Last Friday I was working in my studio as normal and noticed the sound from my system sounded terrible. No bass and very tinny, no image depth etc etc. Tried an SS amp in lieu of my valve amp: same result. I thought maybe the mains quality had suddenly gone bad. Didn't improve all day. Tried the main system in the house in the evening, also sounding terrible with exactly the same symptoms. Thinking that was a bit weird and the mains must really have taken a dive I forgot about it and didn't listen to anything else over a busy weekend. Back in the studio Monday morning sound system sounds fantastic again, as does the system in the house in the evening. Scratch head, then put two and two together. On Thursday evening I had a flu vaccination and felt very fluey over the weekend. By Monday this had gone. Clearly the vaccination had affected my hearing... One wonders how many people's supposed systems' problems might be temporary or longer hearing issues.............