He added a dash of regret to his voice.

"Yes," he said, and then remembered to add an air of reluctant tragedy to his voice.

She added with a nasty little edge to her voice: "Just remember you're not a passenger, that's all."

As a result, an echo of similar level was added to Quagmire's voice in order to equal both voices out.

"Let me kill you," Susan added a bit of a grunt to her voice.

In the second year, she had added action to her voice, hoping to show them a better way by example.

He even added a token gravity to his voice.

It was a powerful combination, which added depth and resonance to his voice.

Adding a teasing quality to his voice, he added, "I'll let you decide what to do with the data."

The famous engineer's highland roll added a melody to his voice.