BBC LS3/5a loudspeaker 1993 Harbeth version
The Rogers version of the BBC -designed LS3/5a appeared in 1975 and remained in production until early 1993. Other licensees have included Audiomaster (whose designer, Robin Marshall, went on to found Epos), Chartwell, RAM, Goodmans, Spendor, and Harbeth; the last two still manufacture the speaker.
In all that time, the design has been revised just twice. In 1988, the woofer's surround was changed from a springy Neoprene rubber to a more lossy vinyl compound and the crossover was redesigned, not to change the response, but to bring the production response window closer to target and to make the impedance a little less demanding. In 1990 a bi-wiring option was approved by the BBC, provided the performance in single-wired mode met the original specification. The $999/pair Harbeth version reviewed is only available in traditional single-wired form.
The 1992 Kinergetics Holdings takeover of KEF, who had supplied both drive-units and assembled crossover boards for the LS3/5a, brought the future of the classic miniature into doubt. But as fate would have it, news of the speaker's demise was premature. KEF intends to continue providing parts, and it is expected that Rogers will resume manufacture of the LS3/5a. The Rogers brandname was recently purchased by Hong Kong-based Wo Kee Holdings, but Rogers research and production remain the responsibility of UK-based Swisstone Electronics, which has owned the name since the late '70s.
The LS3/5a's tiny cabinet is constructed from real wood—birch—veneered with wood (apart from the front and rear), braced with solid beech strips, and heavily damped. The KEF B110 woofer/midrange unit, a 4.5", doped-Bextrene cone, is mounted from the rear of the cutout. The tweeter is the 19mm, Mylar-dome KEF T27, fitted with a perforated cover. Because the baffle is recessed, some form of diffraction control in the tweeter's acoustic environment was deemed essential; thick felt strips minimize the effects of reflections from the edges of the side, top, and bottom panels. The grille is acoustically transparent and is intended to be left on. (It can also be disturbing to see the quite large excursions the B110 cone makes on bass transients.) The complex 13-element crossover, carried on a large printed circuit board attached to the rear wall, is the heart of the LS3/5a. This can be tuned to compensate for variations in drive-unit behavior.
The Harbeth LS3/5a (serial numbers of units tested were H1650A/B) features the delicious midrange associated with the design. Voices sounded absolutely natural, with only a slight degree of extra chest tone on spoken male voice to reveal the highish-Q bass alignment. The old pair of Rogers LS3/5as were revealed as sounding nasal in comparison with the new pair. In absolute terms, however, there was still a trace of nasality present with the Harbeth version. There was also a touch of stridency in the middle of the violin's register that occasionally intruded on the music.
Surprisingly, considering the fact that both speakers were built to a standard specification, albeit 15 years apart, the Harbeths sounded considerably less tizzy in the high treble than my old Rogers. The ride cymbal in Miles Davis's "So What" from Kind of Blue (Super Bit-Mapped Sony CK 52861) was still very prominent, but there was more of a feeling that it was a physical instrument made from brass compared with the 1977 speakers, which emphasized the white-noise aspect of its sound.
Essentially, the '3/5a succeeds to its best extent where the original instrument's size is not too different from that of the speaker's baffle—voice, violin, clarinet, saxophone, etc. Piano and double bass suffer the most, being rendered as too small-sounding, lacking majesty. The speaker offered a smooth, buttoned-down sound that was almost always civilized. Its balance seemed optimized for lieder, spoken voice, chamber music, and, despite my comments above, large-scale orchestral recordings. There was enough bloom in the upper bass to give a feeling for the power of the full orchestra, something at which many small speakers fail miserably. You have to accept the latter having to be played at rather small-scale levels, however.
Lateral imaging was superbly accurate and stable, instruments and voices just hanging in space between the speakers. Depth was noticeable, but in this area the speakers were severely outclassed by the Harbeth HL-P3s, and particularly the Thiel CS2 2s.
The LS3/5a has never kicked big booty in the pace'n'rhythm department (footnote 1) and the latest version is no different. Bass instruments tended to sound a little fat and slow, while the ultra-polite speaker just doesn't get the idea of rock music at all. My acid-test track for bass pace is "Last Train Home," from Pat Metheny's Still Life (Talking) (Geffen GEFD 24145-2). Beneath the atmospheric brushed-snare back-beat rhythm and the lyrical electric sitar line, the bass player softly plays repeated eighth notes to define the chord changes. It is very hard for speakers with any hint of underdamping to correctly articulate this bass line; the LS3/5a was no exception, the track losing musical shape as a result.
The LS3/5a has never boogied and never will; it's just too polite ever to cut the mustard on rock, or even straightahead jazz. But for a classical music lover who has only a small room and perhaps keen-eared neighbors, the LS3/5a, used on a good pair of stands well away from room boundaries, is still a prime contender.—John Atkinson
Footnote 1: An early rival, intended to outperform the LS3/5a in this area, was the identically sized Linn Kan of 1980. Indeed the Kan did do so, having a beautifully tight, musically believable bass performance. But the price to pay was a colored, shouty midrange that for me ruled it out of contention.