DIY spherical ESL

[chinsettawong]

Hi Mark,

You have a very interesting project. Have you ever considered using copper clad PCBs for your stators. They are insulated, relatively flat and not very expensive to have them made. Just a thought!

Wachara C.

 

[esl 63]

Make concentric rings like on ESL 63 and physically space the circles to a sphere...

 

[blobbyts]

Its possibly worth noting that Quad had a go at making a spherical ESL in the early 90s. The prototype was hanging about the lab when I used to work there. Although it sounded pretty nice it was extremely difficult to manufacture and so the idea was dropped. I don't remember much detail around it but I recall it had stacked panels with concentric delay lines with the intent to emulate a perfect point source.
I wish I could remember more.

 

[TNT]

If it was indeed cylindrical, delay lines would not be necessary... it is already a sphere - right!? 😉

//

 

[wout31]

Its possibly worth noting that Quad had a go at making a spherical ESL in the early 90s. The prototype was hanging about the lab when I used to work there. Although it sounded pretty nice it was extremely difficult to manufacture and so the idea was dropped. I don't remember much detail around it but I recall it had stacked panels with concentric delay lines with the intent to emulate a perfect point source.
I wish I could remember more.

Any idea if any of these "balls" survived?
If so, where they are?

 

[rayma]

I recall it had stacked panels with concentric delay lines with the intent to emulate a perfect point source.

There was likely just one anyway, but it would be nice to see a photo or a sketch.

 

[wout31]

There are 2 (very vague) photo's and some info in the Quad book The closest approach by Ken Kessler on page 159-162.
There were most definitely more than one.
Stan Curtis claimed to have owned a (the) pair that survived, but that he trashed it.
Which I really don't believe, because you wouldn't trash a unique prototype set of a genius designer just like that, whatever shape it is in..
Ken Kessler claims that the drawings were lost lost in the move from Huntington to Shenzen. Which I also don't believe.
Mistery and confusion all around.

 

[MarekH]

Why dispute the claims? Quad probably had loads of prototype items which were either dismantled, tested to destruction, modified, discarded or just left on the work bench every year. My work bench and every other designers office has plenty of such items dotted all around the place. First you think "I'll fix that", then you cannibalise some parts for something else, then it goes into a box, then into the loft and finally it's tossed out. It's not in the least unusual.

My Tannoy speakers came from a builder's skip. By the time my father had come back for the Quad amplifiers which were also in there, someone else had liberated them. The Tannoys then spent (at least) another fifteen years in the loft before I built some cabinets for them. You can see them on Hans Hilberlink's site.

I still have some spare crossovers in a box in the garage...

kind regards
Marek

 

[rayma]

All research labs are like that. But you seldom have to move the entire lab, when most stuff would just get tossed.