continuous murmur
machinery murmur

Where before that way had been silent, now there was a continuous murmur of sound.

However, continuous murmurs can not be directly placed into either category.

There was a deep, continuous murmur from the cows like the voice of the earth talking to itself at twilight.

There was a faint continuous murmur of distant traffic.

And there was a sound, faint, distorted perhaps by the acoustics of this place, but keeping up a continuous murmur.

She could hear the river running below in the darkness, making a soft, continuous murmur beneath the singing of the joglar.

Since aortic pressure is higher than pulmonary pressure, a continuous murmur occurs.

A patent ductus arteriosus may have no symptoms, beyond that odd, continuous murmur.

There was a sound of light regular breathing and a continuous murmur, as of very faint voices remotely whispering.

There is, consequently, "a kind of continuous murmur or growl beneath middle-class life in India, and this noise never gets recorded".

The mutter of the city came up to her from below, a continuous murmur of great cars that moved in the street, effortless, continuous.

Now he could hear a continuous murmur of voices, laughter and the thud of hooves, coming through the remaining screen of trees.

The night had been exceedingly still, but as I advanced I became conscious of a low, rumbling sound, a continuous murmur, somewhere in front of me.

A low, continuous murmur, like that arising from a full, but gently flowing river, came to my ears, intermingled with the peculiar hum of multitudinous human voices.

The men pressed on in silence, the soft thudding of their feet and the rattle of their sidearms filling the air with a low and continuous murmur.

Glancing in, I saw a line of little green baize tables with small groups of men sitting round, while at one side was a longer one, from which there came a continuous murmur of voices.

There was another silence in which they heard the continuous murmur of the river; then Fanshaw said, in a doubtful and perhaps disappointed tone: "Then you don't think there is anything in the tales of the tower in flames?"

A curious yet not unpleasant drowsiness stole over me, in which I heard the humming of the bees at the open window, the singing of the birds, and the voices of people in the hotel gardens, all united in one continuous murmur that seemed a long way off.

He had a habit, Mary remarked, and she had never noticed it so clearly before, of letting his sentences tail away in a continuous murmur, whereupon he passed into a state of abstraction, presumed by his children to indicate some train of thought too profound for utterance.