Optimal multilayer coil for the audio filters is a Brooks coil

[cyberstudio]

https://coil32.net/crossover.html

I don't get it. If this was invented in 1931 why isn't everybody doing this when winding air-core inductors? The shortest wire to do the job always gives the lowest DCR and the lowest cost. And some math must necessarily exist to compute that optimal shortest wire (Brooks). But it seems like everyone is pursuing exotic materials like litz wire and silver instead of following the basics?

 

[AllenB]

While the use of Litz wire is a question on it's own, it's use doesn't conflict with the above information. I see this winding scheme used often.

 

[lcsaszar]

I think this geometry was found optimal also by A. N. Thiele in Air-Cored Inductors for Audio (JAES June 1976).

 

[Mark Tillotson]

Has someone looked at tape-wound inductors for comparison? I'm guessing the geometry would be the same, but better winding density, although different stray capacitance...