BBC LS3/5, LS5/8, LS5/9, LS5/12A monitors

[A.S.]

We're off walking in the Northumbrian hills today, so I have much time to relive and add to my comments.

One thing to be aware of which has direct bearing on your comments about the presence dip on the early Harwood-designed Harbeths (HL1, Mk2 etc.) is this: Dudley Harwood, unbeknown to me at the time I took over Harbeth, was a member of a fundamentalist Christian faith. He lived a simple life, and was disinterested in the trappings of modern consumer life. He was prohibited by the rules of his group to take any interest in entertainment, and that apparently included music of any and all types. Now, you may ask how a world-renowned loudspeaker engineer could evaluate loudspeakers, unable to listen to music on them - it is difficult to comprehend what work-arounds he used. But certainly speech recordings, which were permitted, became critical to his evaluatory process. Without the formal ongoing feedback from BBC users who you mention, it must have been very difficult for Harwood, now ex-BBC and running Harbeth, to be sure about what was a correct speaker response balance bwteen bass, mid and top. If you recall, in one HFC, he was criticised for having set the tweeter level too high (Mk3?) and this was surely a direct consequence of working alone, and not listening to music and natural hearing loss with age.

However, judging, controlling and shaping the energy in the presence region (say, 1-3kHz) and the position of musical performers front-back (z-plane) is much easier in stereo, and with music. Also, again this did come up in conversation with Harwood and is in the transcript, I asked him 'what is the purpose and function of the so-called Gundry-dip where energy is reduced in the (typically) 1-2kHz region'? His answer was unequivocal .... "to mask coloration in the polypropylene cones'. This was the first admission that even though he was the father and patentee of PP cones, they had known deficiencies - quite an admission.

The BC1 had a bextrene cone, where coloration in broadly that region was ameliorated with a thick coating of PVA 'dope'.

[audiolab]

Wow, that is absolutely fascinating!

I have memories of those first HL1s, but they belong maybe in a new subject thread.

thanks again, I appreciate it.

[A.S.]

Yes do start a thread on the original Harbeth HL Monitor from 1977 - known now as the Mk1.

Just a few more thought that came to me today. The world is full of would-be artists and would-be loudspeaker designers. Daubing paint on canvass and trying to recreate reality looks, and conceptually is, simple. But when you actually try and do it yourself it proves to be exceptionally difficult. Yes, you can make an image but held up to reality is it photograph-like or abstract? What Harwood and his predecessors set out to do with the oil paints available at that time (cone technology) was to create a high precision sonic photograph but using only oil paint. That requires immense skill and sensitivity as you'll know from visiting the National Gallery. At its very, very best, an oil painting is indistinguishable from a photograph.

We should also consider the window in history that Harwood et al occupied. I can see this very clearly now. Harwood began his engineering career (with the National Physical Laboratory) shortly after WW2 and then transferred (or perhaps was seconded) to the BBC. His generation would have been highly regimented partly by the social structure of the time, and partly by the wartime mentality of rank, file and order. Discipline at work, in project management and interacting with superiors and subordinated would have followed precise social norms, down to the way he as department head announced himself on the phone in the stentorian tones of "Harwood here" - it still makes me nervous to recall that! The entire development of those classic BBC monitors was a direct consequence of the wartime and social environment, and no other combination of events would have produced them. They are, for what they set out to be, the most perfect embodiment of research and development thoughtfully directed at a precise goal, their own mini-Saturn V.

Now, each generation believes, understandably, that it can do better. Doubtless within the BBC as Harwood was moving towards retirement during the 1970s (with his polypropylene patent under his arm) there was a feeling that he represented the old school. Old in a rigid wartime deference for tradition and process and old in maintaining a scientific disinterest in the then booming hi-fi industry outside the BBC. And old school for his (explained) aversion to pop music. 1979 returned a Conservative government and the 1980s saw a significant rise in UK economic activity and a rediscovered global self confidence. This was a time of pushing against social boundaries, self-expression, a redistribution of money and influence in society away from 'the establishment'. Harwood was the establishment. I suggest that Harwood's successors itching to put their own ideas into practice merely reflected the climate of the 80s. If you look at British education policy you'll see the exact same oscillation from generation to generation. A quasi-military structure like the post war BBC needed strong generals, hard even feared senior engineers who asked searching questions of their subordinates and who only deal in facts not opinions. Take away those generals and a new sort of engineering democracy results.

My position - I mean, Harbeth's position - is that when I first, as a boy, became aware of the research and products to come from Shorter and Harwood imaginations, they inspired me hugely. They presented this complex business of painting in sound in a way that was so eloquent, so thoughtful, so beautiful as a work of science that it had truth and integrity shining from every word. It was all so logically presented. Observation A, then B, conclusion C from which D was postulated and E proven. I - I mean Harbeth - have no need or desire to waste our time and your money trying to wholesale improve on a concept which, for what it is designed to do, was, is and will remain perfect.

What we can do - and this would be fully approved of by Harwood - is to concentrate on specific details (such as the unique RADIAL cone) and to take those components to a higher performance level. But the underlying 'BBC monitor concept' is just such a perfect execution of the 'most performance for the least cost' that I believe that in one hundred years will be the only current electromechanical transducer system still giving pleasure making sweet music in a cold, sterile fully digital world.

[mhennessy]

To cover the point about 5/8 (or 5/9) frequency balance etc.. Actually, I was at Research Dept. with an overseas visitor just two weeks ago. We did some filming in the archives (in HiDef) and this included a piece to camera by me going through a card index box which has been set aside for me containing hundreds of original frequency response pen-charts of 3/5a, 5/8, 5/9 etc. etc..

Hello Alan,

Funnily enough, I was there last week. I didn't have the time to take a decent look through that box file, but noted what you mentioned in the full post above... This file was located in the loft along with the collection of reference loudspeakers and a large sheaf of documents that would be the basis of a fascinating documentary!

When there, did you note a pair of speakers that used the LS5/9 drive units in a smaller enclosure? It was a sealed box IIRC, and made from birch ply with no veneer. Can you shed any light on these - were they an experimental pair?

For what it's worth, I confess to actually quite liking the LS5/9s - although I'm aware of (and would agree with) the problems which you have documented in the various threads on this forum... And I'm also very aware that I'm in a relatively small minority, especially within the BBC!

Best regards,

Mark

[A.S.]

Yes, I know those prototype speakers and we have pictures and videos of them and the loft to be covered in a future videos for the Harbeth archive. Clearly they were prototypes of a speaker that would, in Harbeth terms, be a somewhat condensed Monitor 30. Tidying and condensing the Harbeth video archives is a job I've just started on, long overdue but now the P3ESR's underway I'm catching up on.

As you may be aware, it seems that during these past few years I have been the only external client for the Research Dept. anechoic chamber, so much so that I leave various items behind just as I want them for the next session.