The BBC LS 3/5a are real classics. I have friends that love them, and they are still sought after. The main strength is that the sonic balance and non-fatiguing qualities. The fidelity is not so good, but it is a trade off between the balance of fatiguing or fidelity. The only way to get a better balance is using a good full range driver which is hard to come by. This is why I am working on the driver part.
If you want one, get a genuine ex-BBC pair or perhaps one of the last KEF high-sensitivity versions.
perhaps cos these appeared after my time at KEF so I don't know what the BBC think of them.
ROTFL 😛
Sorry. This is perhaps the funniest thing I've seen on DIYaudio 🙂
Yes, the old ones are what I am talking about. Really have not heard much about the new ones coming to market. KEF did a new one which they configured to be co-axial (forgot the model, but it is in the news quite often. There are something's they seemed to have done well, but did not seem to sound like what I would expect from such design.
Actually the Jordan drivers are among the better full range implementation, but still needs some teaks to make the sound cleaner, neutral and more transparent. The Alpairs were based on the same technology.
Actually the Jordan drivers are among the better full range implementation, but still needs some teaks to make the sound cleaner, neutral and more transparent. The Alpairs were based on the same technology.
@Kgrlee: Can well believe it. As a fresh grad I did apply to BBC research, made it to the last 5 but in a way lucky I didn't get in as the closed it 2 years later. The whole 'swayback' shape of the LS3/5a never sat well with me so when BBC put their research papers online it was interesting to note that the original pair were completely flat, a feat never matched by any of the production units. In fact looking at some plots they were all over the shop. Why the BBC stuck with them for so long is a tad strange.
When BBC closed down its london news centre after the move to salford all the old studio stuff was auctioned. 20 year old, unmatched and well shagged 3/5a were selling for £600 a pair then appearing on ebay for £999. I believe idiots were buying them at that price.
And if you luck out (dome tweeter in waveguide) and can get LR4 acoustic in the treble with just a single capacitor then why not!
Never auditioned active diamonds, but the passives were remarkably good for a small box. Sometime must listen to the LS50s, but have no space for an additional system right now.
When BBC closed down its london news centre after the move to salford all the old studio stuff was auctioned. 20 year old, unmatched and well shagged 3/5a were selling for £600 a pair then appearing on ebay for £999. I believe idiots were buying them at that price.
And if you luck out (dome tweeter in waveguide) and can get LR4 acoustic in the treble with just a single capacitor then why not!
Never auditioned active diamonds, but the passives were remarkably good for a small box. Sometime must listen to the LS50s, but have no space for an additional system right now.
Modulus-86: Composite amplifier achieving <0.0004 % THD+N.
One of the difficulties is getting drivers to be in certain specs. Generally factories accept 2db variation requirement. But I did get inquiry to accept more deviation above 10KHz. Depending on design, there are many variables that need control, I can imagine it to be quite difficult in those early days of LS 3/5a. But they do have certain groups that like them, just like the vinyl records, and there are aspects to like about them as well. You also have groups that like tube amplifiers, which I also can appreciate the qualities not available in solid state amplifiers, they key is when designing for the better is to try and audibly identify what parts of quality you feel each design's strengths are as well as weaknesses, and try to rinse the cause through different types of measurement, then find a solution to see if there is a better balance.
Usually the solution is not found in existing textbooks and papers, this is when you are really treading new territory, where the true excitement of development work is.
One of the difficulties is getting drivers to be in certain specs. Generally factories accept 2db variation requirement. But I did get inquiry to accept more deviation above 10KHz. Depending on design, there are many variables that need control, I can imagine it to be quite difficult in those early days of LS 3/5a. But they do have certain groups that like them, just like the vinyl records, and there are aspects to like about them as well. You also have groups that like tube amplifiers, which I also can appreciate the qualities not available in solid state amplifiers, they key is when designing for the better is to try and audibly identify what parts of quality you feel each design's strengths are as well as weaknesses, and try to rinse the cause through different types of measurement, then find a solution to see if there is a better balance.
Usually the solution is not found in existing textbooks and papers, this is when you are really treading new territory, where the true excitement of development work is.
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I think you miss the point. NOT ONE production pair of LS3/5a met the specs of serial numbers 001/002 and everyone who has heard them says they sound way better than any of the 12+ variants that appeared over the years.
Few mortals have heard what they are supposed to sound like.
Few mortals have heard what they are supposed to sound like.
Modulus-86: Composite amplifier achieving <0.0004 % THD+N.
I know, most brand them LS 3/5a for marketing. Though I have never looked at the crossover design, I think the driver specs are probably the most uncertainty. The drivers today certainly are not going to match the drivers of the first development units, then you have a later discovered preference known as the BBC dip which is also an additional mystery. Whether later LS 3/5a had modified crossovers to accommodate new drivers or target market preference group is also unknown to me.
How they really sound like may not be as important as most may think because the real value is the line of configurations which lead to the design and measured performance, if you have not record of those. The configuration in a single report is of much less value.
I know, most brand them LS 3/5a for marketing. Though I have never looked at the crossover design, I think the driver specs are probably the most uncertainty. The drivers today certainly are not going to match the drivers of the first development units, then you have a later discovered preference known as the BBC dip which is also an additional mystery. Whether later LS 3/5a had modified crossovers to accommodate new drivers or target market preference group is also unknown to me.
How they really sound like may not be as important as most may think because the real value is the line of configurations which lead to the design and measured performance, if you have not record of those. The configuration in a single report is of much less value.
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Modulus-86: Composite amplifier achieving <0.0004 % THD+N.
Well, the LS 3/5a is of no interest to me technically, why would I want to spend time on it?
Was not even my preference back in my young audiophile days.
Well, the LS 3/5a is of no interest to me technically, why would I want to spend time on it?
Was not even my preference back in my young audiophile days.
As it so happens, I have inside knowledge from both the customer (Beeb), drive unit supplier (KEF), both good & bad LS3/5a 'makers' and the machinations thereof. Some of this is in the public domain and some of it is most certainly NOT 😱
Also Mark Dodd who did the LS50 which I've never heard or seen.
.. none of this is relevant to Mod86 except how to make an active speaker powered with a single PP3 sound like one. 😀
Also Mark Dodd who did the LS50 which I've never heard or seen.
.. none of this is relevant to Mod86 except how to make an active speaker powered with a single PP3 sound like one. 😀
I should imagine there are a lot of untold stories given what is published and the questions that raises! If you are ever in UK let me know and I'll ply you with beer for some of the unknowns 🙂
It's OT but valid in terms of discussing how it makes active more affordable.
It's OT but valid in terms of discussing how it makes active more affordable.
I would be interested in BBC recording setup. All BBC recordings seem to have inverted polarity.
Among my collection and from a Hong Kong magazine report, it seems like about 50-50 of the labels go each way. The most audible different is spacial image focus and bass punch.
They were recorded in the northern hemisphere. I guess you are in the southern hemisphere.
I can understand the concept of "correct" polarity for a single sound source, recorded with a single microphone. It is not really possible to define a single "correct" polarity for music with multiple instruments, voices or microphones.
It is quite obviously detected to all of the people I demonstrated it to. The only question I would get is "how would you detect wrong polarity without comparison?" But you can try for yourself. Even a store owner 70year old can hear the difference.
With experience (and a suitably good phase behaviour system), wrong polarity is self evident, and reversing polarity (restoring correct acoustic polarity) is confirmation.
There is complication in that indeed some sound sources are recorded in wrong polarity wrt to other sound sources.
In this case with recordings with intelligible/prominent vocals, I select polarity for correct vocal reproduction.
In other music the vocals may be diminished/obscured and I may/may not select polarity to set say correct bass reproduction.
With correct acoustic polarity acoustic level is louder/stronger.
Vocals actually sound distorted and reduce prominence in the mix when played in wrong polarity.
With spoken word and nature recordings acoustic polarity is mission critical for correct reproduction of direction and depth.
With suitable speakers and suitable programme, 3D presence is reproduced, with sounds coming from behind the speakers and from behind the listener.
Dan.