Veteran investigative journalist Bob Woodward on Wednesday said a likely reason Hillary Clinton lost young voters in Iowa to her main Democratic rival is because she has a harsh tone that comes across as insecure.

"I think a lot of it with Hillary Clinton has to do with style and delivery, oddly enough," Woodward said on MSNBC's "Morning Joe." "She shouts. There is something unrelaxed about the way she is communicating."

Show co-host Joe Scarborough agreed.

"Last night I was watching her and I said to myself, has nobody told her that the microphone works because she always keeps it up here," Scarborough said.

"I'm sorry to dwell on the tone issue, but there's something here where Hillary Clinton suggests she's almost not comfortable with herself," Woodward said. "And, you know, self acceptance is something you communicate on television."

He said Clinton could appeal to younger voters if she would "lower the temperature" in her voice, explain her record and "get off this screaming stuff."

Exit polling data from the Iowa caucuses on Monday showed that Clinton lost younger voters by 70 points to Bernie Sanders, an independent Vermont senator who describes himself as a Democratic Socialist.

Conservative Wall Street Journal columnist Peggy Noonan said a similar thing about Clinton's speech-making voice.

"She is especially poor at the podium, where, when she wants to emphasize an applause line, her voice becomes loud, flat and harassing to the ear," Noonan wrote in January. She compared Clinton to a "landlady yelling up the stairs that your kids left their bikes in the hall again."