Head Voice vs Chest Voice
The two primary vocal registers: chest voice (low, speech-like, fuller body resonance) and head voice (high, lighter, resonating in the head).
Chest voice is your speaking voice's natural register. You can feel it: place your hand on your chest and hum at a comfortable low pitch, and you'll feel vibration. It's the register most pop, rock, R&B, and country verses live in, and it's where most singers feel strongest. The downside: untrained chest voice runs out of range somewhere in the upper end (around F4 for tenors, B4 for sopranos) — push past it and you strain.
Head voice is the register above that, and the vibration shifts to the head/skull (especially the forehead and crown). It's lighter, more flutelike, and traditionally associated with falsetto in male voices and the upper soprano range in female voices. Head voice sounds airy and less powerful at first, but trained singers can develop tremendous strength and color in head voice — it's where the high notes in opera, musical theater, and many pop ballads live.
The art is in blending the two registers smoothly across the passaggio so listeners can't hear the seam. Mix voice — sometimes treated as a third register, sometimes as a coordination between the two — is what makes a Mariah Carey, Adam Lambert, or Whitney Houston riff feel like one connected voice from low to high. Building that blend is months of work, but it's the single biggest unlock for serious singers.