B1
not forceful, loud or easily noticed
Dictionary examples:
The teacher's soft voice made even math sound like a lullaby. (0.0)
His soft snoring was so gentle, even the mice couldn't hear it. (0.0)
His soft laugh was so quiet, only dogs could hear it. (0.0)
She likes soft pastel colors. (27.2)
a soft voice/sound/music (30.9)