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New to Harbeth and very happy! (And more on Harbeth's unique RADIAL cones)

Stephen_S

New member
Hi Everyone,
I'm new to this forum and to owning Harbeths, though I've known of them for years. My first direct experience with Harbeths was at RMAF in 2013, where I heard 30.1s along with a Bricasti M1 DAC and was very, very impressed with what I had heard.

I had read about Harbeths for years in the various publications for years prior, but never really "understood" what all the fuss was until I went into that room at RMAF. That first experience stayed with me, and in the beginning of 2014, I spent an entire evening audition 30.1s at Tone of Music in San Francisco with my the brand of electronics I use, Conrad-Johnson.

The dealer used an ET-3 preamp and LP66S power amp, and that simple system was one of the best systems I had ever heard, regardless of price. The reason was it because it had created such an engaging and beguiling musical experience. That singular evening has stayed with me for over 5 years, and I'm now proud to say that yesterday, I took delivery of a beautiful pair of Harbeth 30.2s.

These are being driven by my Schiit Gungnir Multibit DAC, Michell Gyro SE/SME V/Koetsu Urushi Vermilion, Conrad-Johnson CT-5 preamp and LP-70S power amp and full Shunyata cables, power cords, and power distribution.

Very happy to be here! As soon as my new stands arrive, I'll post some photos of the system.
 

A.S.

Harbeth UK
Staff member
Welcome! Nothing pleases me more than hearing of a lasting memory from exposure to Harbeth.

I too have such a recollection from the 1980s of my mistaken conversion of the bextrene coned BC1 to the polypropylene coned SP1, and my shock at the (then inexplicable to me) change in sound quality. Days later, meeting Dudley Harwood and him loaning me his new Mk4 with advanced cone technology, and after a brief listen the fate of my adult life was set. And I knew it.

That moment from 32 years ago. How I felt in response to the new open sound is still recollectable. It was as if a thin blanket had been lifted off the polypropylene coned speakers.
 

Miles MG

New member
Re. the Bextrene coned BC1 & the polypropylene coned SP1, I well recall the ‘hoo-ha’ when the Spendor SP1 was released. Luminaries such as the reviewer Martin Colloms were very enthusiastic about it. As a long-term BC1 owner I read all the reviews with interest, but never got to hear the SP1s.

In this new Century polypropylene is meant to be a ‘no-no’ as far as loudspeakers are concerned. Not for all manufacturers, as Graham Audio has made a new version of the LS5/9 which has been well received. For myself, I will never sell my Spendor BC1s...
 

A.S.

Harbeth UK
Staff member
I have a brand new pair of modern reinterpretations of the LS5/9 which I was sent by a customer who changed his mind before taking delivery. One sealed carton I opened, the other remains sealed. I measured them in the lab. I am convinced that the tweeter crossover is either misdesigned or that the tweeter is incorrectly wired out of phase. To progress to a conclusion, I would have to open the other sealed carton.

The other striking recollection is that the high frequency extension is pitiful - the wide diaphragm tweeter output drops off like a stone robbing music of the sparkle of naturalness. And then there is the polypropylene fogging of sound. What a miserable and futile exercise. Rather reminds me of the Austin A40 I passed struggling along the motorway near Stratford-upon-Avon today. “Why put yourself through that?”

By the way: visitors to our rooms at the Bristol show in February last may have seen my occasional presentation. I brought along a laptop, measuring software and a precision microphone which I moved in front of the speaker as it played test signals. No media coverage (unsurprisingly) that an audio brand dared to prove the performance of its speakers objectively and very publicly (an unwelcome precedent perhaps) but it made my point. I demonstrated that there is one, and only one, vertical point perpendicular to the baffle and between floor and ceiling, where the sound waves from the drive units must converge perfectly despite the tweeter being physically closer to the mic than the woofer (a critical function of a well designed, multi component crossover. I couldn’t find that point with the modern 5/9 I I measured which can only mean a design or assembly fault.

I should also add that the LS5/9 historically manufactured by BBC licensees (Rogers, some Spendor ones) of which we have both in the lab, are characteristically similar but completely different to the frequency response of the public BBC Design Report which describes a prototype, not production specimen. Making the prototype report public presumably gave some commercial advantage to the then licensees who were marketing the final BBC approved version. For whatever reason at the time, the BBC’’s golden ears, presumably after field testing in real BBC studios with their experienced sound engineers, dramatically reworked the design post-prototype to give them the sound that they had confidence in. This was how the 3/5, 3/5A, 5/8 and in my personal experience the 5/12, 5/12A came to market - all design passed from prototype to production phases, adjusted as needed. From what I measure of this modern reinterpretation, it looks like it has taken the BBC prototype report as its design remit. That means that to have the original 1980s 5/9 sound as actually mass produced and sold into BBC studios, it would be necessary to actually buy a pair of those original models second hand, perhaps ex-BBC, hence the high prices commanded for the 1980s originals.
 

A.S.

Harbeth UK
Staff member
I understand from a private message today that there is evidence that the speaker I examined measures as it does because it’s Design Reference Axis is not on or about a line drawn perpendicular to the tweeter but perpendicular to the centre of the bass unit.

If that is so, then it did not occur to me to disassemble and disturb my reference measurement setup which is good enough for all Harbeth and other normal speakers to find this very unusual sweet spot. I would anticipate most serious listeners to be seated on a chair and with their ear ideally level with the Reference Axis when listening not sitting on the floor. It could be, intentionally, that the speaker cabinets are designed to be turned upside down in use as implied by such a low Reference Axis. If so, that is a further reinterpretation as it is not part of the Prototype report and not how the original was actually used in-studio.
 

MikeT.

New member
Harbeth had lingered in my memory for several years after hearing a pair at a store in Texas and then again at a expo in Chicago. When I finally purchased my C7ES3’s, I immediately noticed I could understand lyrics which had previously escaped me. When I began reading Alan Shaw’s comments regarding design philosophy and the human voice I had an “ah moment” of understanding.

Another important change. More listening, without simultaneous iPad internet surfing. Extremely pleased!
 

ahofer

Member
"It was as if a thin blanket had been lifted off the polypropylene coned speakers."

As you know, this isn't a quantifiable description. To what measurement would you attribute it?

I had the same feeling after listening to a variety of other speakers then listening to the SHL5+. I find it odd how many people still characterize Harbeths as having a "warm voicing" and thus lacking transparency. It was the opposite to me. Or rather, there was "warmth" that came from *more* detail, rather than the implied rolled-off sound of the stereotype. Distinctly different from the tubey warmth I'd been told to admire.
 

A.S.

Harbeth UK
Staff member
I have compressed the 2000+ A4 pages of the Harbeth RADIAL into one phrase 'foggy polypropylene' as a listening experience. There are wholly factual characteristics of the chemistry of polypropylene sheet which make it an obvious short list candidate as a speaker cone material (low mass and cost) but at a price in absolute acoustic quality. As always, a trade off.

We've discussed this at length here: see my video on the buckling failure of polypropylene under load.

It is simply a matter of going to the dealer and listening.
 

ahofer

Member
Yes, I have seen that video. It's very convincing about drivers holding their shape under pressure. I guess what I'm asking is, if we put a microphone in front of the speaker, what would we see in the frequency and amplitude of the signal that corresponds to cone shape warping (or the 'fogginess'). Maybe I'm missing something obvious.

I listened to a lot of fancy speakers with, among other things, exotic metals and even diamond-impregnated driver materials. Typically, with the more exotic materials, I seemed to hear harsher, dryer sounds (again with the unquantifiable impressions). Yet I expect they are also light and hold their shape well.

I hope you understand I'm not trying to be too clever (in the less-flattering British sense) with you. You have often criticized other people's subjective descriptions as being unquantifiable or unmeasurable (more re. amplifiers and cables). Certainly "fogginess" and "coloration" are in that category I'm wondering how we get to objectivity here. Are you able to tie the Harbeth sound to a more accurate measurement that could be compared with other speakers? I would think you had, or had tried.
 

A.S.

Harbeth UK
Staff member
ahofer said:
... I hope you understand I'm not trying to be too clever (in the less-flattering British sense) with you. You have often criticized other people's subjective descriptions as being unquantifiable or unmeasurable (more re. amplifiers and cables). Certainly "fogginess" and "coloration" are in that category I'm wondering how we get to objectivity here. Are you able to tie the Harbeth sound to a more accurate measurement that could be compared with other speakers? I would think you had, or had tried.
It would be asburd if we were to make a claim such as 'polypropylene sounds foggy' and were not able to back it up. Actually this has been thoroughly discussed here before, and I take you back to 1990 when we were in receipt of a grant from the Science and Engineering Research Company to fund three graduate engineers to convert my comment 'polypropylene sounds foggy' into a proper objective understanding of how sound waves behave in polymers.

And the conculsion was that there is no off the shelf material that has a better blend of properties, and many far worse. But the achilies heal of PP is so extremely obvious (with hindsight) to any 3rd year chemical student pondering the use of any polymeric material as a speaker cone that it's quite shocking that we have kept this discovery to ourselves for a quarter century. It both is, and isn't rocket science.

When one receives government funding (from the taxpayer), you have a quarterly presentation to the men from the ministry concerning progress in the presence of academics who are experts in the area of study. The master report that we wrote-up as we proceeded runs to 2333 pages (PDF 233MB).

To give you a sense of the scale of the challenge of out-performing polypropylene, you have to completely understand its weaknesses. Viewed as thumbnails below, that is what the RADIAL project report looks like, some five man years of blue-sky research, and you would need to understand it all to be in a position to make our RADIAL material. Quite a challenge in an industry where romance is a far more effective sales tool than objectivity.


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ahofer

Member
Unfortunately, I can't seem to load these pictures, clicking just produces a blank screen. Don't know if that is me.

"Quite a challenge in an industry where romance is a far more effective sales tool than objectivity."

Indeed. But I've noticed even the hardcore subjectivists will hop on measurements when they are available (even, or perhaps even more, inaudible measurements, such as 0.005% THD and 100 db vs 113 db SINAD). I think a simple one speaker vs another, side by side, here are the artifacts in the sound created by floppy/rigid/others' drivers, would be effective, as opposed to "here are the problems with Polypropylene". Is that what the picture shows? Have you shown it elsewhere (sorry, I'm relatively new to this forum and I apologize if this is old ground).

As I say, I'm convinced I hear it subjectively. Would love to know what is objectively there, seeing as my brain/eyes/expectations are always interfering.
 
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