speaker capacitors-----leave alone or does it open pandora's box ?

Those red ones are Audyn Q4 capacitors. I replaced them in my tube preamp with the Audyn Cap Plus  - white and much larger, and the improvement was significant. True Coppers are supposed to be better for certain applications but they have a very long break-in period, especially larger values. Not tried them in speakers. I've also tried Jantzen Z-superior capacitors in a couple of speakers and one other tube preamp and I personally found them more balanced than the Audyns and take less time to even out. I was also told by a couple of (tube) preamp designers/manufacturers that if switching brands when upgrading capacitors you may need to adjust the values to get the improved sound quality. Others with more experience can chime in.  

kosst:

You make lots of statements based on your experience that are pure opinion

Here is your first mistake: it is based on experience and experimentation. That is not pure opinion. I make speakers and experiment with capacitors. Have you?

and they’re not very resistant to scrutiny.

This is your second mistake. The OP can easily scrutinize my suggestions by spending $40 on caps and trying them out.

All I’m saying is look at the actual specs of the things and experiment instead of obsessing about price tags, ad copy claims, and the opinions of folks on a forum. Sorry that ruffles your feathers.

Third mistake, this is exactly the opposite of what you have been saying. Sorry if that ruffles your feathers. In fact you made a number of claims about what matters without discussion about personal experience. You seemed to be relying on information from others without actually trying it yourself. 

Best,

Erik

Erik, as usual you are speaking from experience and I have long valued your speaker posts.  You have a great deal of knowledge born out of your actual building and tweaking experience with speakers.  Thanks for supporting this forum with your knowledge. Much to discover and learn regarding speaker upgrades and it is fun!

+1 don_c55! Cap replacement is for the audio neurotics - and is cheaper than going to a therapist!