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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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13th Mar 2023, 10:39 am | #1 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
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Whatever happened to Cone Tweeters?
In my early days of building and experimenting with loudspeakers, I would always use a cone tweeter, the Wharfedale Super 3, the Elac 4" unit, Goodmans and Fane 3" units and those plastic coned EMI 2.25" ones. Time passed and soon the standard Hi Fi tweeter became the Domed type. The Japanese and USA still continued with cone tweeters for a short time, whilst they seemed to become abandoned in Europe. Was it just a case of superior technology and physics? I still sometimes hanker for the sweet sound of a coned unit. View?
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13th Mar 2023, 10:45 am | #2 |
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Re: Whatever happened to Cone Tweeters?
Domes just have a better and more linear HF response.
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13th Mar 2023, 11:11 am | #3 |
Dekatron
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Re: Whatever happened to Cone Tweeters?
And lower distortion too.
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13th Mar 2023, 11:16 am | #4 |
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Re: Whatever happened to Cone Tweeters?
And better dispersion.
"What have the dome tweeters ever done for us?", to subvert Monty Python David
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17th Mar 2023, 10:24 pm | #5 |
Hexode
Join Date: Jul 2011
Location: Hastings, East Sussex, UK.
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Re: Whatever happened to Cone Tweeters?
I have a pair of Leak Mini-Sandwich speakers that have cone speakers with a very rigid cone. They have a sandwich construction (the clue is in the title).
They sound very forward and lively to my ears but surprisingly not fatiguing. I have only listened to them on-axis and fairly near-field so cannot say about dispersion. |
17th Mar 2023, 10:54 pm | #6 |
Octode
Join Date: Nov 2011
Location: Manchester, UK.
Posts: 1,875
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Re: Whatever happened to Cone Tweeters?
3"-4" is kind of big by the time you get to the top couple of octaves (5-20kHz). Being circular, the directivity is rather unhelpfully tangled up in Bessel functions - 2J1(x)/x where x is k.a.sin(theta). k = 2.pi.f/c, c=340-ish m/s, a is piston radius (m), theta is angle off-axis.
These used to be slightly tricky to calculate, but I bet you can do it on a spreadsheet these days. I probably already shared the story where I was a bit startled to find (on debugging a Fortran77 program) that I had accidentally created a piston radius variable called 'rapist'...
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24th Mar 2023, 1:29 am | #7 |
Nonode
Join Date: Jun 2014
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Re: Whatever happened to Cone Tweeters?
I'm still fond of the sound of those old cone tweeters - especially the little plastic EMIs, And the rather splendid Wharfedale one in the SFB3 sounded good.
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24th Mar 2023, 9:16 am | #8 |
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Re: Whatever happened to Cone Tweeters?
Wharfedale had moved on from cone tweeters by the time I was running technology there. At the time there were two tweeters - identical other than the dome material. One had aluminium and the other titanium.
The selling point of titanium is that it was better than aluminium. Except it wasn't. The first break up frequency is proportional to the root of Young's modulus to density, assuming the same dome mass. Those two metals are only a percent difference in that number - 5 (ignoring troublesome powers of ten). Beryllium is much better, and was used in the legendary Yamaha NS1000M back in the late 70's onward. The figure of merit (as above) is 12.5. Wharfedale's production line would not have been able to cope with such a potentially toxic material. We were visited by a rather shady Russian guy who said he could supply "passivated" beryllium domes. We did not take him up on that. In the end, a fortuitous meeting with Idemitsu, who said they had a process for manufacturing thin sheets of 100% density alumina and would there be an application? We yes - could they make them in a dome form? Well yes they could. Figure of merit 10.2 - so getting close to beryllia - and totally non-toxic. I looked at diamond too BTW. The figure of merit is 18.6. And since it has the highest thermal conductivity of any other material (6 times greater than copper), power handling would be very high. In the late 80's manufacturing technology was just not available however, so I shelved the idea. Fast forward, and now B&W manufacture speakers with diamond dome tweeters. See for example https://youtu.be/1OUcSI2iS0Q Craig
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24th Mar 2023, 9:29 am | #9 |
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Re: Whatever happened to Cone Tweeters?
Great post Craig, thanks.
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24th Mar 2023, 9:55 pm | #10 |
Octode
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Location: Wrexham, North Wales, UK.
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Re: Whatever happened to Cone Tweeters?
These type tweeters are usually found in older vehicles, I found four in my T reg van, the treble was horrendous!
If I find old speakers fitted with whizzer type cones, I tend to leave it alone purely for historical purposes.
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