Transmission line bass loading distinguishes this compact floorstander from most of the competition

Since its beginnings in the late 1980s, PMC has grown into a major player on the UK speaker scene, focusing on ProAudio customers and the more upmarket hi-fi sector with its ATL (advanced transmission line) speaker systems.

Although it’s no larger in width and depth, the £1,525 per pair GB1i is a little taller than the other two-way models that use small bass/mid drivers. The reason has all to do with the transmission line bass loading technique, which squeezes a carefully damped 2.4m line into the enclosure volume behind the main driver, by folding it twice and terminating it with a large port at the front near the floor. Besides forming the acoustic loading, the vertical partitions that create the line also add beneficial stiffness to the enclosure.

The speaker has a solitary small 140mm cast frame bass/mid driver, with a 95mm doped, flared profile paper cone. This allows the enclosure to be kept fashionably slim, a point emphasised by its vertical edges. The enclosure proper comes fully veneered in cherry, oak or maple, while a neatly shaped, black-painted MDF plinth comes as part of the package, which increases the stability footprint and provides good accommodation for the floor-coupling spikes.

The tweeter has a 27mm ‘Solonex’ fabric dome and takes over above the 2kHz crossover frequency. Two pairs of terminals cater for bi-wiring or bi-amping if desired.

Sound quality

The GB1i is essentially a fine all-rounder, with the benefits of fine two-way coherence, as well as timing and good speed. It attracted particular praise for its bass reproduction and showed few signs of weakness right across the band.

The notes created a strong impression that the panelists gradually grew to like its sonic presentation more and more during the course of the programme. Bass weight, detail and control all attracted praise and the listeners warmed to the combination of a slightly forward upper midrange, alongside some presence restraint that characterises this speaker.

The small main driver and good bass extension together inevitably restrict the power handling, especially when replaying vinyl (which tends to contain unwanted subsonic signals), but this seems unlikely to prove a practical limitation under most domestic circumstances, except perhaps for those with a taste for particularly heavy material and high-level replay.

Stereo images were well formed and portrayed with a generous soundstage and fine central focus, though height and depth both seem a trifle constrained.

Dynamic expression is unexceptional and one might have wished for a little more grip and drama, but the actual dynamic range is very good and any box-related colorations seem very well controlled. The top end is also essentially sweet and well judged with good overall coherence, so the speaker as a whole delivers plenty of fine detail about the music and the musicianship.

This pretty little speaker leaves little opportunity for criticism. The bottom end is definitely better than most of its size and while the midrange could perhaps be smoother, decent sensitivity and an easy load all help make a persuasive mixture.

LIKE: A fine all-round performer with superior bass delivery
DISLIKE: Could be smoother through the midrange
WE SAY: Power handling is somewhat limited, but this floorstander has a delicate sound

Origin: UK
Type: Floorstanding loudspeaker
Weight: 10.5kg
Dimensions: (WxHxD) 155x870x234mm
• Advanced transmission line bass loading
• Shaped MDF plinth extends footprint
• Choice of three real wood veneers
• Large port at  base front
• Twin terminal pairs for bi-wiring/-amping
Distributor: PMC Ltd.
Telephone: 08704 441045