I own some old speakers and I am wondering if they are demagnetized due to their age.
I searched for scientific articles but it was not possible to get any clear answer.
I suppose that the magnets are made of alnico for the 60’-70’s and neodymium for 80’s+.
So, do the permaanent magnets have a lifetime? If yes, how long is the time to get difference that is heard?
I searched for scientific articles but it was not possible to get any clear answer.
I suppose that the magnets are made of alnico for the 60’-70’s and neodymium for 80’s+.
So, do the permaanent magnets have a lifetime? If yes, how long is the time to get difference that is heard?
Alnico will age with time, mechanical shock or extremes of temperature. Neo will go away under extreme heat. Ferrite i don't know,
dave
dave
Dear Dave,
The maximum storage temperature was around 42C or 108F (summer periods).
Do you think that my old (60’s telefunken) speakers could be demagnetized?
I am talking about important difference, more than 10%.
I suppose that -1 to -2% has no impact to the final result.
Thanks
Michalis
The maximum storage temperature was around 42C or 108F (summer periods).
Do you think that my old (60’s telefunken) speakers could be demagnetized?
I am talking about important difference, more than 10%.
I suppose that -1 to -2% has no impact to the final result.
Thanks
Michalis
Alnico rates along with the best at holding it's magnetisation.
Ferrite/ceramic ranks along with the worst at holding it's magnetisation.
Ferrite/ceramic ranks along with the worst at holding it's magnetisation.
I would imagine checking the sensitivity of the speaker would be a possible test... does it meet it's SPL @1meter rating. Hardly practical to test though.
Can't say I have ever come across the issue.
And even using a large degauss wand on an old magent doesn't seem to alter it noticeably.
Can't say I have ever come across the issue.
And even using a large degauss wand on an old magent doesn't seem to alter it noticeably.
What types of magnets are there?
Alnico are easiest to demagnetize
Ceramic have low Br, which is why they need to be bigger/differently shaped.
Alnico are easiest to demagnetize
Ceramic have low Br, which is why they need to be bigger/differently shaped.
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