Resonance is a phenomenon that occurs when a system is driven at its natural frequency, causing it to oscillate with greater amplitude. Some examples might include the ringing of a bell, hitting that one resonant note while singing in the shower, tuning an old fashioned radio, or the port (or passive radiator) on a loudspeaker.
Resonances are both wanted and unwanted. In musical instruments like guitars, violins, and pianos, resonance is essential for amplifying sound naturally (determined by the size and shape of the instrument's body). In a listening room, sound waves can bounce off the walls and mix together at certain frequencies, depending on the size of the room. This can make some sounds louder, resulting in an uneven and distorted audio quality.
Interestingly enough, resonance is not limited to physical phenomena. Think of your emotions. What you like and dislike has everything to do with what resonates. I might like chocolate while you prefer vanilla. That's because chocolate resonates with me, and for you, vanilla.
So, the next time someone looks at your newest stereo acquisition and wonders what planet you're from, just understand it's ok. It simply does not resonate with them.
We all resonate at different frequencies.
It's what keeps all this so interesting.