Got neodymium?

[suntechnik]

imho light weight and hi efficiency that both come from rear earth magnets are not so critical for nice sound. Let say Magneplanars are heavy and do need some real juice from amplifiers.



Computer hard drives might be another story where small form factor and low power consumption all together makes rear earth magnets mandatory.

[Andrew Eckhardt]

I've long suspected that the raw mass of large ceramic magnet assemblies can have positive effects on sound especially in the midrange, but haven't been able to afford to proove it for myself. For high power woofers the weight savings can be a big deal. Neodymium flat out makes some tweeters possible.

[Andrew Eckhardt]

Another thing to consider is neodymium based motor assemblies routinely have shorter iron path lengths and volumes, which could possibly have as much effect on sound as the response of the magnet material itself. I've been hoping to investigate the use of underhung coils with a high grade NdFeBr material as the pole faces. I'm sure that's been done already but I'm not aware of any affordable units to shop that are built that way.

[pjp]

and neodymium is electrically conductive - which might have result in different eddy current damping of the voice coil as compared to a ferrite magnet.

[a.wayne]

Ok, this is all good, now where can i get my hands on some cheap neo's

[Variac]

And neo magnets being smaller tend to not block the rear wave of the driver. Seas has done some cool stuff with this idea..

Fostex sells very expensive brass rings to mount their drivers in the front of a baffle, to increase the mass. Nice insight that ferrite, because of its mass, might have one advantage over neo.

[Andrew Eckhardt]

nobody liked my Halbach sketch

[hunter audio]

From a geological survey of India report in early 2000 there are proven (large) deposits of all the material components that go towards making of neo mags in India

we are yet to make neo mags here on our own , and import heavily , our 4 cos making ferrite mags for speakers have closed down about 4 years back due to traders dumping cheap lower quality imports (no guess where those are coming from)

in analogy we also have large titanium deposits , we make no finished titanium yet and are buying billions of dollars worth of submarines that too only 6 of them

we have one of the worlds largest deposits of thorium , indian scientists are about months away from making their own thorium power plants when our politicians have dumped a largely controversial uranium power generation policy , all uranium being controversial imports with equally controversial disposal

calcutta is the nearest port to our mining areas , all ships coming here have legitimate cargo for india , on the way out they overstay and load illegally mined rare earth materials and proceed for processing else where

the illegal mines have been set up removing peaceful tribals , to us they may be un-educated but they live off natural materials and give to nature more than take from it , whereas the illegal mines are not conforming any environmental , forest , labor health dept regs and are felling trees and destroying at will

our most educated prime minister till date has set up our uranium hungry power plants

most of our politicians are involved in kickbacks from illegal mining

we do not develop materials here as it will stop the bureaucrats from enjoying all types of pleasure when they visit other places to secure material import tie ups

we bought long range guns , howitzer type from europe , very good ones , but banned the very own supplier on whom our army depends on .
We then ran out of shells at the heat of a battle and since our politicos had banned the gun manufacturer did not have shells for the soldiers fighting terrorists

it goes on , & it sometimes gets funny

suranjan

[Edmond Stuart]

Originally Posted by Andrew Eckhardt

nobody liked my Halbach sketch

Where? I haven't seen it yet.