SOS Help me modify this vintage crossover

[Cryptic]

Hey!

 

New to this forum and figured this might be the place to come. I've recently restored a beautiful set of Goodman 3 way speakers from 1971, these things sound incredible! But when replacing the capacitors, I noticed that the 15" subwoofer bypasses the entire crossover and is hooked up directly to the +- input. 

I'm assuming this isn't normal, and I'd like to piece in a capacitor and or inductor to limit the high end frequencies getting to the sub.

Sizing the components and figuring out how to piece them in is what I need help with. I'd love to know the science behind sizing crossover capacitors and how people generally go about designing/redesigning them. 

 

I've attached a roughly drawn line diagram as well as not-so clear image of the crossover itself for reference. 

[StephenJK]

I fully restored a pair of 1976 Klipschorns a few years ago.  While tempted, I decided to follow the design of the crossover designed by Paul Klipsch and replaced the caps while keeping the coils and zeners but changing the layout to suit.  

 

Crossover design is something that goes beyond your basic inductive/capacitive electrical knowledge set and moves into how that relates to how the load will respond to a certain frequency range.

 

Meaning - the original design may or may not be optimal - but you shouldn't presume that it isn't.  

[audiobomber]

On 6/4/2022 at 4:06 PM, Cryptic said:

New to this forum and figured this might be the place to come.

Actually the place for this kind of advice is diyaudio.com:

https://www.diyaudio.com/community/forums/multi-way.6/

[davide256]

The driver at that size is likely its own crossover... rolls off on its own. When designing a crossover, the first thing you need to know is the natural frequency response of each driver,

its impedance and whether it alters phase.

[MarcelNL]

I suggest to start here;  https://site.diy-loudspeakers.com/speaker-design-construction/36-dickason-the-loudspeaker-design-cookbook