The Twenty series – developed to mark PMC’s 20 years in the speaker business – are proving extremely popular round these parts. The elegant Twenty.24 is one of the best floorstanders (reviewed in issue 86) you can get for the money, but what if you have neither the money nor the room to house a set of tall tower speakers?
The PMC Twenty.21 is at the opening end of the Twenty range. It’s the smallest bookself in the series, a two-way transmission line design that has a very narrow front baffle and a five-degree back-swept demeanour for both style and time alignment. The Twenty series is something of a departure for PMC. Like the Fact range before it, the Twenty series is the first to be designed from the ground up as a domestic model. It’s voiced more for home audio instead of studio requirements, with an accent on ‘musicality’ as well as common elements like low distortion.
Twenty is a ‘clean sheet’ design, although it builds on PMC’s strengths. No components used in the Twenty series feature in any other PMC speaker. Pete Thomas, chief designer of PMC, is a strong supporter of the transmission line, a method of channeling bass through what is effectively a labyrinthine and damped tunnel. This bass emerges at the large vent at the front of the loudspeaker effectively as a second bass driver. Not only does this mean extra bass for any given loudspeaker drive unit size, it gives a constant air loading so the driver is less likely to distort at any given frequency. PMC’s Advanced Transmission Line is the latest and greatest expression of this design.
The drivers are PMC specific. The 27mm Sonolex soft dome tweeter is a design specially made for the company by SEAS, while the M13 140mm bass driver is also made to PMC’s spec. It’s a doped paper cone, built into a cast alloy chassis. These are not earth-shattering speaker driver designs, just good, solid and well-built drive units, built to a high standard. They are connected via a 24dB/octave crossover, which ends in bi-wire terminals.
The cabinet itself is also good, solid stuff; 18mm thick MDF to be specific. With all the internal chambering that goes into a transmission line (also 18mm MDF), the speaker has no need for internal cross-bracing, and the cabinet is very dead to the knuckles. It comes in a choice of three wood finishes and a rich ‘diamond black’ gloss, which really looks the part. The grilles are magnetically attached so if you decide to go grille-free (and you probably should), there are no ugly holes staring back at you.
Even the stand is thought through properly. The top-plate is actually two top plates, with some constrained layer damping material (technical term: goo) between them. It’s spiked at the bottom and comes with two hollow uprights; the front can be filled, the rear has holes for cable management. The stand is not a mandatory element in the PMC design, but it’s an ideal (and reasonably elegant) first choice.
The thing is, this is an easy loudspeaker to love. It’s small enough and efficient enough to drive to make it an neat fit into some relatively humble systems in some exceptionally small spaces, yet throws out a deceptively big sound for the size of speaker. They perhaps lack the sort of bare-boned transparency of the studio-derived PMC models, but that only tends to be better for making these loudspeakers more popular in the home.
It’s also a very forgiving speaker in terms of positioning and room treatment. Yes, the more obsessive you are about these things, the better the end result, but the speaker isn’t that fussy. Just get the speakers mildly toed in, level and a foot or so from the rear wall, things will be peachy. The stands allow a degree of fine tuning of sound by filling the front-most pillar with silver sand or kitty litter, a big room needs that front tube perhaps a third full, a box room almost two-thirds full, but even this has a lot of wiggle room. And as for loudspeaker cables, simple is often best. This isn’t the most system-revealing loudspeaker out there; if you are a wannabe CD player designer, this speaker won’t tell you all you ever wanted about the sound of the player, just the tracks being played through it.
Perhaps as a consequence, it happens to tick most of the boxes for all the sub-genre of hi-fi enthusiast. The ‘PRaTtlers’ will like it because it ‘times’, keeping the tempo of music structurally intact, while ‘absolute sounders’ will praise it for its ability to resolve the voices and the ambience in a choral piece. Those who are determined to see music replay drawn down to a science project will like the way PMC’s pro background has not been compromised in the 21, while those wanting loudspeakers built by elven folk will find something to love. OK, so if you are so militantly attached to one of these audio personality types that you find yourself constantly reliving the “Are you the Judean People’s Front?” scene from Life of Brian in forums, you’ll probably put the Twenty.21 second on the list, and those in love with horns, electrostats, single-ended triodes or the endless swapping of boxes will find another option. But this was never the speaker for the audiophool; it’s a good, honest loudspeaker that makes an excellent sound that will appeal to the maximum number of people today. Easy to say, hard to do and even harder to find in the wild.