There can be few more iconic loudspeakers than the LS3/5a. Designed by the BBC in the early seventies for use as a outside broadcast monitor it has been licenced by all manner of companies over the years and of late there’s been a resurgence in its popularity. There are various approaches to making an LS3/5a, Falcon Acoustics, for instance, has gone to the nthdegree to recreate a letter of the licence version by making replica Bextrene cones, others have gone the other way and sought to improve the design by using modern components and technologies, and of these Harbeth and Graham Audio are the most successful. Stirling Broadcast who hail not from Scotland but from Carmarthen in Wales (the name comes from founder Doug Stirling’s Scottish ancestors) has trodden a middle ground by employing Derek Hughes – the son of former BBC engineer Spencer Hughes (who, with his wife Doreen, also founded Spendor) – to design a LS3/5a with custom versions of off-the-shelf drivers while keeping true to the spirit of the BBC design. This is backed up by licencing from the corporation and based on a pair built by the BBC back in the day, so it has a 9mm birch ply cabinet with screwed-together front and rear baffles to replicate the lossy box philosophy that was developed by the Beeb at its Kingswood Warren research dept.
Stirling has been making a V2 LS3/5a for a number of years now with an eight Ohm nomimal impedance which is a lower than the classic 15 Ohms of the original design but makes much more sense in the context of today’s relatively high powered amplifiers. The low sensitivity of the design (83dB) was chosen in order to provide better bass, so it needs a bit of power to achieve real control and the eight Ohm impedance actually helps in this regard
According to Doug the V3 version of the LS3/5a is identical to the V2 in all respects except the crossover. The story goes that when Doug wanted to improve the V2, Derek Hughes said that the only way to do this effectively would be to build a no-holds-barred network. The result is large; just 16mm smaller all-round than the front panel. This was designed to reduce distortion to an absolute minimum and eke out as good a bass response as possible. According to Doug it’s the first time that components of such high quality have been used in an LS3/5a. This is, of course, reflected in the price, which comes in some £500 over that of the V2, which remains in production because not everyone will want to spend over two grand on a loudspeaker (strange but true!). The V3 also uses Tygan in place of the V2’s cloth for its front grilles
The LS3/5a has a very compact cabinet that is also an infinite baffle (sealed) design. This means that the bass is not augmented by port output and that tends to give a response that tails off much more slowly. The V3 is specified as having a lower response point of 75Hz which even for its size seems high but that is largely because of the sealed nature of the design.