Hi,
new member here but long time user of LS3/5as.
Basing any judgement of performance on an old pair of 15ohm LS3/5s is of little value because they will have drifted so far in performance, mainly in the 1Khz area.
For some reason this emphasis makes them very popular in the far east, and it is likely to be even more emphasised if used with a tube amplifier.
I personally have never heard a pair of 15ohms that I have thought good - I have never heard the Kingswood Warren prototypes but I have heard the pair labelled 001/002 that were the production version prototypes, now owned by Paul Whatton. Admittedly they imaged fantastically but they had the same 'slow' and ponderous bass of all 15 ohm versions I have tried.
Consequently I personally have owned several sets of 11ohm models and now have a pair of Stirling Broadcast (V3) ls3/5as as my main pair, in conjunction with their AB-2 bass extenders. I use them with Quad QMP power amps, a Music First Audio Classic V2 pre-amp and an Oppo 207 front end, with balanced connections.
The LS3/5a was a near field monitor for use in limited spaces, and therefore at low volumes, the sort of volumes where a lot of speakers haven't 'got going' yet. This is one reason why they are popular in the UK and the far east, with their smaller rooms.
I remember the Thomas Heinitz shop in London, where he sold classical music CDs mostly but also had an audio setup on demo in the main shop consisting of two systems 1) Quad amplification with Quad ESL63 loudspeakers and a CD player, and 2) a Denon mini system with LS3/5as and an AudioPro subwoofer.
He would first demo music (classic and some drum solos) on the Quads, and then he would demo the same on the much cheaper Denon/LS3/5a/AudioPro system. Then the customer would get his checkbook out and Thomas would accept a cheque for a system comprising a Denon mini system, LS3/5a speakers and an AudioPro subwoofer !!!
Note that the LS3/5as are a 'grade 2' monitor, according to the BBC designation (the 3), so they are not meant to be ultimate performers...
However the original design is inherently capable of better performance than this, and I believe the original KW prototypes demonstrated this, and the Falcon Gold version attempt to replicate this.
First off the prototypes had 'thin-wall' cabinets, which was a common design trait in BBC monitors and which was suppossed to lead to a 'lossy' cabinet. These cabinets had 9mm thick birch panels (with glued back panels?), whereas the productions versions had 12mm cabinets (for robustness reasons probably).
Personally I think this 12mm cabinet leads to 'compression' and a lot of problems in the performance of the bass driver - compare the performance of the B110 SP1003 in an LS3/5a compared to in a JR149 cabinet where it works much better.
Second off, the prototype crossover used much better components and careful matching of components.
Cicable produced an external crossover for the LS3/5a which used much higher quality, and bigger, components, whilst keeping the original LS3/5a response, and these yielded a huge (around 50db average in the charts present by Cicable) reduction in harmonic distortion.
My personal favourite pair are some Rogers 11ohm LS3/5as that have been transplanted to thin walled cabinets (from Stirling Broadcast) and use Cicable premium external crossovers.
I compared these to a grade 1 class monitor speaker I had at the time (Harbeth M30.1 - which are very LS3/5a like in sound - hence Alan Shaw produced an M30.2 as he doesn't really like the LS3/5a 'presence' sound). Obviously they couldn't match the bass performance but everywhere else my LS3/5as were slightly preferable, albeit very similar.
I say that they were transplanted Rogers, but I actually bought them from Stirling Broadcast as Stirling Broadcast bought the last of Rogers LS3/5a stock, and jigs, when Rogers went bust.
They then sold these, still badged as Rogers, and when that stock was depleted, entered into a sales agreement where they bought more B110 SP1228 and T27 stock from Kef (actually Celestion). At about this time Richard Allan also entered the scene and started buying drivers, and produced their own LS3/5a.
Then something happened with an agreement Kef had with Harbeth, maybe they transferred production of the drivers to them, I can't quite remember. Anyway, it ended up with the supply of drivers ending, which therefore left Stirling Broadcast in trouble.
(Just before this I had met Doug as I had bought two pairs of these final Rogers LS3/5as, and AB-1s, and then travelled down to his premises to audition an Rogers E40a tube amplifier, which he had also bought stock of but then got Audionote UK to 'fix/upgrade' to their originally suggestion design. I also bought one of his Corian plinthed Technics SP10mkII turntables...).
Stirling Broadcast then contracted Derek Hughes (son of Spencer and former runner of Spendor) to come up with a new LS3/5a version that used drivers that were actually available.
(Derek Hughes was also the designer of the Cicable crossovers I previously mentioned, and probably knows as much about passive crossover design as anyone, if not more. Derek now works a lot with Graham Audio and designed a passive speaker system at the Royal Opera House (
https://hifiplus.com/articles/a-night-at-the-opera/), where normally an active system would be used in such an environment. He also designed a similar PA system, using Crown amps, for Doug Stirling, but it was never for sale).
This was the V2 of the Stirling Broadcast LS3/5a, using Seas and Scanspeak drivers - the bass might have some extra doping on to mimic characteristic of the B110 Sp1003. I have a pair, and they are very respectable performers with a surprising amount of bass extension. Whereas the original LS3/5a drivers needed careful matching and varied in performance, the newer drivers are vitually perfectly matched out of the box.
Stirling then produced the AB-2 bass extender for the LS3/5a, which was another design by Derek Hughes - based on the AB-1s but with a larger cabinet and better crossover (Derek originally looked at my AB-1s in order to make a Cicable grade crossover but detemined that they had too small a cabinet for decent performance).
Recently Stirling produced the V3 LS3/5as, which have a different tweeter and also a crossover that rivals my Cicbles in size and performance, it's not quite as big as otherwise it wouldn't fit in the cabinet but it still has to be mounted on the back panel now in order to accomodate its larger size, which also means that the crossover is not as saturated by the magnetic field from the tweeter if it were mounted in the usual LS3/5a manner.
These V3s are about as good as my Cicabled pair for transparency, etc, but obviously have a far superior bass performance compared to my 11ohm pair that use the B110 SP1228s. I still suspect that the T27s are slightly better though.
Derek has since designed the LS3/6 for Stirling, and has produced many designs for Graham Audio, including their LS3/5a, LS5/9, and floor standing versions of them. I personally have not heard any of the Graham Audio speakers though.
So imho the best implementions of LS3/5as are the ones that have had Derek Hughes involved.
The current Rogers ones I believe have Andy Whittle involved (who ran the original Rogers at one point, designed the AB-1, and also runs Exposure) but I think they are a copy of the original and don't offer much more - apart from maybe a correct response as oppossed to the vintage ones around.
The Falcon ones are an authentic reproduction of the original drivers and cabinets, I would only consider that the Gold version are probably the only ones worth considering for ultimate performance as they are replicating the thin-walled (I think) cabinets and the better crossover.
If you after nostalgia then buy the originals and accept the poorer performace (the original 11ohm versions do not suffer this performance drift), but if you like the LS3/5a sound then audition the Stirling or Graham Audio (Chartwell) models, preferably with the Stirling bass extender or the floor standing models if you have to room.
I like the LS3/5a sound and cannot envisage ever changing from my V3/AB-2 setup, unless it is too swap in the Cicabled 11 ohm pair.
(It's a small world - my first hifi demo (at KJ in London) included Spendor SP2/2s, which were gorgeous but too big for me at the time, which were Derek Hughes first design. Later my Rogers E40a developed a fault, which Derek fixed but it turned out it is likely that his daughter or son-in-law probably built it in the first place as they were working at AudioNote).