In choral writing the alto line sits below the soprano and above the tenor. The voice itself is the lower female range, though some male countertenors also sing in this register. The tone is often described as rich and warm rather than brilliant.

Alto parts frequently carry the harmony, filling the middle of the texture while the soprano takes the melody. In opera and art song the term mezzo-soprano sometimes overlaps with alto, yet the choral designation remains standard. Composers write for the alto voice with care, avoiding extremes that strain the lower notes or push too high.

Many adult choirs have more sopranos than altos, so the section is valued for balance. Solo repertoire for alto includes works by Bach, Handel, and later composers who appreciated its distinctive color.

• Lower female singing voice
• Sits between soprano and tenor
• Often carries harmonic inner lines
• Warm, rich timbre