Pssst, Scott; Babb's patent permanently expired today

[Scottmoose]

It was indeed. Since it was there as a support / guide the OA frictional losses were probably quite minor (I can't say I've tried to test it) & the Lorelei certainly was broadband -albeit not the most efficient driver under the sun. 😉

 

[TNT]

I've been reading the patent, fascinating. Teflon bearing to support the voice coil? Would that really be slippery enough for a broadband driver?

Stiction comes to mind...

//

 

[Pano]

For sure. From the patent illustration the Teflon bearing is narrow and only at one point. But it still seems hard to believe it works well. Or that is wears well.
The split voice coil is an interesting idea.

 

[Pano]

albeit not the most efficient driver under the sun.

Would that be because of the small cone diameter? The patent talks about the motor being efficient.

 

[Scottmoose]

Bit of both IIRC -small size for the BW, & long-throw split coil / dual gap motors aren't generally the most efficient of configurations (accepting these things are relative).

 

[jjasniew]

Hard to believe anything that's solid and touches as a bearing in part of a VC motor assembly would not be heard.

 

[Scottmoose]

I suppose it depends what you mean by 'heard'.