Perhaps there is an English word, such that describes someone or some animal producing low sound of pain? So instead of screaming, there can be what, moan? Groan? But that does not quite fit, because I need to describe in a poetic way the quiet sound of piano when you step on left pedal. Hum would do, but humming has nothing to do with pain, so I cannot use that. Maybe there is a word in English that suits what I need..
