That's why I always continue to use the original coils/inductors that came with Altecs crossovers, and just replace the old caps and resistors.Clean the pots/L-pads and move on to the next project... Replacing the old caps that are 25-30+ years old really makes a huge difference IMO & experiences... And is really all that is needed.It's been 30 years since these old classics have been manufactured thereabouts and in that time there has really been no magic bullet of a crossover tweak (Passive) so to speak.And for good reason most of Altecs good crossovers Model 19/604H's were top notch designs.Of course there are exceptions that weren't so good.But for the most part just replacing the caps is all you really need to do IMHO.