This is a button/knob combo in my Honda Civic. The button is labeled “TUNE FOLDER PUSH SOUND”
Tune: When in radio mode, rotate the dial to tune to another frequency.
Folder: When listening to an MP3 CD or an iPod, change the folder, playlist, artist, album, etc.
Push Sound: Push this button to change sound setting: treble, bass, balance, fade.
This button is not exactly all that intuitive. Then again, how would you make it more intuitive? You could give it a more general label that encompasses its various functions, or include a little radio and CD icon next to their respective commands. That’s far from perfect, though.
Touchscreens have their own problems with a lack of tactile feedback, but perhaps a button with a changeable face that would be context sensitive. If you’re listening to the radio, it says Tune. Switch to CD mode, it says Change Folder. Something like a high-contrast e-paper display may fit the bill.
For now, I wonder how many Civic owners really understand Tune Folder Push Sound.