PMC GB1

By Michael Wong

February 2007

PMC GB1 loudspeaker. $3299

PMC is the Professional Monitor Company, a UK company better known for state-of-the-art professional loudspeakers with products being used by leading performers and recording studios.

Using proprietary design and technology, the company joins the growing number of professional equipment manufacturers branching out into the domestic audio market.

Their first domestic speaker was the acclaimed FB1, a modestly sized, two-way floorstander. Over the years the range has expanded to include more floorstanders; above and below the original FB1, stand-mounts, home theatre speakers and even wall-mounted lifestyle type speakers. All are built in-house with various veneer choices, optional magnetic shielding for home theatre use and optional active operation (with Bryston amplification, which PMC distribute in the UK) on several models.

Supplied for review was PMC’s smallest floorstanding model, the GB1.

The petite floorstander

A two-way speaker system of petite (870mm x 155mm x 234mm hwd) dimensions, the GB1uses the same 27mm soft dome tweeter as the more expensive models in the range. It is accompanied by a 140mm doped mid/bass driver. All wrapped in a solidly built, finely finished cabinet.

Within is PMC’s Advanced Transmission Line bass loading pathway, exiting through a foam filled front port. According to PMC this method of bass loading improves resolution, reduces distortion, allows an even frequency response, greater efficiency, adds internal rigidity to the cabinet and produces bass of a level and quality unexpected from a small speaker like the GB1.

Two sets of good quality binding posts are fitted for bi-wiring. The speaker stands on a sturdy bolt-on plinth, adding stability to the speaker and providing a firm anchor for the adjustable spikes.

PMC claims a bandwidth of 29Hz–25kHz (no limits are specified, a startling omission by an audio company with “professional” as part of their name), moderate sensitivity of 87dB/1m/1watt and an easy impedance of 8 ohms. The GB1 shouldn’t be a problem for any competent amplifier.

Setup is straight forward: stay away from room boundaries (although the front porting permits closer proximity to the rear wall if such placement is unavoidable), use little or no toe-in, aim the speakers straight ahead or slightly behind the listener.

Bass transmission

The first listening impressions brought forth suspicions that the transmission line loading was not quite what it seems. Bass while adequate, was not the revelation promised. The quoted 29Hz may be possible but not within the usual -3dB limit. Using a trusty test CD and an analogue Radio Shack SPL meter I found bass roll-off with the -3dB mark at around 60Hz and quickly dropping thereafter. Respectable for the small 140mm driver but far short of the promised 29Hz low end.

Spatial presentation was good with the soundstage extending beyond the speakers’ lateral plane, depth was fair, height a little constricted. Full height can never be expected of a sub-one metre tall speaker and that is the case here. Images are reproduced in 5/8ths scale. There is good image focus and specificity, but not much space around the performers. Dimensionality is only fair, the presentation never reaches the holographic level where the speakers disappear.

Smooth operator

Tonally the GB1 is smooth with no obvious aberrations when the speakers are setup properly. The highs are clean and sweet but a bit dry and airless. With too much toe-in, there is a bit of treble lift that can be eliminated by reducing the degree of toe-in or aiming the speakers straight ahead.

Midrange definition was good; tight and precise with particularly good reproduction of vocals. Bass was not quite as extended or powerful as advertised but generally held a tune quite well. Moving the speakers closer to the back wall improved the quantity of bass at the cost of muddying the soundstage, and becoming a touch one-note touch in the lower frequencies.

However, the speaker does have a seamless top to bottom “cut-from-one cloth” disposition which makes it very easy to listen to, with the generally benign tonal balance doing a commendable job of masking the bandwidth limitations.

Dynamically the GB1 is best described as polite. Transients are softened. Missing is the immediacy and liveliness that makes music exciting to listen to.

A little disappointing?

Overall the PMC GB1 proved to be a little disappointing to listen to. The design is very pleasing to the eye, as is the high level of craftsmanship in the build. The speaker is easy to listen to but comes takes an overly bland approach to music reproduction. There are no glaring faults but also nothing to get excited about. It’s all very safe and polite. In this price range, where there is plenty of competition, the GB1’s are undistinguished.

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