Whatever happened to Cone Tweeters? - UK Vintage Radio Repair and Restoration Discussion Forum

Edward Huggins · 13th Mar 2023, 10:39 am

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?

paulsherwin · 13th Mar 2023, 10:45 am

Domes just have a better and more linear HF response.

Craig Sawyers · 13th Mar 2023, 11:11 am

And lower distortion too.

Radio Wrangler · 13th Mar 2023, 11:16 am

And better dispersion.

"What have the dome tweeters ever done for us?", to subvert Monty Python

David

majex45 · 17th Mar 2023, 10:24 pm

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.

mark_in_manc · 17th Mar 2023, 10:54 pm

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'...

RojDW48 · 24th Mar 2023, 1:29 am

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.

Craig Sawyers · 24th Mar 2023, 9:16 am

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

stevehertz · 24th Mar 2023, 9:29 am

Great post Craig, thanks.

Glowing Bits! · 24th Mar 2023, 9:55 pm

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.

13th Mar 2023, 10:39 am	#1
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,336	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? __________________ Edward.

13th Mar 2023, 10:45 am	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,965	Re: Whatever happened to Cone Tweeters? Domes just have a better and more linear HF response.

13th Mar 2023, 11:11 am	#3
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,991	Re: Whatever happened to Cone Tweeters? And lower distortion too. __________________ Doomed for a certain term to walk the night

13th Mar 2023, 11:16 am	#4
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,899	Re: Whatever happened to Cone Tweeters? And better dispersion. "What have the dome tweeters ever done for us?", to subvert Monty Python David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

17th Mar 2023, 10:24 pm	#5
majex45 Hexode Join Date: Jul 2011 Location: Hastings, East Sussex, UK. Posts: 306	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
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,875	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'... __________________ "The best dBs, come in 3s" - Woody Brown

24th Mar 2023, 1:29 am	#7
RojDW48 Nonode Join Date: Jun 2014 Location: Bristol, UK. Posts: 2,074	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. __________________ '....don't go mistaking Paradise for that home across the road!' (Bob Dylan)

24th Mar 2023, 9:16 am	#8
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,991	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 __________________ Doomed for a certain term to walk the night

24th Mar 2023, 9:29 am	#9
stevehertz Dekatron Join Date: Sep 2011 Location: Rugeley, Staffordshire, UK. Posts: 8,833	Re: Whatever happened to Cone Tweeters? Great post Craig, thanks. __________________ A digital radio is the latest thing, but a vintage wireless is forever..

24th Mar 2023, 9:55 pm	#10
Glowing Bits! Octode Join Date: Oct 2011 Location: Wrexham, North Wales, UK. Posts: 1,457	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. __________________ Rick, the annoying object roaming the forum.