AudioSmile Little British Monitor

These compact speakers punch well above their weight — and you can build them yourself!

Back in the deep, dim and distant past, loudspeaker kits were a big(ish) thing. British hi‑fi speaker brand KEF (Kent Engineering & Foundry, if you ever wondered) in particular did pretty good business with their KEFKIT 1, 2 and 3 and Constructor Series. The kits included drivers, passive crossover assemblies, internal foam, cables and connectors, and all the various specialist hardware items required. All the customer had to do was build a couple of cabinets and they’d have a pair of high‑performance KEF speakers for somewhat less than the equivalent finished retail price. But as time moved on, intense competition pushed the price of high‑performance speakers inexorably downwards, and speaker kits faded away. So, when I came across the Little British Monitor (LBM for short), a compact active monitor that’s available in both finished and kit form, I couldn’t resist having a go at the latter.

The LBM comes courtesy of a company called AudioSmile, founded by audio designer Simon Ashton. Simon has a track record in a variety of audio engineering contexts and the LBM is by no means his first loudspeaker design. Simon’s experience with speakers is clearly apparent from the genuinely unusual and interesting electro‑acoustic engineering that can be found within the extremely compact dimensions of the LBM.

Although Simon describes the LBM as ‘little’, ‘tiny’ might have been more appropriate, because the LBM truly is minuscule. This will mean that while the LBM offers great benefits should you be looking for something easily portable or to fit on a small desk, its compact dimensions and very small bass driver will also have significant implications for the low‑frequency bandwidth and maximum volume levels achievable.

My decision to build and review the kit version of the LBM added some complexity to the review process. In particular, it was important that the finished speaker I listened to and tested was built to the appropriate standards, so along with submitting a kit for review Simon also kindly supplied a finished pair of monitors. This arrangement also meant I had to build just one monitor, and while generally it’s the case that building one LBM makes building a second one more straightforward, pairs of LBMs are configured as an active primary (in which all the electronics and amplification are installed) and a passive secondary. These are connected by a 2m cable that terminates in a locking multiway connector. And rather than clutter the guts of the review with stories of speaker building, I’ve covered that in a separate box.

Little Boxes

An LBM is 208 x 123 x 137mm (HxWxD), which puts its internal volume somewhere around 2 litres. By way of comparison, a Neumann KH120 MkII nearfield monitor (which I’d consider compact) has an internal volume of around 6 litres. The LBM cabinet is predominantly constructed of 12mm thick, CNC‑machined birch plywood, and it incorporates some steel bracing bars that both tie the two side panels together and provide some extra rigidity in the bass/mid driver attachment. The finished cabinets feel very solidly put together. The pre‑made version of the LBM is finished in a black textured metallic paint with exposed plywood edges on its front panel and bass/mid driver rebate. It looks pretty smart, in a slightly homespun sort of way.

The drivers employed in the LBM are a nominally 75mm (3‑inch) diameter bass/mid unit and a nominally 25mm waveguide‑loaded tweeter. The bass/mid driver is an OEM component from US company Dayton, manufactured in China. It’s a genuinely interesting driver featuring a neodymium‑iron‑boron magnet motor system with, very unusually, an underhung voice coil and copper shorting ring. The driver diaphragm is aluminium. For its compact dimensions the driver offers an impressive ±4.6mm linear diaphragm excursion.

The tweeter is one of the “unusual and interesting” elements I mentioned earlier. This is because, while the world of OEM drivers isn’t remotely short of cost‑effective high‑frequency driver solutions, Simon chose not to go down that route. Instead, for the LBM, he engineered a composite tweeter using an OEM full‑range inverted‑dome driver of the kind that might be found in a computer or ultra‑compact desktop speaker, and combined it with a custom waveguide and ‘lens’. The reason for doing so was primarily to create a driver able to operate with a high‑pass crossover filter around an octave lower than the 3kHz typically necessary with a conventional low‑cost tweeter. To operate down to 1.5kHz, as the LBM tweeter does, both a very low fundamental resonance frequency and extended diaphragm excursion are necessary, and those characteristics simply aren’t available from any compact and inexpensive OEM tweeter.

Simon’s need for the LBM tweeter to have extended bandwidth and a low crossover frequency arises from his desire for the system to offer well‑controlled vertical dispersion through the crossover region. At higher crossover frequencies, off‑axis path length differences from the...