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CnoEvil

The BBC Monitor

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13 hours ago, CnoEvil said:

Here's a paper about a Goodmans Maxim Loudspeaker ( a very small ls3/5 type speaker but not the BBC licensed version) written by Dudley Harwood from the research department, which sort of shows how the BBC thought about speakers: http://downloads.bbc.co.uk/rd/pubs/reports/1965-09.pdf

I loved the Goodmans Maxim I had in the early 80s.

Amazing to read about 8 watt power handling and other vintage measurements.  I remember the  boxes and the unique grille cloth but have no recollection of the sound. 

The paper looks like something from MI5 but then I suppose Beeb was ‘government’ in those days!

Edited by Nopiano

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Super Wammer
8 hours ago, wizmax said:

We will be carrying out a comparison between the LS3/5A and LS5/9 plus possibly the BC1 at Lurch's bake off on November 18th, should be interesting.

You can also add a goodmans Maxim2 to that list Robin as have just acquired a pair 😀😀

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8 hours ago, Nopiano said:

Amazing to read about 8 watt power handling and other vintage measurements.  I remember the  boxes and the unique grille cloth but have no recollection of the sound. 

The paper looks like something from MI5 but then I suppose Beeb was ‘government’ in those days!

I have a pair of these originals in their original shipping box and packaging. A surprisingly big sound and sound-stage for such a small box. I believe it was these original Maxims which gave the BBC the idea and impetus to develop the LS5/5a 

Edited by complin

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2 hours ago, complin said:

I have a pair of these originals in their original shipping box and packaging. A surprisingly big sound and sound-stage for such a small box. I believe it was these original Maxims which gave the BBC the idea and impetus to develop the LS5/5a 

Thanks  That’s quite a bit of history you own!  I can believe the sound.  I’ve invariably found that small speakers often work well in all manner of environments; it’s the bigger ones that cause problems.  Obviously the bass loses out somewhat, but the brain is remarkably good at filling in the gaps. 

The link with the 3/5a makes sense too, given the write up the Cno provides above. 

Edited by Nopiano

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Hi Cno,

I'm not sure if anyone has posted this before me, but there's also the Falcon Acoustics LS 3/5A which claims to be very close to the original 15ohm model. 

I found it a bit livelier than the Harbeth P3ESR, perhaps tweaked to make it more modern sounding.

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3 minutes ago, Singslinger said:

Hi Cno,

I'm not sure if anyone has posted this before me, but there's also the Falcon Acoustics LS 3/5A which claims to be very close to the original 15ohm model. 

I found it a bit livelier than the Harbeth P3ESR, perhaps tweaked to make it more modern sounding.

Other than mentioning it, along with a picture, I could not comment on how it sounds.

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And educational piece about the importance of listening from one of the BBC papers:

9 LOUDSPEAKER EVALUATION

9.1 introduction
The obvious and definitive means of evaluating a loudspeaker is of course by listening to it.
An expert listener auditioning known programme material can learn a great deal from a listening test.
If all of the sound balancers who use a particular loudspeaker declare it to be excellent, then by definition it is excellent.
In the author's experience at least, such universal approbation is rare.
Although a group of users in an organisation like the BBC usually show remarkable accord in their evaluations, they tend to use adjectives like 'woolly, ‘hard’, or ‘chesty’, and nouns like 'honk', 'quack', or ‘lisp’.
One can often hear what they refer to, but such quirks can rarely be identified by objective measurement, and are very poor guides indeed to any design modifications that might effect significant tonal improvements.
(Very rarely, complimentary expressions like 'clean' or 'uncoloured' are applied; perhaps one reason for the rarity of these is that a perfect loudspeaker should presumably have no perceptible characteristics of its own.)

What is required, of course, is a well-defined relationship between subjective peculiarities, measurable deviations from 'ideal' acoustic output, and oddities in physical behaviour.
A 'dreadful quack at 800 Hz' should be confirmed by a disturbance in the otherwise serene acoustic time-frequency-acceptability plot, and by an agonised writhing at 800 Hz to disturb the otherwise exemplary piston-like movement of the diaphragm.

Reality is otherwise.
'Good' loudspeaker drive units appear to exhibit just as complex mechanical and acoustic behaviour as 'bad' ones.
The author is currently engaged in a project to try to find some relationship between the subjective, acoustic, and mechanical facets of loudspeaker behaviour.
This has been undertaken in the knowledge that previous attempts during four decades have not yielded a final solution.
Results (positive or negative) will be published in due course.
Two reference works only are listed relating to this subject, each includes an extensive bibliography.

9.2 Subjective evaluation
Experience shows that comparative judgements of loudspeaker quality can be made more consistently than absolute ones.
An absolute assessment of a new design is something which emerges gradually out of weeks or months of use in control rooms.
Often, a pair of new loudspeakers sent out for 'field trial' will be received with cautious approval, yet returned after a month or two with a list of criticisms detailing points that have emerged only gradually from continuos use.
For comparative tests, a reference loudspeaker is of course needed.
This is provisionally selected during the early stages of commercial production as being a typical unit of acceptable quality; once production is well established, a new reference may be adopted as a clearer picture emerges of what is 'typical'.
In fact, at least three such units are selected in normal BBC practice, to provide a working standard for acceptance testing: a spare (which is carefully stored): and a standard by which the manufacturers can assess the consistency of their output, whether by listening or by measurement.
An established standard is also of course the only reasonable reference available in appraising a new design.

In listening tests, it is important that the listener should begin with as few preconceived ideas as possible.
For example, a look at a response plot may cause him, consciously or otherwise, to listen for some expected peculiarities. Normally, an A/B switch is provided, and the loudspeaker to be used as reference is indicated.
The loudspeakers are placed behind an acoustically transparent but optically opaque curtain, especially if any aspect of the units under test might be visually identifiable.
To help eliminate room effects, the test may be repeated with the loudspeaker positions interchanged.
If several units are to be tested, it is useful to include one twice — anonymously — to test the listener's consistency.
(Experienced listeners expect this.)

Finally, it is essential that the listener delivers his judgement before any additional information is given to him; not (one would trust) that he might 'cheat', but rather that he might re-interpret what he thought he had heard in the light of further knowledge.
Subsequent discussion may well prove valuable, but must be subsequent.

Formal tests involving a number of listeners may need further care, particularly if, as is likely, they permit less in the way of personal communication between subjects and test organiser.
Past experience suggests that a particular hazard is the use of descriptive terms whose meaning seems obvious to everyone, but which can actually mean different things to different people.

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  On 08/09/2018 at 07:42, Birdbrain said:

You can see I changed my mind...... Master Series had thin walls but very thick front baffle.

The weight of the SP9/1 was what repeatedly scared me off buying a pair. But what a fabulous sound. I made do with SP100 because I can lift them.

I do think you need that big woofer to create a sense of scale and weight. I don't think 8" woofer can do it. I haven't experienced a 10" woofer to see if they can do it. I rather think that 12" is the minimum, and when you look at the choice you are severely restricted these days.  SA active monitors with 8" bass unit were remarkable at what they could do, but it still wasn't like a 12" unit.

Back in the golden era of hifi, real enthusiasts had 15" Tannoys built into their living room walls. 12" was considered not quite the real thing, and anything less than that just wasn't serious hifi. It was the coming of the 2 cubic foot speaker (BC1) which made the 8" woofer such a standard

-----------------------------------------------

The BBC's LS-5/1a (by KEF) utilized a 15" (Goodmans) mid-woofer and two Celestion tweeters. Can't remember the tweeters' model # but they were the same as the Celestion units in my former BC-1 (1300, or something of the sort).

Prior to this model, the BBC also had used a monitor which utilized an 18" midwoofer. So prior to the use of main-monitors with 12" woofers, the Beeb used even bigger units.

Might have been nice if the hifi industry had cloned any of the "Beeb's" main monitors instead of emulating the albeit outstanding near-field monitors as the basis of speaker-systems purporting to be state of the art today.

Not sure how such a claim could be made for modern speaker-systems based on models which the Beeb themselves readily admit were models with limited abilities for close-monitoring, and secondary to their main monitors.

Nevertheless, there's no denying the fact that the LS3/5a and BC-1 (I forgot its BBC model #) are two of the most influential speakers the world has ever known, as it could certainly be argued that perhaps 95% of modern speakers are based on these two icons.

kef-ls5-1a-bbc-monitor-speakers-s-1a_1_eca1cec91bedf549224d6f13ffc883d9.jpg

Edited by curry49
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Resurrection of the original LS3/5a.  Not sure it’s worth £6,500 but probably a better investment than the same money in many other speaker brands. 

https://www.whathifi.com/news/falcon-acoustics-recreates-1974-bbc-ls35a-prototype-speakers

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56 minutes ago, Nopiano said:

Resurrection of the original LS3/5a.  Not sure it’s worth £6,500 but probably a better investment than the same money in many other speaker brands. 

https://www.whathifi.com/news/falcon-acoustics-recreates-1974-bbc-ls35a-prototype-speakers

The price is absurd, if we take into account the performance potential of the tiny toys, but they're only making 50 units, it's a collectors' item.

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