PMC twenty5.26

Hardware Review

PMC twenty5.26
Monday, July 3, 2017
floorstanding loudspeaker
Jason Kennedy

In an age when a 50inch television is considered normal it is increasingly rare to find anyone who has loudspeakers that are much bigger than baked bean cans. And yet who ever reached nirvana watching the telly! I know that Fargo is pretty good but transcendant it is not. We know that this is all wrong, that a decent pair of loudspeakers is as important as food and shelter if one is to escape the madding crowd and ascend to a higher plane, but not everyone has experienced astral travel as a result of great sound. Ignorance is not bliss when it comes to music.

PMC know this as well, that’s why they make the twenty5 range, it looks very similar to the more affordable twenty series but there are some important differences that put these speakers above and beyond, not only beyond their stablemates but many other aspirational loudspeakers too. The biggest twenty5 model is this the twenty5.26, which stands just over a metre high without its lovely one-piece stainless spikes and weighs in at 25 kilos. It’s the only model in the range to sport a dome midrange (below), a 50mm example that can’t be all that different to the one in the fabulous Fact.12. The bass driver in this three-way is a 6.5inch, long throw design with PMC’s g-weave material for the cone. This is a resin bound glass fibre that is extremely light and stiff in order to deliver the power handling that PMC requires.

The company’s background in professional audio means that they expect all their designs to deliver high sound pressure, especially the pro models, as I discovered at the launch event for the QB1-A last year. The largest speaker that PMC makes has four 10 inch bass drivers and nearly 5000 Watts of class D active drive. It delivers monster level without so much as a hint of distortion, which means it doesn’t sound ‘loud’ but your vital organs start to disintegrate if you're not careful. A state of affairs that confused the younger engineers attending the event who kept wanting more level because they associate volume with a type of distortion that sounds good. I had to abandon the room after the first request for more, and it wasn’t the last.

 

 

The connection between the QB1-A and the twenty5 series is the Laminair vent, this is an arrangement of fins in the mouth of the transmission line that is said to allow easier airflow through it into the room. The first speaker that designer Ollie Thomas tried this on was the QB1-A, a design that is required to produce considerably more bass extension and SPL (sound pressure level). Strangely although Laminair allows greater ease of airflow it also puts more pressure on the back of the drive unit at the other end of the line, making the bass driver’s life harder, hence the move to g-weave.

Laminair had its beginnings in Thomas’ experience in F1 where drag is a key aspect of a car’s performance, less drag equals more speed. You get similar strakes or fins at the back of an F1 car so he tried the same at the end of a transmission line, PMC’s preferred loading method, and found that improvements to bass quality and distortion made this a significant leap forward. Fans of other PMC designs have therefore been pestering the company to revise the rest of the range, but what do they go and launch at Munich High End, an amplifier! Still the Cor does look good and has tone controls, I’m looking forward to hearing one.

 

 

The twenty5 series also differs from other PMCs by virtue of having single wire terminals, very nice custom made, rhodium plated, copper examples but just the one pair. This is an approach that certain other brands have long preferred but it’s still unusual. What PMC considers more important is that these and the crossover behind them are non magnetic, The polished stainless steel back panel is designed to minimise interaction between components, which surely could have been achieved with a wooden plate, I guess it wouldn’t be as shiny though. The Q-Acoustics Concept 500 has two rear plates made of an acrylic and stainless sandwich, they consider rigidity to be the key. It takes all sorts.

The twenty5.26 sits on a pair of brushed stainless bars that bolt on to the cabinet and have threads for the aforementioned spikes, the extra width gives the cabinet a bit more stability but doesn’t make it look ungainly. Indeed with its sloping profile the 26 looks like it has grown up in a strong wind, they must get extreme weather up in Biggleswade!

Sound quality
Placement wise the twenty5.26 needs a bit of room around it for best results, not acres to be sure but I gave them 35cm to the rear and twice that to the sides which seemed to work. Their bass output is pretty significant but well controlled and fires forward so you don’t need them in the middle of the room like some rear ported designs. I started with an ATC P1 (150W) amplifier that proved more than adequate on the muscle front, with sensitivity at 86dB (8 Ohms) this isn’t a particularly tough load but you do need a bit of grip to get the best out of PMCs in my experience. And the better the amplifier, the better the result.

 

 

This is a precise and revealing loudspeaker, every tweak and cable you change is obvious, it is more forgiving than a Fact.8 thanks to extra bass power but in terms of detail resolution the two are very close indeed. It encouraged a lot of notes about the clarity of attack and decay with a variety of types of music. The definition of micro dynamics is particularly good, it’s easy to hear the way a pianist weights different notes and how long the pedals are depressed or otherwise. Javier Perianes superb rendition of the works of Manuel Blasco de Nebra (Piano Sonatas 1-6 Op.1, Harmonia Mundi) is totally engaging as a result of this ability to draw you into the finer aspects of the playing. But this doesn’t get in the way of the bigger picture, with Kraftwerk’s live version of ‘Radio-Activity’ (Minimum Maximum, EMI) the power and shape of the sound is front and centre while the crowd noise and music fill up the end of the room completely, it’s full immersion in a room engulfing fashion. I ended up contrasting Ethernet cables with this track and was able to hear pretty big differences, with Chord’s Sarum T delivering a lot more shape and depth to the sound compared with the Melco usually employed. I also had my first listen to the rather nice Audio Technica ART1000 moving coil via the twenty5.26 (of which more soon). This has extraordinary speed alongside low level resolution that’s to die for and beautiful timing.

That’s what I love the Fact.8 for, its timing, and this PMC is not a lot different. The balance is a bit warmer so it doesn’t sound quite as nimble, but that’s the nature of deep bass, it is not fast but as long as it stops and starts at precisely the right time the result is equally engaging. And the extra extension you get brings a depth and realism that’s utterly thrilling. It’s not just weight, it’s shape as well, with certain bass notes on the Kraftwerk there are clear graduations in the bass that give it a depth and presence that’s not normally apparent. Then there’s ability to separate out different instruments in a mix, with any piece of music that combines a variety of instruments and voices it’s very easy to hear exactly what each is doing, especially in situations where one normally masks another. This is obvious on Bugge Wesseltoft’s ‘Sharangati’ (OK World, Jazzland) where a rather thick sounding bass guitar can often be lost behind a full bass drum, but not here. This clarity contributes to superb coherence, all of the musicians are locked in sync and the track really chugs as a result, so mushc so that it gets hard pressed to listen analytically after a while.

 

 

It’s probably a combination of factors but the presence of a midrange driver definitely contributes to making this a more revealing and dynamically capable loudspeaker than the smallest standmount in this range, the twenty5.23. The Twenty5.26, is highly transparent in an effortless fashion, and able to reveal the smallest things in the music as easily as the fundamentals. It seems to be more neutral than its lookalike in the twenty series too, the twenty.26, which is not nearly as similar as it appears. This big twenty5 is very hard to describe because it has so little character, as a result it reflects the quality of each recording you play with considerable precision. In many ways it’s a speaker for all seasons, I tried all manner of music from electronica to Vivaldi and enjoyed all of it, heard new detail in most of it and rediscovered just how good some of the performances are. Separation of the different instruments and voices in any piece of music is very strong, it has the ability to open up the soundstage so that each sound source can strut its stuff. This is very dependent on the associated source and amplifier of course, it’s one of the areas that improves as you upgrade and tweak the system, but it’s nice to have a speaker that let’s you hear what’s going on.

I tried these PMCs with a Plinius Hiato, Metrum Forté and a Marantz PM-10 amplifier and got a good result with all of them, the Hiato took top honours (it is also top dollar) but all four were able to control them without difficulty. In fact the Hiato proved a beautiful partner for the twenty5.26, the dynamics, detail resolution and timing were beguiling, and when this was combined with the Rega RP10/ART1000 analogue source it became very hard to tear myself away. What I like about this PMC is that it is transparent without any sense of fragility, it engenders a confidence that whatever you send down the cable will come out very close to the way it was originally intended with nothing discernible in the way of colouration or veiling. There are more transparent loudspeakers of course but few if any near this price that make music in such convincing fashion.

When I had the twenty.26 I was loathe to let them go but ultimately came down in favour of the Fact.8 because of its timing, the twenty5.26 bridges that gap, it does bandwidth, resolution and timing, I wonder if they’d notice a swap!

Specifications: 

Type: Floorstanding, three-way, transmission line loudspeaker
Crossover Frequency: 400Hz, 4kHz
Dimensions HxWxD: 1040mm 40.9” (+20mm spikes) x 192mm 7.6” (275mm incl. plinth bars) x  439mm 17.3” (+15mm grille)
Drive Units:
LF - PMC twenty5 series 6.5”/140mm long-throw g-weave cone with cast alloy chassis
MF - PMC 50mm twenty5 series, dome mid-range
HF - PMC/SEAS 27mm twenty5 series, Sonolex fabric soft dome, ferrofluid cooled
Effective ATL™ Length: 3.3m 11ft
Frequency Response: 27Hz – 25kHz
Impedance: 8 Ohms Input
Connectors: One pair 4mm binding posts
Sensitivity: 86dB 1W 1m
Weight: 25kg (55.1 lbs) ea.
Available Finishes: walnut, Amarone, Diamond Black, oak

Price: 
£7,350
Manufacturer Details: 

The Professional Monitor Company Limited
T: +44 (0)870 4441044
pmc-speakers.com