Given that the speakers at the Yanni show had a perceptible background hiss, it's obvious that they were not in fact using the best equipment possible. You're w

Given that the speakers at the Yanni show had a perceptible background hiss, it's obvious that they were not in fact using the best equipment possible. You're working from a single data point and drawing a super-unreasonable conclusion. I have heard amplified and recorded violins that sound exactly as they should. Without knowing what they were actually using, it's hard to pinpoint why it didn't sound right, but most microphones and speakers don't have flat responses (so the reproduced sound will be different), the signal could have been EQd to hell and back by the sound guy, maybe the actual violin player was sick and they couldn't get a sub so they just put a roadie up on stage, and maybe they weren't using a microphone but rather a piezo transducer and didn't match its impedance with an appropriate preamp. Way too many variables.