Blog: Upgrade Inductors with Care

Since the topic of upgrading crossovers comes up a lot I wrote a post that I hope you'll find useful.


@erik_squires That i something I don't have an explanation for--just following the suggestions of those that came before me on this project.


A word of caution about the blog linked to in the first post. I don't know who the author is, Squires claims he wrote it but I see Nigel Tufnel's name at the bottom of page. 

There is a lot of misinformation here that could lead someone astray, or after reading this even avoid starting the modifications. 

"You CAN change inductor gauges but you must monitor changes  to the system impedance, frequency response AND power handling to do so correctly."

This is followed with: "Always compensate for lower DCR with additional series resistance"

When calculating the value of a coil for a certain XO frequency we need a value for XL.

To calculate the XL (inductive reactance) necessary for a chosen XO point the formula is:  XL =2PiFL

Note there is no 'R' in the equation, yet the blog states: "Always compensate for lower DCR with additional series resistance"

The point of using a coil with thicker wire is to avoid heating of the coil leading to thermal compression and to improve damping factor which has a noticeable effect on the bass performance. Adding resistance is to negate $$$ spent on an amp with desirable high damping factor. It's the high DF that controls the voice-coil/cone for clean detailed bass. The only time a low DF will work is when the speaker designer is specifically designing for tube amps. 

I could go on but suffice to say the article linked to appears to be by someone not fully conversant with the workings of the all important crossover.




Hi, the waxed coil you linked to I have found great on tweeters, also the baked varnish coils are pretty good. Not yet tried the foils on the bass section, mainly because of price. When I made my own I used to dip them in warmed up epoxy which sets like a rock and then mount them on a flexible mastic.