It’s an old adage – “you can’t squeeze a quart into a pint pot”. Or, in Star Trek speak, it’s Mr Scott saying, “Ye cannae change the laws of physics, Cap’n.” ELAC’s Line 300 series begs to differ. Because ELAC appears to do the impossible; real, useful bass out of a tiny loudspeaker, like the BS 312 tested here.

On the face of it, the BS 312 shares a lot in common with many ELAC designs, especially as the company has long promulgated the use of deceptively big sounding small speakers; this time, ELAC uses its JET 5 version of the Air Motion Transformer coupled with a 115mm AS-XR cone (also made in house by ELAC) and the rear-ported, single-wired loudspeaker is diminutive, uses a extruded aluminium cabinet and is best used on the dedicated stands designed to fit a range of ELAC standmounts. It’s small, surprisingly heavy and very well made. And none of this gets over precisely what the BS 312 is capable of, if you view this from a surface perspective.

Look closer. That JET 5 tweeter is a folded ribbon design, which works by folding the ribbon through a series of neodymium bar magnets. This is a high-precision process that is only possible in the hands of a specialist (a fraction of a millimetre out in one of the folds and the tweeter is virtually useless; it’s a job that requires a steady hand, a keen eye and infinite patience)… although the process is aided by robots. This manages to combine efficiency, power handling and break-up far outside the audible spectrum (around 50kHz) – the kind of trifecta of tweeter goodness. Variants on Oskar Heil’s device are relatively uncommon – Adam, Audiovector, Burmester, Mark & Daniel and more recently MartinLogan and Yacht Audio join ELAC on the AMT trail, and a few of those do so by buying

JET 3 tweeters from ELAC (he said quietly).

Then there’s that 115mm AS-XR cone made specifically for the BS 312, a clever sandwich arrangement with an outer layer of aluminium bonded to a paper cone in that distinctive ‘crystal membrane’ succession of triangles arrangement that adds rigidity and reduces resonance and colouration.

I’ve seen driver this on the test bench being played to unfeasibly high levels (the kind of levels that wouldn’t just break a bass driver, but immolate it!) without the slightest complaint. It’s ability to take power like it’s going out of fashion is what keeps this loudspeaker a contender when facing off against loudspeakers five times its size.

The crossover network sits on two small PCBs to the rear of the speaker, just in front of the single-wired terminal block. The crossover point sits high at 3.2kHz, which places it squarely at the top end of our most sensitive region of hearing, and the crossover itself bristles with air-cored inductors and high-grade ELAC-branded caps. Even the internal wiring looks above average.