The LS3/5A (each element pronounced separately, without the stroke) is a small studio monitor-loudspeaker originated by the BBC for use by outside broadcast vans to ensure quality of their broadcasts. The speaker concept set out transparent and natural sound as the goal, and the achievement of the end result is widely acknowledged.
The BBC granted licences to a small number of British firms, who first manufactured the product in 1975. The product underwent a change in 1987 due to consistency issues in manufacturing, and again in around 2003 when original parts from KEF ran out. Upwards of 60,000 pairs of the speaker have been sold. Reviewers have recognised its enormous importance as a bookshelf design.
Those obsessed , fanatical and genius BBC engineers seeking s[eaker perfection as their Holy Grail , was to get the human voice as natural and clear as possible ....it was the national broadcaster. Then came the refinements to get the rest of the midrange “right” (that’s where 90+% of the listener sounds reside), and the rest of the speaker development spectrum followed.
History
The LS3/5A is a commercially produced loudspeaker driven by the need of the BBC to monitor and assess broadcast programme quality. It was derived from the LS3/5, which was conceived and developed by the BBC Engineering Department in the early 1970s, when it was under the stewardship of Dudley Harwood. (NOTE: he founded HARBETH)
Having found no commercially produced small loudspeaker that met the requirement for naturalness and sonic neutrality, the BBC specifically set out to design a speaker to achieve natural overall sound quality and good dynamic range for monitoring broadcasts in tightly confined spaces.
As the BBC broadcasting unit was about to order another batch of the monitor, it was found that the supplier had modified the drive units, meaning the LS3/5 design had to be fundamentally revised.[The BBC’s Designs Department was called upon to adapt the product in light of the supply changes. Modifications were made to adapt to the new drive units and deal with the altered resonance pattern, and the LS3/5 became the LS3/5A.
The BBC then licensed the product to a small number of private sector companies. Production began in 1975. In 1987, as a result of reassessment of the product due to consistency issues in the manufacture of the mid–bass driver, the drivers were modified and the crossover changed. The overall impedance of the crossover fell to 11 ohms from the original 15 ohms.
The various official versions of the LS3/5A from various licensees sold in significant numbers in its life of over a quarter of a century. Sales estimates range from 60,000[3] to 100,000 pairs.
In the tail end of the 1990s, due to the parts being discontinued, the 3/5 had technically reached the end of the road. Some licensees continued to make small numbers of speakers, for a while, using re-manufactured parts. However, Stirling Broadcast, one of the last batch of licensees, completely redesigned the product based on the audio signature of the original, and launched the LS3/5A v2 with the full endorsement of the broadcaster in early 2006.
In 2014, production of the 15 ohm version of the LS3/5a with a full BBC Licence was re-commenced by Falcon Acoustics using re-engineered versions of the original drive units and the original design BBC crossover all produced in-house.
Best of the contemporaries: Harbeth released the P3ESR.
https://www.stereophile.com/standloudspeakers/harbeth_p3esr_loudspeaker/index.html
https://www.youtube.com/hashtag/harbeth (Imperfectly perfect -.... my last speaker)
https://liquidsound.ca/product/harbeth-p3esr/
https://forum.audiogon.com/discussions/harbeth-p3esr-vs-the-new-xd
https://www.the-ear.net/review-hardware/harbeth-p3esr-40th-anniversary-standmount-loudspeaker