PMC twenty5 23i Loudspeaker Review

Small but perfectly formed

by Ed Selley
Hi-Fi Review

31

Highly Recommended
PMC twenty5 23i Loudspeaker Review
SRP: £3,850.00

Introduction - What is the PMC twenty5 23i?

The PMC twenty5 23i (hereafter 23i) is a compact two way floorstander that is the smallest member of the twenty5i range that made their debut at the 2020 Bristol Show (an event that by this point, feels chronologically closer to the fall of the Berlin Wall than today). It is effectively a floorstanding version of the 21i that we looked at last year.

There are a few reasons why this model has been selected for further attention. PMC makes no secret of the fact that this is the best selling model of the best selling range so, by extrapolation, this is the PMC speaker that is finding more homes than any other, so it makes sense to see why this particular model is ‘doing the numbers.’ It is also the most affordable (and yes, we’ll be covering the use of that word in the context of £3,850 in due course) model to make use of some extra refinements to the range that are not present on the 21i.

This is also a study in real world practicality. In many previous reviews for AVForums and elsewhere, I have made little secret that, used in most UK lounges, I prefer the performance of a standmount to a floorstander. I generally feel that they are easier to ‘dial in’ to most spaces and, when room boost is taken into account, can often provide a better low end performance than a floorstander. Can this particularly compact example of a floorstander go some way to redressing the balance?

Specification and Design

PMC twenty5.23i
The design is a clear evolution of what has gone before 

As the name suggests, the twenty5i range is an improved version of the twenty5 series that was in turn a heavy rework of the twenty series. The range line up has been the same since the largest 26 floorstander made its debut midway through the life of the twenty models. This means there are two standmounts, three floorstanders and a centre speaker. The floorstanders are interesting because they vary rather dramatically in size. The 23i and 24i are visibly variations on the same theme but the 26i is significantly different (and a veritable whopper to boot).

The 23i is mechanically identical to the 21i so we’ll cover off the internals in brief rather than completely wade through them again. The most important revision to the new models is an all new tweeter that uses a design pattern we’ve been seeing a fair bit of late, where an inner dome produces the very high frequencies and is complemented by an outer rolled surround that allows this small dome to be filled out and to crossover with the midrange driver.

In PMC's case, this is a very low crossover point indeed. The 23i hands over to the midrange driver at 1.7kHz, which is just about the lowest crossover point in a two way design I have ever encountered. The crossover that handles this is revised, with a new board and components being used to maintain the same basic slope as before. In keeping with most other PMC designs of late, this supports single wiring only. The 134mm mid bass driver that partners the tweeter is largely as it was in the preceding models where it was the major refinement of that generation, so it isn’t too surprising to find it carried over pretty much intact from there.   

PMC twenty5.23i
The pronounced rake on the cabinets aids time alignment

The first significant change in the 23i over the 21i is one imparted by simple physics. Like the vast majority of PMC speakers ever made, the 23i augments the output of the mid bass driver with a transmission line; a long duct that acts as an acoustic waveguide. In the 21i, this line is 5ft 6in long, whereas the larger cabinet of the 23i means it can become 7ft 8in. This in turn means that the 23i has a claimed low frequency roll off of 28Hz as opposed to 46Hz in the standmount. A key refinement of the transmission line principle also dates back to the previous generation. The ‘Laminair’ ports that the line terminates in are the result of flow modelling and are intended to ensure that the air leaving the speaker does so in a linear way rather than forming eddies (not least because these eddies become something that collide with one another if the port is producing regular bursts of air, say from a conventional bassline). It was a big step forward when it debuted so it’s no surprise to see it used here.

So far, aside from the presence of a second Laminair port and longer transmission line, the 23i and 21i are identical. The last big revision for the twenty5i range isn’t inside the cabinet but attached to the bottom of the floorstanders. During the development of the twenty5i range, PMC discovered their existing foot and spike arrangement was generating a resonance back into the cabinet that was affecting the performance of the speaker as a whole. As a result, PMC has designed a new set of plinth bars that are partially decoupled from the cabinet itself via deep foam washers. This quells the resonance and also gives the 23i greater imperviousness to sources of outside interference.

PMC twenty5.23i
There are two 'Laminair' ports on the floorstander

Aesthetically, the 23i takes the same ingredients as the 21i but the speaker that results is a better looking one than the standmount. Some of the detailing that feels fussy on the smaller cabinet are more effective on this larger one and the move of the effective but not terribly attractive Laminair vents to the bottom of the cabinet is a good one. The rear lean of the slim cabinet makes for a speaker that is small to begin with and manages to look smaller in reality. It is extremely well made and details like those new plinth bars and the custom terminals all help the PMC to feel bespoke and a little bit special.

There’s no escaping that the asking price of all this is £3,850 which feels quite high for a two way floorstander with a 134mm main driver. Even judged against other speakers that are made in the UK and Europe, the PMC can feel a little expensive. There are two things that I suspect need to be added to the conversation before I leave you to make up your own minds. The first is, as noted, the PMC is one of those things that looks better in the flesh than it does in pictures. PMC isn’t a company that does art for art’s sake but the design and finish on offer here is very compelling.

The second is that viewing the 23i via the specs is telling. A speaker that offers a claimed frequency response of 28Hz - 25kHz with benign impedance and sensitivity (a claimed 8 ohms and 86.5dB/w) in a relatively compact cabinet is not something that is that easy to find for significantly less than this. PMC's method of doing this can’t easily be done on the cheap but it does make for more compact and easy to manage design.

PMC twenty5.23i
Bespoke speaker terminals are a nice touch
 

PMC isn’t a company that does art for art’s sake but the design and finish on offer here is very compelling

How was the 23i tested?

The PMC has done an extended testing phase on the end of a Naim Supernait 3 and Chord Hugo2 and 2Go running as a Roon endpoint and a PS4 with all devices being powered via iFi Powerstation. They have then additionally seen testing on end of the Cambridge Audio Edge A running as a Roon Endpoint and the Marantz Model 30 Duo being assisted by AVID Ingenium Twin with SME M2-9 arm and Goldring Ethos, all being powered off IsoTek Evo 3 Sigmas and Aquarius mains conditioners. Material used has been FLAC, AIFF, DSD, on demand material from Tidal and Qobuz and on demand TV services and some vinyl.

More: Audio Formats

Performance


PMC twenty5.23i
An all new tweeter joins the existing woven mid bass 

The most important single thing to say about the way the 23i performs is that there isn’t a single retrograde step over what the 21i can do. The implementation of that new tweeter is no less effective here. In one generational revision of a speaker range, PMC has gone from a maker of speakers that really benefitted from some care in their placing to one that genuinely warrants the term ‘unfussy.’ So long as any attention is paid to toe in, the result is a truly superb soundstage. It extends beyond the outer edge of the cabinet and it makes the 23i hard to pin down in the space it creates. Crucially, it manages this without being diffuse or confused too. It’s deeply impressive.

In the 23i though it combines with a bass response that it seriously impressive for a cabinet that is 90 centimetres tall. PMC designs have never had a problem delivering low end shove but the debut of the Laminair ports was step change in how that shove was perceived. Before, there was always the faintest hint of a ‘whoomph’ effect as the bass strike was delivered- almost as if it wasn’t quite delivered at once. This is no longer the case. Revisiting Peter Gabriel’s OVO, a - frankly weird - effort of his from the turn of the century, the manner in which the 23i gets stuck into The Tower That Ate People is potent, heavy hitting and immediate. Everything starts and stops in the manner it should and it leaves those upper registers underpinned by a completely convincing weight and impact.

PMC twenty5.23i
The new plinth bars look smart and work a charm

The presentation of those upper registers is also impressive. There’s plenty of detail and the ability of the PMC to handle voices and instruments in a way that is entirely convincing is something that I haven’t been able to unsettle. Something that has become clear is that the 23i, perhaps more than its smaller relative, is a speaker you can listen through to the equipment that is driving it. With the Naim and Chord duo this means sensational drive and attack (with the three dimensionality of the electronics combining with the speaker to create something borderline holographic) but there is enough of an edge with them that the PMC can sometimes be a little hard with less well mastered material.

The partnership it formed with the Marantz Model 30 combo is a different story though. The Marantz devices are immensely civilised - sometimes a little too civilised for their own good. With the PMC though, the balance of the system that results is truly outstanding. As the Model 30 amp is over £1,000 less than the PMC, it does suggest that this is another speaker that can deliver excellent results without having to spend as much on the front end. This being said, it was continuing to show some extra facets to its performance with the Edge A, so if you want to use it to complete a more expensive system, it looks like it can do that too.

Crucially, the reason why you might want to do this is the PMC's speciality piece and the thing that might make the difference for many people between it being ‘good but expensive’ to ‘essential.’ We’ve already covered that the 21i is easier going about positioning than PMC models of old but the 23i adds a degree of flexibility about the room itself that is deeply impressive. In decoupling the PMC from the effects of its own resonance, PMC has also created a speaker that works in spaces where rivals - crucially even standmount rivals - can sound overbearing. Throw in other details like the cabinet venting forwards and you have a speaker that is getting on for ‘placement agnostic.’ I’ve tried a number of speakers in the upstairs system - for both running in and extended testing - and the 23i is the one that has delivered the best results of any so far.

PMC twenty5.23i
A truly accomplished all rounder
 

PMC has also created a speaker that works in spaces where rivals - crucially even standmount rivals - can sound overbearing

Verdict

Pros

  • Potent, detailed and invigorating sound
  • Very well made
  • Able to work in spaces that rivals cannot

Cons

  • Can be a little merciless with some partnering equipment
  • Fairly expensive

PMC twenty5 23i Loudspeaker Review

There’re two ways to look at this compact floorstander and those two perspectives will depend on your needs. In my solid floor lounge where speaker positioning is flexible enough to generally be optimal in all situations, the PMC is very good. It’s compact, handsome, well made and delivers a deeply impressive performance. The price feels a little high compared to some rivals that, in the same situation can rival it, and in terms of forgiveness, sometimes exceed it. It’s also close enough in price to devices like the Focal Kanta No1 - a speaker that offers capabilities that are a step change up again - that this needs to be factored in too.

If you’re reading this and your listening space is one where historically, speakers have been prone to bouts of unruly behaviour, this is a speaker that has capabilities that are significantly more impressive. This is a nigh on full range device that can be made to function effectively in spaces that will be beyond some standmounts to work in. This is PMC’s best selling speaker because it’s a Swiss Army knife with a transmission line. It isn’t cheap but it is very, very good and for this reason, the twenty5 23i comes Highly Recommended.

Highly Recommended

Scores

Build Quality

.
9

Connectivity

.
.
8

Sound Quality

.
9

Ease of Use

.
9

Features

.
9

Value for Money

.
.
8

Verdict

.
9
9
AVForumsSCORE
OUT OF
10

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