sound

He turned when he heard the sound of footsteps behind him.  Nobody made a sound.

In trumpets for assisting the hearing, all reverbation of the trumpet must be avoided. It must be made thick, of the least elastic materials, and covered with cloth externally. For all reverbation lasts for a short time, and produces new sounds which mix with those which are coming in.

He looks like he's got it, maybe. Listen to those kids!

There's no maybe about it. That's it, that's the sound.

For let us conſider this Prepoſition as to its meaning, (for it is the ſence, and not ſound, that is and muſt be the Principle or common Notion) […]

Stay within the sound of my voice.