For a while, he could hear nothing but a low mumble.

But the door was solid, and all she could hear was a low mumble.

They were talking in a low mumble, perhaps because it was the early hours of the morning.

He managed to keep the vocalization to a low mumble.

His voice came in a low mumble that ended with a chuckle.

When the door opened, there was a silence and then a low mumble of voices.

Each man is talking to himself in a low mumble.

She heard the phone ring and the low mumble of Montana's voice, but couldn't understand what he said.

I heard her dialing the phone, speaking in a low mumble.

There was a low mumble of semi-agreement around the table.