Updated, 4:12 p.m. | On the recording, Dianne Defontes’s voice is calm but dramatic as she recounts the moment the south tower went down.

“The lights flickered,” Ms. Defontes says. “This tremendous roar. And the stairways shook. And we’re holding on to the banister and the building is shaking and no one said a word. It was silent until the noise had stopped. And that’s when we were very afraid.”

Ms. Defontes, who was working on the 89th floor of the north tower on Sept. 11, is one of a dozen survivors, victims’ relatives, first responders and others whose recorded oral histories can be heard starting Thursday at the National 9/11 Memorial and Museum’s preview site at 20 Vesey Street.

The preview site, a placeholder until the museum proper opens in 2012, is also displaying a rotating exhibit of artifacts. The first is a red auto-racing jacket owned by Karen Hawley Juday, an administrative assistant at Cantor Fitzgerald and 9/11 victim, donated by her fiance, Richard A. Pecorella.

“Although information about 9/11 abounds in the copious first-person interview transcripts that exist in archives and online, it’s the emotion of these events that can be felt, most immediately and intimately, by listening to human voices recounting their experience,” Jan Ramirez, the chief curator at the museum, said in a statement. The museum has about 400 oral histories in its collection and will rotate the ones in the listening booths.

The preview site, which opened last August and contains renderings of the permanent memorial and a timeline of Sept. 11, now has a listening booth where visitors can hear the oral histories and record their own.