We finally had to put her down at age 15 when she developed an incorrigible need to pee on my young daughter's new bed. (Yes, we tried several solutions, including finding her new accommodations. All failed.)
I must say, I haven't missed that voice since we had her put down.
The funniest thing about her was that she was a total coward and made up for it by acting like a badass...I have a spiral staircase system I go up and down to get to my apartment and when she'd turn each of the 4 corners necessary to get to the ground, she'd preemptively hiss BEFORE looking around the corner IN CASE another cat was there, so she always got in the first cuss word in any confrontation...Sounded like a leaky radiator discharging on a timer every 15 seconds till she made it to the parking lot...She loved people though...she'd lean into you if you petted her and rumbled like a hydroracing boat if you gave her the least amount of attention...I miss her alot...but not her voice!;-@