Have you spoken to Ian about the possibility of a component change in perhaps a crossover in a speaker or another change in the mid drivers? does one or both of your speakers get direct sun exposure during the day?
I have a pair of vintage Cerwin Vega 12T towers in walnut veneer which were purchase in 1975. Over time they changed in sound quality from what I had started with. Also one speaker which was near the windows faded quite a lot from the sun UV.
I ended up having the crossovers serviced and the woofers re-coned at one point and it made a huge difference. However the mids were not serviced and with more time, they started to sound very harsh to me. I was considering more service work, howver Cerwin Vega was not the same outfit, they had been purchased by the Chinese and replacement parts was out of the equation.
I spent less time using my system as it just wasn't pleasing any longer, then last year I took a lightning hit which blew outlets out of the wall and rocked the circuit with my sound system on it. I lost everything, including the CV 12T's; the speaker wire terminals on one speaker were literally blown apart.... the speakers were toast. OK, finally upgrade time!
Thanks to a good insurance policy, I ultimately replaced everything with a Parasound A51 amp, Anthem AVM60 preamp and Bryston Model T's along with other items I decided to go up on too. All I can say is, wow, I had no idea what I was missing in sound as the degradation of the older equipment was so gradual that you don't notice it until one day it just grates on you for some reason.
Now I keep the speaker by the windows under the black cover bag which comes with it until I use it. I have to keep that beautiful wood veneer looking fresh.
