The Audiophoolery Thread.

The speakers are drop dead gorgeous

Arghhh! I wouldn't give them room in my outside bog (if I had one). For that sort of money (if I had it spare) I would buy a field in the middle of nowhere and plant an antenna farm, caravan in the middle.

[Radio Wrangler]

I definitely agree with MM. Those things look like dog's breakfasts where somebody threw everything they thought might look impressive at them.

I always smile when I see speakers so fashionably narrow that their dainty little feet need to be cantilevered outwards on tiny outriggers to stop the speakers falling over.

There cn be advantages in small amounts of cabinetry around radiators, but it's wavelength scaled, so small tweeters in pods make sense, but bass drivers need volume behind them.

If they're going to take up a particular amount of floorspace, then they ought to exploit it all.

David

[The Philpott]

'In-store stock available for audiophile emergencies'.
I wonder what an example of an audiophile emergency might be. I was never really aware of this odd parallel universe before i came here..and now i can't bring myself to feel guilty for mocking it's inhabitants.
Dave

[mark_in_manc]

Originally Posted by The Philpott

'In-store stock available for audiophile emergencies'.
I wonder what an example of an audiophile emergency might be.

The genre seems to have something in common with addiction - returning for another 'hit' of something which ultimately fails to satisfy, thus making it necessary to return for...etc etc.

If this is the case, the shop seems to regard itself as something like a methadone clinic

[Radio Wrangler]

Audiophilia seen as an addiction.... hmmm... yes, that fits.

I'd been seeing it as a religion because it fits that too. Division of the world into believers and non-believers, belief as an act of faith without any possibility of objective proof.

What was that phrase? 'The opiate of the..." Um, yes, let's not go further down that path, it'll only get people upset.

But they're missing out by not registering as a religion... they could bypass planning permission (like churches do) AND claim VAT back... and at their prices, that is a considerable consideration indeed!

David

[Craig Sawyers]

Regarding the speakers that are dividing opinion, the use of diamond tweeters is an interesting one (apart from why so many?).

Before I joined Wharfedale, I did quite a lot of consultancy work for them (I worked for Scientific Generics). The main part of that was new materials for tweeters. The main attribute, to increase the first resonant peak frequency, is the Young's modulus to density ratio. Using this, you can rank materials. I also pioneered the use of FE analysis in looking at the behaviour of tweeters. We worked out the the optimum section was not spherical, but elliptical with a particular form.

Now at that time, Wharfedale were using aluminium and titanium domes. Titanium was touted as the material used in there higher priced speakers. But the YM/dense ratio was almost identical, and given similar thickness material, the first resonance was at precisely the same frequency. And very close to the audio band, and rather high Q.

Anyway, it was absolutely clear that diamond was by far the best material; but in the late 80's it was not economically feasible. Next were ceramics like silicon carbide - but fabrication was still an issue.

I then visited a start up company in Germany, working out of a defunct cinema, who were making drive unit diaphragms out of alumina. They formed thin aluminium sheet into the desired shape, and then anodized it all the way through. Then they fired the green alumina in a furnace. That certainly worked. But the density was rather low (because anodizing produces a porous material), and it was not clear that the two-man outfit would survive as a company (it didn't).

Then a strange Russian appeared touting Beryllium domes, and brought some samples. Now Be is *almost* as good as diamond, and streets ahead of other materials we'd been looking at. It was pioneered in the 70's by Yamaha in the iconic NS1000M. But toxicity on the (Wharfedale) dark satanic mills shop floor, and continuation of supply from what was still the USSR was a concern.

At about that time, we (Generics) were visited by Idemitsu Petrochemical. They mentioned that they had developed a CVD technology for making thin alumina sheet, and could we think of an application? Er- yes....

And that ended up being the supplier of thousands of ultimate density alumina domes to Wharfedale.

But the glint in the eye was always diamond. A commercial speaker that uses a diamond tweeter was, and still is, made by B&W. And now the outfit that I gave the link to a few posts back.

But the beaming in high frequencies caused by having so many tweeters (diamond or not) clustered together with a high net radiating area is a major downside in that design.

Craig

[Radio Wrangler]

There is always the opt-out of going electrostatic or magnetic structures equivalent to the old isodynamic headphones (had a pair of those and liked them a lot)

There is a mismatch between a voice coil, which produces force from a ring-shaped cross section, and the need to move air, which needs force across a reasonable cross-section area.

Maybe the Quad ESL63 with its shaped and delayed fields was an idea worth scaling down for the archetypal nearly perfect tweeter?

Phased array antennae are used to form narrow beams for radar (and they keep talking about MIMO) but the opposite trick of forming an omni pattern would be just as feasible. Well, an omni pattern synthesised to cover a limited spread angle.

David

[Craig Sawyers]

The planar electromagnetic structure of the old isodynamic headphones is alive and well in full-size loudspeakers

http://www.magnepan.com/models

Indeed conventional loudspeaker drivers are full of compromises, with Klippel being the key person/company who produce software that most loudspeaker drive unit manufacturers use to pilot through the intricacies. http://www.klippel.de/ and his technical papers here http://www.klippel.de/know-how/literature/papers.html , most of which are heavy hitting treatments of the topics.

The main thing in conventional driver's favour is their ability to move air and play loud. By comparison full-range electrostatic loudspeakers, with much lower distortion, are limited in volume mainly by low frequency excursion. Some manufacturers have integrated electrostatic mid/tweeter with a conventional bass driver to overcome that limitation https://www.martinlogan.com/en/

And let's not forget that electromagnetic driven cone loudspeakers for sound reproduction date back to Rice and Kellog (no kidding) in 1925 at General Electric. And Kellog went on to invent the electrostatic loudspeaker in 1934. And were the subject of patents at that time.

So really there is nothing really new in all this. Only materials technology and computer analysis have happened in the intervening nearly-a-century.

The Quad ESL63 (so called because Peter Walker invented it in 1963) is one of very few innovations since then. All Quad ESL's since then have used this principle.

Craig

[Radio Wrangler]

The first combined cone/piston with electrostatic mid/tweeter setup I ever heard was the B&W DM70 but badged as the Sony SS7000. Early 70's.

Advanced materials and the ability to analyse things in progressively finer finite-element style will take you so far, maybe far enough, but I can't help feeling that point source and line-source forces are intrinsically mis-matched to the goal of achieving distributed force over a finite area. I think there is room for something different to be discovered or developed.

David

[Craig Sawyers]

OK - the spherical wavefront ESL that is attributed to Quad is in Kellog's 1934 patent!

Attached.

Craig

[Craig Sawyers]

Relevant patent extract attached

Craig

[stevehertz]

Originally Posted by Craig Sawyers

Regarding the speakers that are dividing opinion, the use of diamond tweeters is an interesting one (apart from why so many?).

Before I joined Wharfedale, I did quite a lot of consultancy work for them (I worked for Scientific Generics). The main part of that was new materials for tweeters. The main attribute, to increase the first resonant peak frequency, is the Young's modulus to density ratio. Using this, you can rank materials. I also pioneered the use of FE analysis in looking at the behaviour of tweeters. We worked out the the optimum section was not spherical, but elliptical with a particular form.

Now at that time, Wharfedale were using aluminium and titanium domes. Titanium was touted as the material used in there higher priced speakers. But the YM/dense ratio was almost identical, and given similar thickness material, the first resonance was at precisely the same frequency. And very close to the audio band, and rather high Q.

Anyway, it was absolutely clear that diamond was by far the best material; but in the late 80's it was not economically feasible. Next were ceramics like silicon carbide - but fabrication was still an issue.

I then visited a start up company in Germany, working out of a defunct cinema, who were making drive unit diaphragms out of alumina. They formed thin aluminium sheet into the desired shape, and then anodized it all the way through. Then they fired the green alumina in a furnace. That certainly worked. But the density was rather low (because anodizing produces a porous material), and it was not clear that the two-man outfit would survive as a company (it didn't).

Then a strange Russian appeared touting Beryllium domes, and brought some samples. Now Be is *almost* as good as diamond, and streets ahead of other materials we'd been looking at. It was pioneered in the 70's by Yamaha in the iconic NS1000M. But toxicity on the (Wharfedale) dark satanic mills shop floor, and continuation of supply from what was still the USSR was a concern.

At about that time, we (Generics) were visited by Idemitsu Petrochemical. They mentioned that they had developed a CVD technology for making thin alumina sheet, and could we think of an application? Er- yes....

And that ended up being the supplier of thousands of ultimate density alumina domes to Wharfedale.

But the glint in the eye was always diamond. A commercial speaker that uses a diamond tweeter was, and still is, made by B&W. And now the outfit that I gave the link to a few posts back.

But the beaming in high frequencies caused by having so many tweeters (diamond or not) clustered together with a high net radiating area is a major downside in that design.

Craig

Really fascinating Craig, thanks. Out of interest, what speakers do you use at home?

[Craig Sawyers]

These https://www.linkwitzlab.com/LX521/LX521_4.htm made by my own fair hand, analogue processor (ie electronic crossover) and ten channels of power amp.

Craig

[Craig Sawyers]

And this is what mine look like

[M0AFJ, Tim]

Originally Posted by Craig Sawyers

The speakers are drop dead gorgeous (and a normal house mortgage price). Add an array of subwoofers and you talking a million quid.

But look at the cable prices further down the page

https://audiofederation.com/brands/k...rma-price-list
https://kharma.com/

Craig

Hells teeth....

[stevehertz]

Originally Posted by Craig Sawyers

These https://www.linkwitzlab.com/LX521/LX521_4.htm made by my own fair hand, analogue processor (ie electronic crossover) and ten channels of power amp.

Craig

Intriguing!

And this is what mine look like

And there was I thinking that my Tannoy DC4s were the dogs whatsits for my needs, spoken word radio plays and drama. They do a splendid job with pinpoint stereo "imaging" which is a very good thing for a radio play. Must be down to the (Chinese made, well done too) dual concentric drivers.

[Herald1360]

Originally Posted by Craig Sawyers

And this is what mine look like

Sound pressure barometer comes to mind

Quite beautiful in their own way.

[GrimJosef]

Originally Posted by stevehertz

Intriguing!

And they sound lovely too (I've been lucky enough to hear them ). They're dipole radiators so placement matters, of course. They can't be placed backs-to-the-wall, for example.

I've said before that IMHO many people who spend a small fortune on speakers (of any kind) then spend too little time positioning them optimally. It can make a big difference.

Cheers,

GJ

[Beobloke]

I've been attending the Munich High End Hi-Fi Show for the past ten years and the Kharma room is consistently one of the best sounding to my ears. Fantastic loudspeakers and they always have nice comfy chairs that are superb to take a break in from pounding the halls! They also fully decorate their rooms with rugs, leather wallcoverings, pictures etc and the build quality of both this and the products themselves is nothing short of astounding.

Frankly, when my lottery numbers come up, I could be sorely tempted by a Kharma A/V room - https://kharma.com/projects/av-projects/

In fact, the only downside of them at Munich is they do have a tendency to play appalling music. Whilst the music at Munich is generally focused on dreary audiophile GWG interspersed with what sounds like pianos being pushed down a flight of stairs, Kharma do seem to be one of the worst offenders, which is a great shame.