SANFORD, Fla. - The hearing dealing with audio experts in the George Zimmerman murder trial stopped for the day around 8:30 p.m. Monday.
A rebuttal witness for the prosecution will be heard from at 4 p.m. Wednesday.
Judge Debra Nelson heard from Dr. James Wayman, from San Jose State University, a nationally known voice recognition expert who teaches the science of human identification.
The hearing deals with whether the jury should hear what the state's audio experts have to say about what is heard on a 911 call made the night Zimmerman shot and killed 17-year-old Trayvon Martin.
WFTV legal analyst Bill Sheaffer said it's more important for the defense to keep out the state's experts who said it was Martin who was calling for help, because that's who the jury will hear from first, and it will be powerful.
“The defense will want to capitalize on the conflict among the experts to say, 'Look, you really can't tell who it is on the tape,’” said Sheaffer. “’By the way, you can listen and form your own opinion.’"
An audio expert for the defense, Peter French from the United Kingdom, testified earlier this month via Skpe videoconferencing, telling the court that the audio recording from the 911 call is not sufficient enough to be compared and analyzed.
"That recording isn't even remotely suitable for speaker comparisons if submitted as that as question. We wouldn't have accepted it," said French.
Another defense expert, George Dodditin, testified Saturday afternoon and agreed that the audio recording is insufficient for comparison.
The audio experts for the state and the defense have strongly differed in their opinions of the brief audio clip.
One of the state's experts who testified Friday afternoon, Alan Reich, said that he repeatedly listened to the 911 call that recorded someone in the background yelling for help right before Zimmerman shot and killed 17-year-old Martin. He said he used electronic equipment to conclude that it was not Zimmerman's voice.
"The very high-pitched, very loud screams, that's all we could find screaming. Those were not George," said Reich.
WFTV legal analyst Bill Sheaffer said that even though the state experts' conclusions are not considered scientifically solid, the judge will likely let them testify because the standard of admissibility is not that high.
Reich said he heard words in the recording he attributes to Zimmerman. No one else, including the FBI, has reported hearing those words.
The state's other expert, Tom Owen, also testified on June 7.
Owen said he used his special audio analysis equipment and listened repeatedly to the screams for help. He said he concluded that it probably was not Zimmerman's voice, but he said the background noise interference and the limited speech sample available, seven seconds, makes it impossible for him to say for sure.
"It affects the strength, the veracity of my overall conclusion. I had to drop from 'positive' down to 'probable,'" said Owen.
"If the defense is able, in cross-examination in front of the jury, to make the points they made in front of the judge, the jury may have a stretch in considering this in deciding a verdict beyond every reasonable doubt," said Sheaffer.
Both experts said they compared the 911 screaming to Zimmerman's re-enactment of his screaming.
An FBI expert testified Thursday that there wasn't enough clear sound on the 911 recordings to determine whose voice it was. Hirotaka Nakasone also said the concept that individuals have unique voiceprints that identify them is misleading.
"No one can speak in the same way twice," Nakasone said.
The screams captured on the 911 calls are crucial pieces of evidence, since they could determine who the aggressor was in the confrontation. Martin's family contends it was the teen screaming, while Zimmerman's father has said it was his son.
Zimmerman has pleaded not guilty to second-degree murder in the case.
Follow Kathi Belich on Twitter at @KBelichWFTV for gavel-to-gavel coverage of the trial.