Why is the sound of an alarm siren high and shrill, while the rumble of a distant storm is low and deep? What distinguishes the sound of a double bass from that of a piccolo? The answer to these questions lies in one of the most fundamental properties of a sound wave – its frequency.

Each of us intuitively understands what volume is. A whisper is quiet, while a starting jet is deafeningly loud. But what really gives sound its physical power? What moves the diaphragm of a microphone or our eardrum? The answer is a fundamental quantity in the world of acoustics: sound pressure.

You bought great audio equipment, set up the speakers according to all the rules, turned on your favorite song, and... felt disappointed. The sound is booming, lacking details, and the bass seems to have a life of its own. Where lies the problem when the equipment is top-notch?