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[Michael {Bink} Knowles]

I'm trying to find out who pioneered the use of ferrofluid as a cooling agent in the voice coil gap of compression drivers, which was the first application. A bunch of books and articles say that 1973 was the year, but they don't name the person or company.

[Tim McCulloch]

Binkster!  You're back!

My memory says "TAD" but I'm not certain that is correct.

1973 is a lot of brain cells ago...

[John Roberts {JR}]

Have you tried asking the manufacturer of ferro-poop...?

JR

[Mike Caldwell]

NASA invented it in the 60's.
Not sure who first had the idea to put it in a voice coil gap.

[Justice C. Bigler]

NASA invented it in the 60's.
Not sure who first had the idea to put it in a voice coil gap.

Probably some NASA engineer when he was home brewing his HiFi stereo system at home?

[Michael {Bink} Knowles]

Have you tried asking the manufacturer of ferro-poop...?

JR

Not yet. I understand Ferrofluidics in Burlington, Mass, put out a sample kit in 1973, so they're definitely on the early side.
https://www.czferro.com/ferrofluid-history

[Michael {Bink} Knowles]

... And this patent says "the 'Newsreports' section in Electrimechanical Design, October 1973 describes the use of Ferrofluids to seal the space between the poles of a loudspeaker."

https://patents.google.com/patent/US4017694A/en

[Michael {Bink} Knowles]

This Ferrotec page says "The first commercial use of ferrofluid in loudspeakers was 46 years ago, in 1973." I'll shoot them an email and ask who it was.


http://www.loudspeakerindustrysourcebook.com/united-states/bedford/liscategories/ferrotec-28usa29-corporation

[Douglas R. Allen]

I'm trying to find out who pioneered the use of ferrofluid as a cooling agent in the voice coil gap of compression drivers, which was the first application. A bunch of books and articles say that 1973 was the year, but they don't name the person or company.

I seemed to remember Radio Shack using it in their speakers back in the early/mid 1970's. I had a set of Mach 1's when they first came out and they did mention liquid cooling that I believe they said was oil but that was a few years ago.

Douglas R. Allen

[Michael {Bink} Knowles]

Ferrotec responded to my email in 36 minutes! Wow.

Marketing specialist Vanessa Rene at Ferrotec says that Bob Berkowitz of Acoustic Research began studying ferrofluid in 1972, using it to damp resonance of a tweeter. Fred Becker and Lou Melillo of Becker Electronics were also early adopters in 1976. Panasonic was the first Asian manufacturer to put ferrofluid in commercial loudspeakers, in 1979. The field grew rapidly in the early '80s, with Meyer Sound, Apogee Sound and many more jumping in.

Other archival sources show that Dana Hathaway of Epicure in Massachusetts was using ferrofluid for tweeter damping in '74, and he noticed the cooling mechanism.

By 1979, Showco was putting ferrofluid in woofers for the cooling effect.
https://books.google.com/books?id=fAEAAAAAMBAJ&pg=PA61

[Rick Earl]

I am aware of EV using it, but not sure of timeline.
https://www.electrovoice.com/binary/DH1202%20EDS.pdf

[John Roberts {JR}]

Ferrotec responded to my email in 36 minutes! Wow.

Marketing specialist Vanessa Rene at Ferrotec says that Bob Berkowitz of Acoustic Research began studying ferrofluid in 1972, using it to damp resonance of a tweeter. Fred Becker and Lou Melillo of Becker Electronics were also early adopters in 1976. Panasonic was the first Asian manufacturer to put ferrofluid in commercial loudspeakers, in 1979. The field grew rapidly in the early '80s, with Meyer Sound, Apogee Sound and many more jumping in.

Other archival sources show that Dana Hathaway of Epicure in Massachusetts was using ferrofluid for tweeter damping in '74, and he noticed the cooling mechanism.

By 1979, Showco was putting ferrofluid in woofers for the cooling effect.
https://books.google.com/books?id=fAEAAAAAMBAJ&pg=PA61

Sounds like the right people to ask... I had a pair of AR4 speaks back in day,,,,

I suspect Rat Shack may have tried to use FF as a bandaid for small drivers that released their smoke too often.

JR

[Doug Fowler]

Surprised no one has at least mentioned Community yet.

[Riley Casey]

All the Community horns I remember from the FRC, Leviathan and plastic radial horn days were strictly bring your own drivers.

Surprised no one has at least mentioned Community yet.

[Chris Hindle]

All the Community horns I remember from the FRC, Leviathan and plastic radial horn days were strictly bring your own drivers.

Ya, I had 2441's on Community BRH90 large format horns.
I think the first time I saw FF was with an EV driver. DH-1A maybe?
Chris.

[Tim McCulloch]

Surprised no one has at least mentioned Community yet.

The spec sheets online for the VHF100 and M200 are dated 1999 and make no mention of Ferrofluid... BUT... spec sheets for loudspeakers *do* mention Ferro, specifically the SLS9xx series (which use those drivers).  Anyone remember when the SLS launched?  I'm pretty sure it was after 1979...

[lindsay Dean]

Actually Radio Shack used ferrofluid in the Mach 1 series of loudspeakers.
 to my memory those things sounded pretty good for what they were

[John Roberts {JR}]

The list of who didn't use ferro fluid (ever) is probably shorter than the list of who did, but that wasn't Bink's question.

JR

[ProSoundWeb Community]