Screams on 911 call weren't Zimmerman's, forensic expert says.

[Fawke Em]

The panicked cries for help caught on a 911 call the night Trayvon Martin was killed were not coming from shooter George Zimmerman, forensic experts say.

Two leading forensic voice identification experts who listened to a 911 call from a neighbor at the Sanford, Fla., gated community where Martin was gunned down told the Orlando Sentinel that the screams didn't match Zimmerman's voice.

Using sophisticated voice match software, Tom Owen, forensic consultant for Owen Forensic Services LLC and chair emeritus for the American Board of Recorded Evidence, told the Sentinel that there was only a 48% chance that it was Zimmerman crying for help on the tape.

Usually, a positive match rates higher than 90%.

Read more: http://www.nydailynews.com/news/national/trayvon-martin-case-screams-911-tape-george-zimmerman-experts-article-1.1054067#ixzz1qnzimJlB

[dkf]

1. A negative is a 48% chance? That's kind of screwed up.

[Gore1FL]

3. Not a 48% chance, a 48% match,

48% chance implies there is a 1/48 chance that this is Zimmerman.

48% match means that 48% of the voice characteristic match those with Zimmerman.

If a Poodle's and St. Bernard's Bark were analyzed, it might return a percentage of 10%. That doesn't mean the poodle has a 10% chance of being a St. Bernard, but rather that barks of the two dogs have 10% in common.

[slampoet]

8. Thanks for explaining it that way. 48% means that only the gender matches...usually.

[slackmaster]

2. Things will really get ugly if they also say the voice couldn't be Trayvon Martin's

[Gore1FL]

4. He isn't available to provide a voice pattern n/t

[slackmaster]

9. I hope there is a verifiable recording of his voice somewhere

[Fawke Em]

13. I would say that in this day of video on cell phones

that most every parent has that.

I do.

[Fawke Em]

5. This was a newspaper investigation...

They didn't have Martin's voice recorded, so they couldn't compare his voice with the tapes.

[JesterCS]

6. it might have been easy

to get the voice from calling his cell and listening to the voicemail greeting. Who knows.

[Mariana]

7. They may have tried that

and didn't get enough to do the comparison. My cell's voicemail greeting has all of three syllables in my voice. Not much of a sample.

[slackmaster]

10. That's a good point. I hope people understand that this does not constitute "evidence."

Certainly not evidence that would be admissible in a criminal trial.

[Fawke Em]

12. Possibly... but the police could seek him out

to do an investigation. Or could seek out another qualified audio forensics investigator.

That would be admissible in court and has been in the past.

[PotatoChip]

14. Actually, it sounds as if Owen's analysis could be admissible court evidence.

Source: Orlando Sentinel

Owen, a court-qualified expert witness and former chief engineer for the New York Public Library's Rodgers and Hammerstein Archives of Recorded Sound, is an authority on biometric voice analysis — a computerized process comparing attributes of voices to determine whether they match.

-snip-

"I took all of the screams and put those together, and cut out everything else," Owen says.

The software compared that audio to Zimmerman's voice. It returned a 48 percent match. Owen said to reach a positive match with audio of this quality, he'd expect higher than 90 percent.

"As a result of that, you can say with reasonable scientific certainty that it's not Zimmerman," Owen says, stressing that he cannot confirm the voice as Trayvon's, because he didn't have a sample of the teen's voice to compare.

Forensic voice identification is not a new or novel concept; in fact, a recent U.S. Department of Justice committee report notes that federal interest in the technology "has a history of nearly 70 years."
http://articles.orlandosentinel.com/2012-03-31/news/os-trayvon-martin-george-zimmerman-911-20120331_1_voice-identification-expert-reasonable-scientific-certainty

[Fawke Em]

11. Alex Witt interviewed Tom Owen a few minutes ago.

He's a qualified forensic consultant and his services have been used quite frequently by law enforcement:

Thomas J. Owen also serves as the Chairman of the Audio Engineering Society's Standards Group SC-03-WG-12 on Forensic Audio. Mr. Owen is also the Chairman Emeritus of The American Board of Recorded Evidence.

Mr. Owen Worked at New York City's Lincoln Center Archives for eleven years as Chief Engineer. He has appeared on network television and on radio discussing audio and video matters. Mr. Owen Lectures extensively in the United States and has numerous publications in the Forensic Examiner.

Mr. Owen's qualifications as an expert witness have been demonstrated in more than thirty-five states for both prosecution and defense.

http://www.owlinvestigations.com/about.html

[LogicMatters]

15. These "experts" should be fired, or they were misquoted.

The two experts should never be allowed to work in the field again.
You can not compare voice recordings of different words, on a different phone, in a different situation.
Blatantly disregarding their own standards like this.
American Board of Recorded Evidence -- Voice Comparison Standards
http://expertpages.com/news/american_board_voice_comparison.htm
3.3 Duplication of Speech Delivery.

3.3.1 Reading v. recitation. The suspect should be allowed to review the written text or transcription before actually making the recorded exemplars. This familiarity will usually improve the reading of the text and response to oral prompts and increase the likelihood of obtaining a normal speech sample. When a suspect cannot or will not read normally, it is advisable to have someone recite the phrases in the same manner as the unknown speaker and have the suspect repeat them in a similar fashion. Ideally, the exemplar should be spoken in a manner that replicates the unknown speaker, to include speech rate, accent (whether real or feigned), hoarseness, or any abnormal vocal effect. The individual taking the sample should feel free to try both reading and recitation, until a satisfactory exemplar is obtained.

3.3.2 Repetition. Multiple repetitions of the text are necessary to provide information about the suspect's intraspeaker variability. All material to be used for comparison should normally be read or recited from three (3) to six (6) times, unless very lengthy.

3.3.3 Speech rate. Exemplars should be produced at a speech rate similar to the unknown voice sample. In general, the suspect is instructed not to talk at his or her natural speaking rate if this is markedly different from the unknown sample. An effort should be made through repetition to appropriately adjust the speech rate and cadence in the exemplar to that in the questioned recording.

3.3.4 Stress/Accents. Stress includes the emphasis and melody pattern in syllables, words, phrases, and sentences. If prominent or peculiar stress is present in the questioned recording, exemplars should be obtained in a similar manner, if possible. Spoken accents or dialects, both real and feigned, should be emulated by the known speaker. The recitation mode is the better technique for accomplishing this.

3.3.5 Effects of alcohol or other drugs. Since the degree and type of effects from alcohol and other drugs varies from person to person, an attempt to duplicate these vocal changes is not recommended when obtaining the exemplar. If the suspect appears to be under the effects of alcohol or other drugs at the time of the exemplar recording the session should be rescheduled.

3.3.6 Other. If any other unique aural or spectrally displayable speech characteristics are present in the questioned voice, attempts should be made to include them in the exemplars.

[rbrnmw]

17. Welcome to DU enjoy your short stay n/t

[uppityperson]

18. hahahahahahaha. Can't compare different situations? snort, giggle

Seeking the truth, right?

[Ian David]

19. 3.3.1 Reading v. recitation is exactly the opposite of what is true.

Here is a great article you can read (or listen to) on Audio Pareidolia.

When People Talk Backwards
http://skeptoid.com/episodes/4105

When you read what something is SUPPOSED to sound like, your brain usually interprets it as such, whether it is actually true, or not, once you listen to it.

Here is the best example (and by best, I also mean the most fun):

Also:

[Honeycombe8]

16. Yeah, that makes sense. GZ doesn't strike me as the screaming-for-help type. nt