Tweeter Capacitor

My recommendation is to get an 0.1 uF Audyn TruCopper bypass cap to put across it before you consider a complete cap replacement.

Thank you, but the qualitative contribution will not be the same level than a replacement.

That's along with OP, there is a very good reason for the frequency collector .1 or 01uf to be added along with the 6.8uf. That copper bypass is a real good choice. They are directional too. The arrow towards the - or away from the +. It will work either way, the difference is the outside of the cap wrap vs the inside. They can make noise, I've never heard it though.

It's easy on a large cap. Just get a DMM and see which leg has less resistance when the other probe is on the outside of the cap. That is the way out on ALL non-polarized caps..

The Duelund CAST Cu is very well regarded as top of the pile. I’ve not heard it. I have V-Cap ODAMs. The Miflex is very good too but maybe a little brighter.