undermined by the tendency for speakers to harden up when presenting brass instruments, this doesn’t happen here and you can have your favourite horn player let rip without fear of their excesses being exaggerated. Good live recordings are the best of course, with this speaker they give you a vista into the performance that’s uncanny. The absence of any noise from the cabinets means that nothing gets blurred and you get to hear the event in full effect. The live factor also means that the musicians are fully focussed, communicating with one another and delivering a more cohesive and thrilling result than in a studio situation. 

PMC-Components1827a.jpg

Did I mention imaging? I shouldn’t forget that because this quality makes the music astonishingly real when it’s captured well. Fiona Boyes’ I Can’t Stay Here No More is so well recorded that you can feel her presence in the room, close your eyes and she’s right there. It’s quite uncanny, and I’m not just talking about the voice, the big kick drum and the guitar are there too, the drum in particular marking out the scale and character of the space it was captured in. What is also fascinating is the variation in imaging between recordings, many are much better than you would expect and only a few less so. This is a truly revealing loudspeaker, it won’t make bad recordings sound great but it will let you hear exactly what was put down in the first place. John Martyn’s BBC Radio 1 Live In Concert starts with Head & Heart, this sounds good enough to take you to the front row of the Paris Theatre in 1971, it’s sheer beauty is transfixing.

Finally it’s worth noting that the fenestria do voices as well as classic BBC designs, probably better. Rather a lot of high end speakers sound great with music but fall down with spoken word, this is not the case here as Lou Reed, Laurie Anderson, Gil Scott-Heron and Ishmael Reed among others made clear. Each is as clear and distinct as you could want with no sibilance or nasality. This comes down to the freedom allowed by the nest, it’s a perfect environment for midrange reproduction with no cabinet to vibrate or box to shape the sound. Stick one fenestria on its side and put four around the room and you have the ultimate surround system, all that’s required is a soundtrack worthy of such high resolution.

PMC-Fenestria-Location-Walnut-Tiger-15.jpg

That the fenestrias were able to achieve such astonishing results in a situation where they were really a bit too close to the listener (under 3m) with a system that is not in the same price league indicates that I have not discovered their full potential. What I did discover was a whole new degree of insight into my music collection thanks to a level of transparency and absence of distortion that is in the very top flight. This is not an inexpensive loudspeaker but there are plenty that cost more, whether any of them could compete is very much open to debate, the fenestria are a very hard act to beat.

Specifications: 

Type: transmission line, three-way floorstanding loudspeaker
Crossover frequencies: 3.8kHz, 380Hz
Drive units:
Bass – 6.5inch transverse-weave, carbon-fibre, multicellular-core piston driver
Midrange – 75mm rear-chambered, soft-dome
Tweeter – 19.5mm, Sonomex soft-dome, ferro-fluid-cooled driver with 36mm wide surround, neodymium magnet, micro custom chassis, silicone Aureole™ isolation mount
Nominal frequency response: 23 – 25,000 Hz
Nominal impedance: 4 Ohms
Connectors: 3-way Hex-Rhodium 4mm binding posts
Sensitivity: 86dB 1w/1m
Dimensions HxWxD: 1700 x 370 x 623mm including binding posts
Weight: 80kg
Finishes: tiger ebony, rich walnut, white silk
Warranty: 20 years

Price: 
£56,995
Manufacturer Details: 

The Professional Monitor Company
T +44 (0)1767 686300
www.pmc-speakers.com