its contemporary equivalent – the KEF LS50
Now, I appreciate that I’m describing a niche category within a niche category, but among audiophiles, the BBC LS3/5A is perhaps the most widely celebrated loudspeaker. And now I’m about to perpetuate the hullabaloo by blogging about it for a second time (my first Music & Miscellany post was entitled, Not The LS3/5A – you might like to read it for a bit of background). I do however have reasonable grounds I think for revisiting the subject in this post because I’ve recently been fortunate to spend some time with a loaned pair of new Rogers Classic 15 Ohm LS3/5As.
The background to the LS3/5A loan is that I was working on a magazine review of a monitor that is not only intended to play similar role as the LS3/5A, but also engineered by its designer (a big LS3/5A fan) to have a comparable set of electro-acoustic and subjective qualities (At the time of publishing this post, the monitor review isn’t yet published, so I can’t reveal its identity). So I felt it would be interesting to get hold of a pair of LS3/5As and compare the two monitors. It turned out that the designer of the review monitor has done a pretty good job of meeting his design aims, but the comparison also reminded me just what an unusual and exceptional little speaker is the LS3/5A – especially considering that it was designed in the mid 1970s. For the truly committed, a contemporaneous BBC R&D technical paper is available for download that describes the development of the LS3/5A. It can be found here.
Just as fascinating as the LS3/5A itself however is the story of its contemporary rebirth following the end of the initial, mid 1970s to mid 1990s, period of manufacture. During that time, the BBC granted manufacturing licences to Rogers, Chartwell, Spendor, Audiomaster, RAM, Goodmans, Harbeth and KEF. It’s estimated that upwards of 100,000 pairs of LS3/5A were made in total (the majority by Rogers). Among a particular niche in the audiophile community however, the end of that first phase of manufacture didn’t diminish interest in the LS3/5A, and the prices that used pairs in good condition could command began to rise alarmingly. So beginning in around 2008, a number of both established and start-up speaker manufactures took out new licences to begin manufacture again. One of the more recent new licensees and manufacturers is the present incarnation of the original Rogers company, now under different ownership, but lead technically by Andy Whittle, who was the last technical head of the original Rogers company. It was Andy who kindly loaned me the pair of new LS3/5As, and I took the opportunity on returning them to quiz him about what’s involved in accurately recreating an iconic product that was designed in 1975 and last manufactured around 1993.
The biggest issue that any new manufacture of LS3/5As has to face is that KEF no longer manufactures the B110 bass/mid driver or T27 tweeter, or anything like them (KEF, furthermore, no longer sell individual drivers). The materials, components, electro-acoustic parameters and manufacturing techniques required for both drivers are relatively well known however, so armed with component and material sources and a suitable manufacturing line, remanufacture of both drivers is perfectly feasible. And that’s what Andy has set up for his new LS3/5A. Both drivers are manufactured in Asia with components and materials carefully sourced to be as close to the originals as possible. There are however unavoidable elements of uncertainty inherent to recreating the drivers because the fine detail of their original electro-acoustic performance is all but impossible to establish with complete certainty. For example, any original bass/mid driver will be at least 25 years old, so the mechanical properties of its thermo-plastic and rubber parts (diaphragm and surround) will have drifted away from their original values. Similarly, it’s known that diaphragms for the T27 tweeter were vacuum moulded at KEF in white mylar sheet and subsequently spray painted black. Unfortunately, spray painting introduced variability between diaphragm batches, so the typical performance the original tweeter is hard to tie-down. The result of these and other variables is that contemporary characterisation of any original driver’s electro-acoustic performance, doesn’t reveal exactly how it would have performed when it was new. The only option for Andy and the other current remanufactures of the original drivers is to incorporate every snippet of historical knowledge to inform ideas on exactly how the original drivers performed in order to steer manufacture of new ones. Previously being technical head of Rogers is pretty useful in that respect.
With new drivers in production, Andy’s next challenge was the crossover assembly and cabinet. Fortunately, both are rather more straightforward to recreate than the KEF drivers. The crossover assemblies in new Rogers LS3/5As are manufactured to be as close as is possible to the originals, complete with the characteristic BBC style tapped transformer inductors. Capacitors and resistors are specifically selected to offer equivalent performance to original LS3/5A items and are mounted on a glass-fibre substrate printed circuit board using the same layout and spacing.
New LS3/5A cabinets are produced, as were the original items, in birch ply with beech corner fillets. Damping panels are attached to the inner surfaces. As with the original, the cabinet architecture incorporates a removable front panel to which the bass/mid driver is rear mounted and the tweeter is front mounted (with its well known, diffraction suppressing foam strips). The crossover assembly is mounted on stand-off pillars behind the tweeter.
The results of all this effort is a speaker that subjectively has all the magic for which the LS3/5A is so well known. In particular, its character through the midrange is extraordinarily natural and immensely seductive. The intention of the BBC designers who created the LS3/5A was to provide broadcast engineers with an accurate and reliable reference for radio and TV shows that, back in the 1970s, were predominantly inhabited by simply recorded voices and acoustic instruments – and it shows. If there’s something awry with the sound of a voice or instrument it’s immediately obvious. It’s this I think that most resonates with the audio enthusiasts who value the LS3/5A so highly; it speaks of the original, purist aims of hi-fi to reproduce music with such convincing accuracy that it transports the consciousness of the listener to the time and place of the recording.
The interesting question that’s left however is why? What is it, in electro-acoustic engineering terms, that makes the 46 year old LS3/5A such an extraordinary performer? To my mind it’s a list of things; closed-box format, skilful driver design and integration, and clever tonal voicing, but at the top of the list I’d put the LS3/5A’s immensely rigid but properly damped cabinet structure. Along with writing previously in this blog about the LS3/5A, I’ve also written before about how cabinets contribute to the sound of loudspeakers and how I think the phenomenon is no longer given the attention it deserves. My recent experience of a new LS3/5A does nothing at all to change that opinion.
Music and Miscellany 
Hi Phil,
First off, I am a big fan of your work both at SoS and here. You have a refreshing subjective approach and follow the science of measurement. Thank you for that balanced ethic.
I am a long time audio addict and once owned and operated an audio shop back in the 70’s and 80’s. We were very early adapters of the BBC designs and were the number two LS3/5a retailer in the USA. We sold every version of the licensed design, both 15ohm and 11ohm versions, with the exception of the Goodmans. The best of that era, in my opinion, was the 15ohm Rogers. As good as they were, the Spendor BC1’s, Quad (57) ESL and Quad 63 were better. The only issue that we had with the LS3/5a was that they were just not great for late night listening. If you turned them down, you turn them off as the dynamics collapsed. They had a specific envelope of level that they worked well in and did’t scale down nor up. The kings of this were both Quad models and full range folded horn systems.
I am recently retired, downsizing my system and I am very curious on your thoughts about the current LS3/5a offerings by both Rogers and Falcon compared to an active option. Your review of the Neumann KH150 got my attention. The other interesting active options to me are the PSI models 17 & 21 along with a few in the Genelec line.
There was a very interesting article in a DIY German publication a number of years ago where they benchmarked a variety of DIY cost no object monitors with that of the original Rogers 15ohm LS3/5a driven by rather esoteric tube electronics. The Rogers won out by a large margin. They then compared everything with the Neumann KH120a. They were confounded as the Neumann’s were the top choice by a small margin over the Rogers. When measured, the profile of the Neumann looked almost identical to the BBC counterpart, 80hz bump and all. It was somewhat bothersome to some of the audiophile types assembled as they could hardly believe that an old BBC design, let alone an active pro monitor could win out. That article has been in the back of my mind since. So, as you can imagine, your perspective of these two contemporary monitors have my antennas up.
Any additional thoughts on this would be appreciated. Tkank you, again, for your sharing your experience and work here and at SoS.
Best regards.
John Shepherd
(former shop: Middleton, Kemp & Shepherd, Anaheim, CA USA)
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Hi John,
My name is Scott Lewis, I bought a pair of the ROGERS LS3/5A’s from you guys back in 1980. I still use them as my daily speakers. I believe your partners name was Norm Middleton?
I found myself reading about these speakers today on the internet and they were talking about using the serial numbers to date and authenticate, so I looked at mine and both speakers are blank, or extremely faded. Is there anywhere else inside the carbonate that I could locate the serial numbers?
Norm( if I’m remembering his name correctly) also sold me a Quad amp, preamp and tuner along with a turntable, but that brand name eludes me.
He tried to sell me the Quad speakers but they were out of my price point at the time though I did pick up a pair l years later, my ex wife hated them because of the size.
For some reason I recall coming to you house one time, maybe to have you repair one of the Rogers, not sure. Santa Ana area?
Anyway, I digress. Hope you are doing well.
Regards,
Scott Lewis
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Hi Scott,
What a surprise to hear from you. First off, I am doing well. I am retired from my day job as a Public Health/ Health Care Administrator. I have been in the Pacific North West for many years since we closed the HiFi shop. Norm is still down in the Riverside area and he too is retired but from the audio industry.
I am happy to hear that you still have and are enjoying your Ls3/5a’s. They, along with the QUAD’s and the Spendor BC-1’s are three of the all time best domestic loudspeakers regardless of price. They really have lasted the test of time. The QUAD electronics were really standout products as well. Are you still using them?
More than likely, you probably took your speakers to Norm’s house or maybe a tech that we were affiliated with, Charlie Olander.
If you cannot read the serial numbers on the foil label, you might be able to date them by the serial numbers on the woofers. A good source for help would be the folks in the UK at either Falcon Acoustics or the new Rogers company. The Falcon people are great if you need replacement drivers, parts etc. The designer of their in-house manufactured drivers was the engineer/desiger of the original drivers at KEF. Their products, including the 15ohm crossovers are to exact original specs and can be interchanged with the originals. They have a web site that you might find interesting.
There is a group out of Hong Kong that run a web page and blog on the Ls3/5a. They are obcessed with the details. You will just have to search them out. There is a site, the unofficial Ls3/5a site or something like that which has a lot of info. It may very well be the same people out of Hong Kong.
Good luck with your research. It is nice to hear from you. Enjoy your Rogers Ls3/5a’s. They are simply classics without peer in their category. We sold a lot of them. I was told that we sold more of them than any other dealer in the continental US market. I guess that we recognized that they were something special back then.
Take care….let me know how you fare with your search.
Best regards,
John
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Hi John & Scott!
I’m really pleased to have connected you through my modest blog efforts but the way things are I have to approve your messages before they become visible (hey, I love the feeling of power, but it’s probably not the most practical of arrangements). If you both message me with your email addresses via the contact form here (https://musicandmiscellany.com/about/), I’ll reply to both of you so that you then each have the other’s email address.
And Scott, I could also put you in touch with Andy Whittle – the guy behind the reborn Rogers company (and actually the last Technical Director of the original Rogers company). Andy will be able to help you with all sorts of info on LS3/5A bass/mid drivers and perhaps identify the serial numbers.
John, sorry I’ve not got around to replying to your original comment. I’m simply stretched too thin at the moment to get to everything. One thing I have done though is review the Neumann KH120 II – the review is out in Sound On Sound this Thursday (18th May) I think.
Cheers
Phil
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Hi Phil,
I just wanted to run this question by you. In retrospect, what are your final observations or preferences between a 15 ohm Ls3/5a (Current Rogers or Falcon), the Neumann KH120 ll and Neumann KH150 for home use? It is just impossible to do any sort of comparison. As I have indicated before, I am experienced and lived with the original Rogers Ls3/5a’s a number of years ago. Any additional insight would be appreciated.
How is your large monitor project going?
Again, many thanks for your work here and at SoS. I wish you a happy and safe new Years.
Best regards,
John Shepherd
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Hi John,
To be honest I’m not sure the LS3/5A and the KH120/150 are realistically comparable. They’re just so different in terms of objective performance and subjective character. The LS3/5a has a distinct personality that many (me included sometimes) find really engaging and works really well at low volumes in domestic spaces. The KHs are far more neutral and revealing in contrast and go much louder, but that can all mean they are a more challenging listen if the material is flawed. Not sure I’d want a pair of LS3/5As in a busy studio setting, but I’d probably be very happy with a pair in a small study with a glass of wine and BBC Radio 3 playing.
Big monitor? Do you mean this: https://strattonacoustics.com/
Design is fun but traditional hi-fi sales channels are, errm, challenging verging on dysfunctional.
Happy new year to you too.
Phil
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