Q: Kapton vs Aluminum VC-former and different wire - Page 2

Joules · 21st June 2005, 07:13 PM

Any time a conductor moves through a perpendicular magnetic field, eddy currents will circulate around the field line, absorbing energy. The higher the resistivity of the conductor the smaller the circulating currents and less energy absorbed. Titanium has both stiffness and low conductivity with a small increase in mass (approx 1.6 X that of Alum). Titanium is approx 1.5 x stiffer than alum. and if done right could be made abit thinner to help compensate for it's higher dencity.

Ultima Thule · 21st June 2005, 08:54 PM

Thanks all..

Dan:

Are there any acceptable constant tempco wire with low enough resitance used for voice coils?(except that, as I mentioned earlier, someone have a patent for some alloy for VC wire, just don't find the source when looking right now, have to come back later, if my memory serves me at all..)
Do you use any kind of alloy wire for your products or just the common Copper and Aluminium?

Pajazo:

thats not the kind of source to look for, Titanium foils are very expensive, try goodfellow.com for yourself...

But if anyone knows a cheap source for Titanium foils I would really like to take part of that information!

Regards Michael

DanWiggins · 21st June 2005, 09:06 PM

Ultima,

There are two alloys that I know of, one patented by JBL and the other by Dr. Earl Geddes. Using either for voice coils would violate their patent.

We use plain copper for 99% of all drivers; aluminum only when mass must be kept to an absolute minimum (it is less conductive than aluminum, meaning for a given DCR you get less BL with aluminum as compared to copper).

Dan Wiggins
Adire Audio®

rjb · 21st June 2005, 10:07 PM

By the way, Jordan used titanium in one of his 4 inch designs, marketed by Audio and Design in 1966/67. Cost even then did not seem an issue, but it was rather difficult for him to shape. An article in November 1966 Wireless World covers this. He claims better HF and transient response using this material, but I have not seen any listener reviews. I suspect different cone shaping gave him similar results with aluminium.

Ultima Thule · 21st June 2005, 11:04 PM

Dan:

Yes, Geddes was the guy I had in mind, I did btw a search at USPTO with Geddes as inventor and came up with 153 hits, non of them talking about Low Thermal Compression Voice Coil, yet I found several other patents by the Earl G.
Would be curious to know what the patent says as Copper Nickel alloy is nothing new, but maybe the "use" of it...

RJB:

I note your point regarding the cost, good question, was Titanium so much cheaper before, however I do admit I dont know the cheapest source.
Or perhaps it was fake "Titanium", eg. heat treated Aluminium is also greyish.

Regards Michael

David Gatti · 22nd June 2005, 01:09 AM

The Scanspeak 26w8861 10" woofer, which I use in my Delta, also uses a titanium former.

Pan · 22nd June 2005, 10:06 AM

I think most of the new revelator woofers from SS uses titanium formers. Accuton also use Ti in several new drivers.

A very good Swedish speaker manufacturer (Ino Audio) also uses Ti in some designs.

/Peter

hunter audio · 22nd June 2005, 06:02 PM

hi

Ultima - I think you need the Loudspeaker Industry Sourcebook

the least - as it seems from your queries you are gearing up for production - all the best

suranjan

21st June 2005, 08:54 PM	#12
Ultima Thule diyAudio Member Join Date: Jan 2004 Location: Koskenkorva Land	Thanks all.. Dan: Are there any acceptable constant tempco wire with low enough resitance used for voice coils?(except that, as I mentioned earlier, someone have a patent for some alloy for VC wire, just don't find the source when looking right now, have to come back later, if my memory serves me at all..) Do you use any kind of alloy wire for your products or just the common Copper and Aluminium? Pajazo: thats not the kind of source to look for, Titanium foils are very expensive, try goodfellow.com for yourself... But if anyone knows a cheap source for Titanium foils I would really like to take part of that information! Regards Michael __________________ "If transistors are blueberries and FETs are strawberries, then tubes must be.. pears" Michael 29th January 2010

21st June 2005, 10:07 PM	#14
rjb diyAudio Member Join Date: Jun 2004 Location: Piha	Titanium By the way, Jordan used titanium in one of his 4 inch designs, marketed by Audio and Design in 1966/67. Cost even then did not seem an issue, but it was rather difficult for him to shape. An article in November 1966 Wireless World covers this. He claims better HF and transient response using this material, but I have not seen any listener reviews. I suspect different cone shaping gave him similar results with aluminium.

21st June 2005, 11:04 PM	#15
Ultima Thule diyAudio Member Join Date: Jan 2004 Location: Koskenkorva Land	Dan: Yes, Geddes was the guy I had in mind, I did btw a search at USPTO with Geddes as inventor and came up with 153 hits, non of them talking about Low Thermal Compression Voice Coil, yet I found several other patents by the Earl G. Would be curious to know what the patent says as Copper Nickel alloy is nothing new, but maybe the "use" of it... RJB: I note your point regarding the cost, good question, was Titanium so much cheaper before, however I do admit I dont know the cheapest source. Or perhaps it was fake "Titanium", eg. heat treated Aluminium is also greyish. Regards Michael __________________ "If transistors are blueberries and FETs are strawberries, then tubes must be.. pears" Michael 29th January 2010

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21st June 2005, 07:13 PM	#11
Joules diyAudio Member Join Date: Nov 2004 Location: Manassas virginia usa	Any time a conductor moves through a perpendicular magnetic field, eddy currents will circulate around the field line, absorbing energy. The higher the resistivity of the conductor the smaller the circulating currents and less energy absorbed. Titanium has both stiffness and low conductivity with a small increase in mass (approx 1.6 X that of Alum). Titanium is approx 1.5 x stiffer than alum. and if done right could be made abit thinner to help compensate for it's higher dencity.

21st June 2005, 09:06 PM	#13
DanWiggins diyAudio Member Join Date: Aug 2002 Location: Seattle or Shanghai	Ultima, There are two alloys that I know of, one patented by JBL and the other by Dr. Earl Geddes. Using either for voice coils would violate their patent. We use plain copper for 99% of all drivers; aluminum only when mass must be kept to an absolute minimum (it is less conductive than aluminum, meaning for a given DCR you get less BL with aluminum as compared to copper). Dan Wiggins Adire Audio®

22nd June 2005, 01:09 AM	#16
David Gatti diyAudio Member Join Date: Mar 2004 Location: Melbourne, Australia	The Scanspeak 26w8861 10" woofer, which I use in my Delta, also uses a titanium former.

22nd June 2005, 10:06 AM	#17
Pan diyAudio Member Join Date: Sep 2002	I think most of the new revelator woofers from SS uses titanium formers. Accuton also use Ti in several new drivers. A very good Swedish speaker manufacturer (Ino Audio) also uses Ti in some designs. /Peter

22nd June 2005, 06:02 PM	#18
hunter audio diyAudio Member Join Date: Dec 2003 Location: calcutta	hi Ultima - I think you need the Loudspeaker Industry Sourcebook the least - as it seems from your queries you are gearing up for production - all the best suranjan

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