Watch Tuesday's presidential debate and CNN's exclusive expert analysis starting at 7 p.m. ET on on CNN TV, CNN.com and CNN's apps for iPhone , iPad and Android. Web users can become video editors with a new clip-and-share feature that allows them to share favorite debate moments on Facebook and Twitter. Visit the CNN debates page for comprehensive coverage.
Washington (CNN) -- President Barack Obama and Republican challenger Mitt Romney step into a more free-wheeling town-hall style debate on Tuesday night, a setting that has given the two coolly intellectual candidates some trouble in the past.
Both will have to recalibrate their approaches from their first encounter on Oct. 3, which was won by Romney.
"I think Obama assumes he will do better in town hall debates because he has an advantage on empathy," said Emory University political science professor Andra Gillespie, adding that Obama is going to have to "show a little more passion and fire in his belly."
Romney could be less aggressive, which earned him points in the first debate, and focus more on trying to narrow the likability gap.
"Because Romney is gaffe-prone he is going to do everything he can to come across as warm and empathetic, Gillespie said.
CNN Chief Political Correspondent Candy Crowley will moderate the second debate at Hofstra University in Hempstead, New York. She is first woman to do so in two decades.
The town hall format presents challenges and opportunities for the candidates, Crowley said. Both have held a number of town hall forums during the campaign season — exchanges that haven't exactly sizzled, political experts say.
That's because Obama tends to become professorial and Romney stiff in such settings.
"The danger of the town hall is that you're getting (questions) from the audience," said Melissa Wade, a debate professor at Emory University. "It's either because they're either not good or they are so rehearsed the responder has a hard time."
Other candidates have struggled in town halls.
Television cameras caught then-President George H.W. Bush when he looked at his watch during a town hall debate in 1992. In 2000, Vice President Al Gore got in GOP rival George W. Bush personal space which made for an awkward moment.
The unpredictable nature of the questions also has perils, she said.
In 2004, President George W. Bush struggled to answer a woman's question on three wrong decisions that he'd made. That debate was also full of testy back and forth — the types of exchanges that spell trouble for politicians, political experts say.
In the last presidential town hall debate, GOP nominee John McCain wandered across stage while Obama, then a senator, answered a question.
"I worry for Romney that this is where he gets excitable. I wish someone would tell him to count to three before he opens his mouth. Informal leads to more quips," Wade said. "Excitability is not likability."
Though according to polls Obama ranks higher in the likability department, he, too, struggles in town halls.
"It's his worst format," Wade said. "It was not as pronounced as McCain wandering around. Obama in a town hall is more long winded. He just can't help himself."
Obama came up against his long winded nature during a CNBC town hall event in 2010 when then-Obama supporter Velma Hart told the president she was "exhausted" from defending him.
Instead of answering Hart's question directly, Obama talked around it for four minutes.
The candidates also will have to work to connect with both the television viewing audience watching at home and the group of voters sitting in the room.
"They are going to have roughly 80 people, as I understand it, looking at them in addition to me. You know and I know it is very easy for politicians to run over a reporter — they don't care," Crowley said. "There is no price to be paid for being rude to a reporter, not answering the question. But 80 undecided voters looking at you, and some of them getting up and going, "Well, what about this?" It's just harder to dodge."
A CNN/ORC survey conducted just after the first debate suggests that it didn't change opinions of the president. Forty-nine percent of debate watchers said they had a favorable opinion of Obama before the event, and that number didn't change afterward.
It was pretty much a similar story for Romney, whose favorable rating among debate watchers edged up two points, from 54% before to 56% after.
Still, both could use the less predictable nature of the town hall setting to their advantage, political experts say.
"This town hall forum offers President Obama a chance to communicate in a different way than has been expected and more effectively. Everyone expects him to come out swinging. ... I think it would be more creative and effective if he focuses on audience members and the middle class and his plans for the future and why they are more effective than his opposition," said David Gergen, a senior political analyst for CNN.
Romney too could use his strengths to score points.
"Romney's strength is dignity," Gergen said, adding that the GOP nominee seemed to relish and fare well when he was on the offensive during the first debate. "He's got to bring the same level of energy and go more indirectly with the president through the person he's talking to."
CNN Political Editor Paul Steinhauser contributed to this story