While I don't have Cornwalls, my highly modded Klipschorns benefited greatly first from tube amps, both push pull and SET, 300B SET being my favorite pairing. My diy mods to crossovers also major upgrade. I couldn't live without both, but I'd say amp is place to start, whatever crossover mods you do won't be fully realized without the proper amp. Damping of horn is another good mod.
Cornwall IV – new amp vs crossover upgrade
I recently bought Cornwall IVs and basically I´m very happy with them – they just sound very pleasant. And I haven´t even upgraded to another amp yet which seems to be the next logical step. When I was in the store I tested them with a class AB and a hybrid amp and I could already tell that the hybrid made them sing. Currently I´m using an old, small Rotel amp and they do sound great with it but I know there´s plenty of room for improvement.
Having read a few things here and there, I´m wondering which has the bigger impact: a new amp or a new set of crossovers. Sure, it´s all individual but with people raving about non-Klipsch-crossovers and other improvement (for example damping the horns as suggested by the Boston Audiophile), I´m not exactly sure what should be next. Would a nice tube amp make a crossover upgrade unneccessary? It´s hard to tell from what I´ve read.
As much as I like them, I feel right now they are lacking a bit of overall warmth. On the other hand the highs are a bit too pronounced and detailed for me which led me to turn down the highs on the amp a bit. There are some recordings that just match the current setup and listening to them puts a big smile on my face. And I just feel that this can be extended to more albums.
Thanks in advance for help and suggestions!