The BBC LS3/5a monitoring loudspeaker is a true hi-fi classic. Apart from the QUAD ESL57, it’ is difficult to think of a loudspeaker that has been held in so much respect for so many decades.
The LS3/5a was designed as a compact monitor for use outside broadcast vans, but its performance outstripped the original brief and it found its way into monitoring suites throughout the BBC. On a visit to Bush House, shortly before the BBC World Service moved from there, I noticed dozens in use in studios and newsrooms throughout the building.
The BBC completed the design in 1972 and licensed its production to a number of companies from 1974 onwards, most famously Rogers. The loudspeaker continues to be manufactured by licensees today, although most of the companies now making it (with the honourable exception of Falcon Acoustics) use different drivers from the KEF B110 and T27 originally specified.
This unassuming, high quality monitor was quickly adopted by hi-fi enthusiasts for its natural, uncoloured sound and its glorious midrange. In 1976, UK magazine Hi-Fi for Pleasure featured a ground-breaking comparison between 30 commercially-available loudspeakers. In the articles, Martin Colloms subjected an experienced listening panel to a series of blind auditions, the conclusion of which was that the LS3/5a was more accurate than most of the tested designs including the Spendor BC1 and QUAD ESL57.
Critical to its performance is the very tightly-specified cabinet construction, which one writer estimates costs as much to make as many complete loudspeakers. We were curious about this and for a couple of years have been running a pair of Jordan Eikona 2 full-range drivers in genuine BBC cabinets, manufactured by one of the current LS3/5a licensees. The internal volume is an excellent match for the Eikona and we have been very pleased with the system’s performance; the sealed enclosure rolls off the bass below 85 Hz with an ideal 12 dB per octave slope. Combined with a good sub-woofer such as the BK XLS200, they make a superb, full bandwidth, stereo system.
We recently had the opportunity to test our Eikona/BBC cabinet speaker against a pair of original Rogers LS3/5as. These were serial numbers 357 and 358, so a very early production pair (over 43,000 were produced by Rogers and up to 60,000 have been produced overall). These were the 15 ohm version, which is generally preferred by aficionados over the 1980s 11 ohm variant. The speakers had been carefully restored and brought back to full specification.
The LS3/5as sounded wonderful; warm, involving and with an excellent stereo image. They couldn’t handle a lot of power but they certainly benefited from a good amplifier; their owner had been disappointed by the sound when originally purchased and only recently found out what they were capable of when he upgraded to a high- end amplifier.
We then switched to the Eikona/LS3 cabinet combination. Some adjustment was necessary as the crossover-free Eikona is 4-5 dB more sensitive than the LS3/5a – once that was done, we could enjoy the differences. The Eikona gave a broadly- similar, accurate sound but it was cleaner in the treble and throughout the mid-band. It also sounded quicker, with a wider and more focused stereo image. The LS3/5a owner preferred the Eikona’s presentation and commented that the midrange was noticeably better.
The LS3/5a sounded warmer in the bass and at first sounded as though it reached lower. This was due to the famous ‘hump’ in the LS3/5a’s bass response, a slight boost around 160Hz designed to give the impression of more bass than the design is truly capable of producing. By comparison, the Eikona/LS3 enclosure is more accurate in this region and rolls off at a slower rate. It doesn’t sound as beguiling on first listen, but it makes the system more amenable to tuning or the use of a separate sub-woofer.
It was a fascinating comparison. It may seem odd to compare a modern, full-range design with a 40-year-old speaker with a complex crossover, but the LS3/5a’s reputation for accuracy made it a very valid test. It is rare to have the opportunity to compare designs like this in what is basically the same, tightly-specified cabinet.
The Rogers BBC LS3/5a is a wonderful loudspeaker and we are pleased that it demonstrates just how well Ted Jordan’s Eikona 2 performs.