If glasses are adjusted for varying eyesights, why isn't the same logic applied to our ears? Today, most music players (that's probably your phone) are designed with a one-size-fits-all standard -- the manufacturer adjusts the audio tone and left/right balance to what might suit most people.
It turns out, however, there are differences in our hearing, including unique nuances in balance and processing.
Some phones do let you dig into accessibility settings to adjust left/right balance, but the Galaxy S4 might be the first phone that actually adjusts the audio output to your needs automatically.
Buried in the S4's Sound settings is a feature called Adapt Sound, and it's Samsung's prescription antidote to the one-size-fits-all model that robs music lovers of a complete (and accurate) listening experience. With Adapt Sound in play, the output audio will be customized for your ears.
To access the feature, head to Settings > My Device > Sound > Adapt Sound. You'll be introduced to the feature and you'll be asked to settle into a quiet spot. Plug in your headphones and hit Start.
Immediately, you'll be taken through what's basically a hearing test. High- and low-pitched beeps will play, and you'll confirm whether or not you hear them. It's a judgment of your hearing, but also of your headphones. (So, don't get upset if you don't always hear the beep.)
When you're finished, two graphs will appear, one for your left ear, and one for your right. Take a look at them to get a visual sense of what your hearing capabilities are like with and without Adapt Sound. The x-axis shows pitch (frequency), and the y-axis displays hearing ability.
If you're skeptical, you can preview what the sound output is like with and without the Adapt Sound adjustments. Below the graph, hit "Preview Adapt Sound" and toggle between Original and Personalized to hear the difference.
Back in the settings window, you can tell Adapt Sound when to personalize the sound output. Below that, don't forget to indicate your "frequently used side so that it can "adapt" when you've got your phone to your ear.
Revisiting the setup
As Samsung explains, the results produced from setting up Adapt Sound in a very quiet environment should let you get away with never touching the feature again. But if you want to get the most out of the feature, take the short hearing test again when you get new headphones or settle into an entirely new environment.