You are speaking of a classical concert. Even at Carnegie Hall the musicians come on stage and tune their instruments and then the conductor taps his baton and the program progresses. I assume you were speaking of their tuning---a normal thing.   

Did the orchestra you were listening to complete the concert as billed in a professional manner? In a professional interpratation is a better phrase.

Folk concerts (shows) are a bit different. More informal---and many artists (sometimes irritating) "tune" all the time between pieces. Though, I notice the real pros do not---the more amateurish ones do that and talk about it and expound on that, no less. That is, however, different than your comments re: a classical concert.   


Bill Hahn