ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB: The Classic Live Audio Board => Topic started by: Michael {Bink} Knowles on August 31, 2019, 02:02:52 pm

Title: Who was using ferrofluid in 1973?
Post by: Michael {Bink} Knowles on August 31, 2019, 02:02:52 pm
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.

Title: Re: Who was using ferrofluid in 1973?
Post by: Tim McCulloch on August 31, 2019, 03:22:42 pm
Binkster!  You're back!

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

1973 is a lot of brain cells ago...
Title: Re: Who was using ferrofluid in 1973?
Post by: John Roberts {JR} on August 31, 2019, 05:25:00 pm
Have you tried asking the manufacturer of ferro-poop...?

JR
Title: Re: Who was using ferrofluid in 1973?
Post by: Mike Caldwell on September 01, 2019, 07:24:34 am
NASA invented it in the 60's.
Not sure who first had the idea to put it in a voice coil gap.
Title: Re: Who was using ferrofluid in 1973?
Post by: Justice C. Bigler on September 01, 2019, 01:18:07 pm
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?
Title: Re: Who was using ferrofluid in 1973?
Post by: Michael {Bink} Knowles on September 01, 2019, 03:31:13 pm
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
Title: Re: Who was using ferrofluid in 1973?
Post by: Michael {Bink} Knowles on September 01, 2019, 03:34:22 pm
... 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
Title: Re: Who was using ferrofluid in 1973?
Post by: Michael {Bink} Knowles on September 03, 2019, 01:20:55 pm
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
Title: Re: Who was using ferrofluid in 1973?
Post by: Douglas R. Allen on September 03, 2019, 02:35:33 pm
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
Title: Re: Who was using ferrofluid in 1973?
Post by: Michael {Bink} Knowles on September 03, 2019, 03:03:12 pm
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
Title: Re: Who was using ferrofluid in 1973?
Post by: Rick Earl on September 03, 2019, 03:13:21 pm
I am aware of EV using it, but not sure of timeline.
https://www.electrovoice.com/binary/DH1202%20EDS.pdf (https://www.electrovoice.com/binary/DH1202%20EDS.pdf)
Title: Re: Who was using ferrofluid in 1973?
Post by: John Roberts {JR} on September 03, 2019, 04:31:56 pm
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
Title: Re: Who was using ferrofluid in 1973?
Post by: Doug Fowler on September 03, 2019, 09:29:06 pm
Surprised no one has at least mentioned Community yet.
Title: Re: Who was using ferrofluid in 1973?
Post by: Riley Casey on September 03, 2019, 09:39:01 pm
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.
Title: Re: Who was using ferrofluid in 1973?
Post by: Chris Hindle on September 04, 2019, 12:03:53 am
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.
Title: Re: Who was using ferrofluid in 1973?
Post by: Tim McCulloch on September 04, 2019, 12:15:21 am
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...
Title: Re: Who was using ferrofluid in 1973?
Post by: lindsay Dean on September 04, 2019, 01:32:21 pm
Actually Radio Shack used ferrofluid in the Mach 1 series of loudspeakers.
 to my memory those things sounded pretty good for what they were
Title: Re: Who was using ferrofluid in 1973?
Post by: John Roberts {JR} on September 04, 2019, 02:45:19 pm
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