OK, if we are talking symphonies using an orchestra as the question then this puts a very different slant on the question. I have had season tickets to the symphony for over ten years and have attended hundreds of concerts. By and large symphonic concerts are not loud. Most of the time are interludes between brief very loud crescendo. So, you are asking about the rare crescendo. A great system must be able to handle them. But most of time you will be listening to music and much lower levels.
I mentioned recently, my seats were 7th row center and I would go home and set my system to reproduce the whisper from the silence of some of the great openings to the crescendo to be what I heard at the concert. I use this setting to start with when listening to classical music... or other where I want to duplicate "live in the concert hall". Obviously there is variation in recording.
But still... 95% not loud.
When I first saw the question... I was thinking typical mixtures of jazz, rock, world....etc.