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Old 2nd November 2012, 07:13 PM   #11
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Remind me to buy a crystal ball at some point.

Re different qualities or grades, it certainly does, like all magnet materials, and that's before you consider how it's formed -whether it was cast, bonded, sintered or whatever. You get different grades of each general type.

Last edited by Scottmoose; 2nd November 2012 at 07:29 PM.
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Old 2nd November 2012, 07:48 PM   #12
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Mark, you seemed surprised by the outcome of the initial results. Is it possible that there is something to the myth of Alnico?
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Old 2nd November 2012, 09:35 PM   #13
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I did some brushing up as I haven't checked in on the REE situation in a few months. The outlook is pretty good. Molycorp started mining Mountain pass CA, at the end of August and China was pressured by several countries to increase REE exports by a bit over 2%. With any luck we may see a slight dip in prices.

I'm quite curious about the potential of adding Samarium(Sm) to an AlNiCo magnet. It seems that in the presence of Cobalt it has a very high resistance to demagnetization and the second highest magnetic strength. Oh it seems that Al and Ni are left out when Co is used with Sm in a magnet. I wonder if we'll ever see these in audio transducers. Neo is more abundant and has higher magnetic potential but Samarium is very close in both those categories and it is much more thermally stable.

Does any one know if the type of magnet in a loudspeaker has an effect on self inductance of the voice coil?

-Matt

Edit- Mark(op) in your opinion is it possible that the AlNiCo could have an effect on VC self inductance and that is why you measured such a high UHF response?

Scott- You bring up a very good point. An exhaustive test of the differences in magnets for audio would have to take the manufacturing process in to account. Are you aware of a "best practice" in this regard?

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Old 2nd November 2012, 10:20 PM   #14
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Quote:
Originally Posted by Scottmoose View Post
Remind me to buy a crystal ball at some point.
and don't forget to have your unpublished ruminations carbon-dated and notarized so you can substantiate your "I tole ya so"
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Old 3rd November 2012, 12:31 AM   #15
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Quote:
Originally Posted by buzzforb View Post
Mark, you seemed surprised by the outcome of the initial results. Is it possible that there is something to the myth of Alnico?
Hi Buzz, guys
I'm not surprised by outcome due specifically to Alnico. Its worth taking another look at my posts in this thread (we're working with multiple components, of which Alnico is only 1):

is there a possibilty of seeing some MA Alpairs with alnico magnets?

Evan's proto design is unusual for this type and size of driver. His Motor Set is a "U" yoke design using a high grade steel. Theoretically, it shouldn't work as the motor hasn't nearly enough Maximum Energy Product (MEP). However, the close proximity of the magnet and the unusual design of the front washer is producing energy conversion for those driven frequencies requiring less energy within the Power Train for produce measurable and just audible emittance. Much more has to be done to investigate and analyse the properties of the design.

Even so, we should credit to Evan for having the wits to go against convention, experimenting and producing this result.

This U Yoke Motor Set alignes the internal magnet structure to within a few mm of the coil, thus restricting the driven stroke (excursion). Such designs are normally employed on tweeters and very small uber low excursion drivers using Neo magnets, as heat dissipation for low loads isn't critical. So we are a some way off from producing a more workable prototype.

Here's something for members to consider: Has Evan come up with a the "king" of cone tweeters? After-all, its passing 40-kHz, near flat and dispersion could be heavenly!

Hoping to get time over the weekend to post early results for an Alpair 6P Neo Motor Set proto design.

Cheers
Mark.

Last edited by markaudio; 3rd November 2012 at 01:17 AM.
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Old 3rd November 2012, 12:59 AM   #16
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Quote:
Originally Posted by Barleywater View Post
In "is there a possibilty of seeing some MA Alpairs with alnico magnets? #17"

And here performance is being assessed.

What are performance differences in materials? Is rare earth magnet conductive? Ferrite certainly isn't good conductor. How smoothly do magnetic fields move through each?

Barkhausen effect noise is easily demonstrated with ferrite magnets.

It looks like you are in a great position to explore this effect with Alnico materials.

Andrew
Hi Andrew,
Re you last sentence, not as such. We have plenty of data from the magnet maker to accurately assess the operational properties of individual magnet types/grades. The primary focus are the operational relationships of sets of components, as sub assemblies, when combined with other sub-assemblies, assessing the cumulative operational values. Your falling into to "single magic component trap". I don't want to lead members in a direction that could be mis-leading. Please take another look at my posts in this thread:

is there a possibilty of seeing some MA Alpairs with alnico magnets?

Thanks
Mark

Last edited by markaudio; 3rd November 2012 at 01:09 AM.
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Old 3rd November 2012, 03:22 AM   #17
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Mark, thanks for thought provoking postings of your work, very open.

Yes, I've read your postings in other thread; found 1500AL and increases my understanding of your background.


So with unexpected rising output, what was harmonic distortion and intermodulation distortion?

Regards,

Andrew
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Old 3rd November 2012, 09:54 AM   #18
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Quote:
Originally Posted by mattlong8 View Post
Scott- You bring up a very good point. An exhaustive test of the differences in magnets for audio would have to take the manufacturing process in to account. Are you aware of a "best practice" in this regard?
Not exactly. Again, it ties in with what Mark and I (albeit in my case a whole lot less authoratatively ) have been saying. You can't separate things out in that way. Not easily anyway. A magnet is just one component in the overall motor / powertrain, which is designed as a whole to produce a desired end result. To compare magnets created by different production processes, first you would need to ensure they were of the same physical proportions, same magnetic strength etc. Everything identical in other words, just one being, for e.g., cast, and another bonded. Basic scientific methodology in ensuing only one variable changes. In many cases, you'll be lucky if you manage to obtain magnets in the same grade that are identical except in terms of how they were produced.
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Old 4th November 2012, 12:29 AM   #19
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Quote:
Originally Posted by Barleywater View Post
Mark, thanks for thought provoking postings of your work, very open.
Yes, I've read your postings in other thread; found 1500AL and increases my understanding of your background.

So with unexpected rising output, what was harmonic distortion and intermodulation distortion?

Regards,

Andrew
Hi Andrew,
We're at an early stage and the Motor Set is outside T/S measurement tolerances so too soon to know. Next stage is to increase MEP and that requires several design changes to the Motor Set. With my experience, we're likely to see a lowering of the upper frequency range. Once we get the Motor Set inside tolerance, more info can be posted.
Cheers
Mark.
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Old 4th November 2012, 12:53 AM   #20
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Hello Mark,

Is there distortion performance for your drivers currently on the shelf?

Regards,

Andrew
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