The symphony allows a wonderful experience. Sitting in an acoustic capsule, one can either hone in on the reverberations of individual strings or lie back, stretch their arms, and enjoy the harmonic story drumming their tympanic membranes.
What allows you to do this? The same system that is keeping you - hopefully - from falling asleep while you read this article: the Reticular Activating System (RAS).
First: where is the RAS? There is no clear answer, because it is a neuronal network that spans most of your brain. However, if each wire of the network had it's own "detonator", or bundle of neurons, the detonators would all lie in the brain stem. Feel, if you will, where your head meets your neck. If you were to follow an upward trajectory from your finger into your head you would meet your own brain stem.
Like a stem of a budding seed, this organ is the bridge between the spinal cord and the brain. The Reticular Activating System plays a role in habitual action. A regulator of heart beat, RAS neurons also modulate pain and control select reflexes.
As the symphony ends with a spotlight, do not forget you own a far more powerful tool of focus.