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The Lost Magnetic Property (1930-1950 Pole Piece)

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In my above post, that speaker is probably 50's - 60's, dunno

A lot of older speakers use coils as the pole magnets.

These ebay items were found with the search " vintage speakers " 2800 items  Good pics. ;] Scroll down on some, or just below the title pic, enlarge to see.



A very interesting 30's speaker by Jensen  ;]


I fell now that I have come back and re-read the whole thread
that I may have seemed a bit trite in my response to you.

I responded because I know that what you assert is true,
but the magic isn't that spectacular in retrospect really.

Before I became a marine electronics technician I had the wonder of
designing upper-frequency electrostatic tweeter assemblies by trade,
and the "other" team had to fill in the lower freq. end of the spectrum.

they did this by response-tailored core materials in the flux path

One of the things they learned early on, and you can easily test this,
is that linear motors basically suck at flat audio reproduction.

You already know this judging your comments.

But the circular flux path that the magnet contributed,
was easily damped via aluminum coated in copper.

Just like dropping a magnet down a copper tube,
the induced emf into the copper tubing during drop,
was reciprocated by a slightly less than 100% BEMF.

you will note upon testing that an aluminum tube will exert
the same effect, albeit a 12.6% difference in overall effect.

So I aside that to tell you of modern stuff that is relevant NOW !

You may very well be onto something lost to time.

Oh, and let me say this right up front,
if I answer your question as asked,
I DON'T want your money at all !

I'm retired and poor,
but that is just wrong...

Put it towards a methodological review of a core,
one that exibites the terms you exert above.

Any master maschinest worth his's/her weight in salt,
can recommend a reputable alloy spet to access this,
and grade into into a catagory and alloy number.

It (I'm near sure) will be less than your "Prize" value anyway to do this ...

But I can assure you that what your dealing with is a specific aluminum alloy,
that will be plated with an external containing barrier of another metal for sure.
(And to be clear, aluminum requires an interstificial metal to be plated with copper)

I hope this helps your awsome quest to difine the unknown.

You've got the right idea.  :)

And MaglLuvin's input is always worth It's salt for the record...

You might be interested in this?:


Other stuff

It was piece of plastic. When next to magnet it would not be attracted, but when placed in-between magnet and metal the attraction of metal and magnet stuck the plastic wiring together with and within the joined force. How to get money here?


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