Our entire visual system is a massive brain hog. Fifty percent of the cortex is devoted to processing visual information.
When you close your eyes, much, but not all, of that goes offline. And very shortly after you've closed them for a few minutes, the brain suddenly decides that auditory information is much more relevant now that you can't see anything.
We begin to hear distinct sounds that were just vaguely, if at all, in the background just moments ago. And you can, with minimal practice, dial up the intensity of awareness now devoted to listening.
There's a raga playing somewhere in the far distance. Crows are being crows. The murmur of engines of various types. Air coming in and out of my nose.
There's cacophony, too -- never pleasant, but just there.
It helps to pay attention to what we're hearing because it seems like our ears need some TLC. We have some agency as to what we let in and out, and we should exercise it when we can, but most of the time sounds are simply erupting all around us, everywhere, far beyond our control. When sounds erupt, you can't not hear them. They're just there.
I like the idea of caring about our soundscapes, and making conscious attempts to upgrade them. Some upgrades might include your most beloved music, and maybe earthy sounds like rain and wind. And there are always insects and birds and mammals, especially primates, making their presence known. Footsteps and voices of the people you love, if you're lucky enough to hear them.