Nope, my hearing is stellar. The QC2 was a gift many years ago and served its purpose as a comfortable, reliable thing that worked fine unamped out of a crap business PC output, sounded appropriately uninvolving and polite for work purposes, and provided much needed isolation and noise canceling. Considering Etymotic ER-4S or ATH-ANC7B at this point because even the M50 doesn't provide enough isolation. The M50 is a significantly more satisfying piece of kit, for me, than the three SAxxxx sets I've owned in my time. I'm also considering the HE-500, but I'm concerned its open nature (or any open cans' open nature) in this increasingly noisy and chaotic world of work and home would have limited usage parameters.
SA5000 for bassheads, awesome!
Of course I was joking, highlighting the point that we all have different tastes. Like I said above amp synergy is important, headphones like the SA need tubes. I see you have a Gilmore lite listed in your sig, I've seen these recommended for the likes of Senn HD650 because they're so transparent... a SA5k w/ Gilmore lite would be a disaster for example. Did you use a tube amp? A HE-500 or Denon D5000 or similar might be more up your alley, they have a warmer, more theatrical approach to music. I found the M50 boring and turned it away when it was sub-$80, I'm not sure what people see in it but goes to show how different we all are.