carrying voice; well-projected voice
Describes a voice that travels clearly and is easily heard, even at a distance or in noisy environments. Often used positively for speakers, singers, or actors.
She has a carrying voice, so you can hear her clearly even at the back of the classroom.
A stage actor needs a well-projected voice.
A set phrase combining よく (well) + 通る (to carry, to travel) + 声 (voice). The literal meaning is 'a voice that travels well'.