Klipsch and Capacitors

Thanks for the advice! 

+1 for only electrolytic caps are likely to wear over time.  

There's a large cap on the woofer.  If that's electrolytic you should be careful replacing it with a modern as the difference in ESR may be significant.  

For the tweeter caps I might suggest you try an Audyn 0.1uF TruCopper bypass.  About $20 each.  

@maprik ,  I have to ask.  How did a pair of KG4s go unused for 40 years?  I have 2 pairs BTW.

If it was me ALL the old stuff inside would be replaced with modern components.

Crossover

Terminals

Wire

Add additional dampening if needed.  But heck, that's the way I am.

Hello maprik!  Almost every company uses cheap parts in their crossovers. Replace just about everything in the crossovers, except maybe the board their on, with high quality parts.  Avoid ferrous metals anywhere in the signal path, including the connectors on the speaker wires. Test everything with a magnet, even the nuts and washers on the binding posts. It may sound exteme, but you will be pleasantly suprized if you do it. Be prepared to spend $100 or so for each of the left and rignt speakers. (If you have a surround sound system, do 'em all as finances allow.)  I recently upgraded all the steely bits in a four way system and was stunned at the improvement. Enjoy the music!