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Old 26th April 2008, 12:22 AM   #1
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Default oil in speaker coil section

hi, is ther any one knows about puting oil into loud speaker coil section? i just want to know why should put oil in there?

thank you.
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Old 26th April 2008, 12:29 AM   #2
badman is offline badman  United States
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It's like oil, it's something called 'ferrofluid'. It's a magnetic liquid, useful in improving conduction of heat from the voicecoil to the magnet structure. This gives greater power handling. It also contributes to influencing the low end response of the driver (usually a tweeter).

Whether it's desirable or not depends upon a variety of factors. Don't just try adding it, you may ruin the response of the driver near Fs, or overdamp it throughout its operating range
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Old 15th November 2014, 01:02 PM   #3
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Quote:
Originally Posted by badman View Post
It's like oil, it's something called 'ferrofluid'. It's a magnetic liquid, useful in improving conduction of heat from the voicecoil to the magnet structure. This gives greater power handling. It also contributes to influencing the low end response of the driver (usually a tweeter).
Whether it's desirable or not depends upon a variety of factors. Don't just try adding it, you may ruin the response of the driver near Fs, or overdamp it throughout its operating range
Hello to Everyone !
i get back to this old thread because i had to dismantle two Dynaudio tweeters to reshapen the domes that were crushed (just pushed dwon but they seem ok. i hope --- )

Click the image to open in full size.

In the operation some ferrofluid has been moved to my fingers
What should i do ? to add or not to add some ?
Advice will be very welcome
Thanks and regards, gino
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Old 15th November 2014, 01:24 PM   #4
jmsent is offline jmsent  United States
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Did you get ferrofluid on your fingers by taking the tweeter apart? I ask, because hopefully, there's no fluid on the dome surface itself, because that's the kiss of death for a textile dome tweeter. A tiny bit of ferrofluid on your fingers is not going to make any difference in performance. And since you probably have no idea of the viscosity of that fluid, you would not know what to put in there anyway. You should always remove a voice coil very slowly from the gap when ferrofluid is present.
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Old 15th November 2014, 01:44 PM   #5
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Originally Posted by jmsent View Post
Did you get ferrofluid on your fingers by taking the tweeter apart? I ask, because hopefully, there's no fluid on the dome surface itself, because that's the kiss of death for a textile dome tweeter.
Hi and thanks for the precious reply.
I think so and sure i did not know of the oil inside and above all about its nasty effect on the dome
You know what ... never a textile dome again. Just nice and shiny aluminum
It seems that life must be necessarily compicated.
And the nice thing is that tweeters should have been the strong point

Quote:
A tiny bit of ferrofluid on your fingers is not going to make any difference in performance. And since you probably have no idea of the viscosity of that fluid, you would not know what to put in there anyway.
Of course ... i have completely no idea of the kind of liquid
It seems like car oil after some kms ... i was even thinking to use synthetic oil for car engines ... maybe it works ?
But also the needed quantity is a mistery

Quote:
You should always remove a voice coil very slowly from the gap when ferrofluid is present
You are right i did not know about the oil presence.
Good thing is that now the dome look decent and the coil support does not look damaged
I will put them together again and listen.
I receive the speakers by mail. Next time i will act differently.
I see a model number on the magnet ... 81702
You know what ... now that i look better the tweeters are not the same of the picture above found on internet
Maybe the chinese effect is already working
Next time i will be more careful in the purchase
There is no comparison with the tweeter above ...
Thanks a lot again
Kindest regards, gino
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Old 15th November 2014, 02:18 PM   #6
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Hi ! i have riassembled the tweeters and they seem to work
I have found a nice sweep generator on the web

LF Generator

no grasping sounds on the tweeter up to 17000 Hz
I am sure their balance has changed ... i would be more careful next time for sure
I will never open them again
Thanks a lot again for the precious advice
Kindest regards, gino

Last edited by ginetto61; 15th November 2014 at 02:29 PM.
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Old 15th November 2014, 04:12 PM   #7
JMFahey is offline JMFahey  Argentina
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Quote:
i was even thinking to use synthetic oil for car engines ... maybe it works ?
Please NO .

The keyword in ferrofluid is ferro, it is magnetic and magnetic field keeps it where it belongs: the gap.

Standard Oil (no, I'm not referring to the monster Oil company ) will go anywhere and mess everything, including the textile dome.

Your tweeter will feel like this poor penguin:

Click the image to open in full size.
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Old 15th November 2014, 04:49 PM   #8
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Originally Posted by JMFahey View Post
Please NO .
The keyword in ferrofluid is ferro, it is magnetic and magnetic field keeps it where it belongs: the gap.
Standard Oil (no, I'm not referring to the monster Oil company ) will go anywhere and mess everything, including the textile dome.
Your tweeter will feel like this poor penguin:
Click the image to open in full size.
Hi and thanks for the valuable advice
Really a sad picture you have posted
It is part of the price the nature pays to the progress
Going back to the fluid i understand now is not only oil but a mix with some ferric compound i do not know ...
I am not going to open them again because i could damage the coil and its support
I have made a sweep without noticing scratching sounds
This is indeed a lesson for me
These tweeters are indeed delicate parts
And i cannot understand the vice to crash the domes i see in the supermarkets ... this is very silly habit and speaks a lot for the people doing this
Actually i would like to see also more woofer shaped like an inverted dome
I love this kind of woofer ... there is an idea of perfection in the spherical objects

Click the image to open in full size.

thanks a lot again
Kindest regards, gino
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Old 15th November 2014, 05:06 PM   #9
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Perhaps contacting these guys for advice. There are many types of ferrofluid, with varios viscosities and particle sizes that have great impact on results. Better to replace with similar than not IMO.
Simply Speakers Ferrofluid Replacement Kits
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Old 15th November 2014, 05:12 PM   #10
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JMFahey, I do wildlife rescue, in particular costal/seabirds. Can deal with the oily birds, Dawn detergent works wonders, but not the loss of habitat and the long term never ending cleanup.
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