I imagine a physicist would invoke entropy to describe the diffusion of pressure waves and vibration into other forms of energy. Neuroscience might explain the propagation of signals from the cochlea into the brain. A psychologist could hypothesise on the influence of music on our mood and ideas. A philosopher might talk about the influence of music on the way we build our society and how that feeds back into our music. In this way, the music never stops, it continues on as echos rippling through through the universe.

It rolls up into the other side of the cassette. Just flip it over.

The best and the worst go straight to your brain and live there rent free.

Unfortunately, nobody has figured out how toget rid of the bad songs that drown out the good ones.

Completely real story

oh when will they ever learn? oh when will they... ever learn

After you listen to a song, the secret police from the RIAA come and lock it up in a small, dank cell given minimal sustenance, until the next time they can send it to some seedy hotel, suburban home, or automobile, to turn a trick and make them some more money, like some sort of whoo-re for the ears.

Where does the light go when you flip the switch?

Check your fridge.

As the waves from ocean, the music crashes on the beaches in your ears

It stays in our brain and we subconsciously put it into new music years later, thereby keeping the industry’s corporate lawyers in cocaine for future decades to come.

You absorb it into your soul and it changes you irreversibly forever.

It goes into your memory. That's why you can remember a song that you heard before.

The Langoliers eat it.

Heat. Everything ends up as heat.

Sounds move very very fast, faster than a runner or a car, so it goes very very far away.

"Ultimately it increases entropy... let me tell you about the heat death of the universe..."

"No, Mom! I'm still afraid of the False Vacuum monster laying underneath my ground state!"

They should show their kid this.

Some of that sound rearranges some of your neurons so that you can listen to Never Gonna Give You Up whenever you read this

The music stays in your head until your forget it. Music only exists in your head

It dissipates into the air like butterflies, or a cloud of dust.

It gets stuck in my head for 3 to 4 days until something newer comes along and pushes it out.

Everyone knows this duh!

Into your heart!

Into darkness, my old friend.

I've come to talk with you again.

Because a vision softly creeping

Left its seeds while I was sleeping

And the vision that was planted in my brain Still remains

Within the sound of silence

"Everywhere, all at once. That's why if you put your ear close to speakers it might collect too much and that can hurt your ear"

into our minds and into our hearts

I'm not a scientist by a long shot, but my understanding is that sound if indeed a wave, carried by a medium (air, water, etc). Upon hitting your eardrum, this wave is converted by your eardrum and your auditory nerve into signals your brain decodes. The remainder of the wave continues though, until it runs out of medium, hits an obstacle (basically another medium) or dissipates. Again, just my layman's understanding!