Series woofer inductor Iron Core Vs Air Core

[Jed]

Hello,

What is the audible difference for large value inductors for a woofer in series with iron core or air core if both have the same DCR? Are saturation effects audible and when do they occur?

Jed

[JonMarsh]

They occur under large signal conditions (high drive) where the current level starts to push the flux in the core near the limits of the BH curve for that core configuration. In mild cases, it increases the harmonic distortion due to the inductivity modulation with signal levels (as occurs in drivers themselves to varying degrees). In more extreme cases, a high bass transient may cause a sound almost like a cracking or thudding noise- I've heard that in some Legacy models demo'd at the factory- they use too many ferrite core inductors IMO. This was with a fairly high power amp (400W/ch)

I have designed and used large transformer style inductors in the past, using silicon steel laminations, but these days I'm pretty much 100% air core. I get the big ones from North Creek, as my own coil winder in Denver won't really handle AWG 12 wire.

~Jon

[TacoD]

I use iron core from Mundorf for large values >= 6,8 mH and up. I prefer those over ferrite core.

[morbo]

Jon what do you think of the Erse 'shaped core' inductors;

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=266-926

Does the shaped core really help offset the iron-core disadvantages?