Yes it is.
Juries hate complexity, and they get easily confused.
The screams are not an issue in this case. Trayvon's criminal background is not an issue in this case. Purple drank is not an issue in this case. Zimmerman being kind to negroes is not an issue in this case.
Zimmerman is charged WITH SECOND DEGREE MURDER. He has several affirmative defenses, including, most importantly, self-defense.
ANY EVIDENCE ABOUT ANYTHING EXCEPT WHAT HAPPENED WHEN HE WAS ON THE GROUND WITH MARTIN BEATING HIM IS IRRELEVANT, and, not only that, no such evidence could possibly help him. That the guy he shot was a scumbag is not a defense. That the guy he shot was casing houses for B&E is not a defense. That the guy he shot was doing drugs is not a defense. That the guy he shot was a wannabe gangsta and imagined himself as "no_limit_nigga" is not a defense.
If Zimmerman can prove that he was being beaten in a manner that could result in his death and that he could not escape other than through his perfectly legal use of deadly force, nothing that the State does or says matters.
Is it just possible death or possible death or bodily harm ?
He has pictures of harm!
That should be it in a nutshell. In a sane world.
OK, well, he was on the ground screaming for help, if they could prove it was Z screaming, I think that would be a good thing.
The bad thing is that the prosecution's expert will either say it was Travon screaming or that they couldn't tell.
The defense's expert will say it was Z screaming or that they couldn't tell who it was.
I do a lot of work with audio equipment (high end tube stereos) and if I had a decent sample of both of their voices and also the 911 tape, I could run them through a spectrum analyzer and it would be obvious which one is closer. Unfortunately, the noise that I bet is on the 911 tape would result in several spikes as well and voice calls frequencies are limited to 3000hz so no harmonics either.
Now I'm using thirty year old equipment because I don't need state of the art parts because I'm working with old (tube) technology. I have no doubts that the tools the police (and experts on both sides) have access to equipment which will eliminate the noise or bring the actual voice & screaming up so its S/N leaves the noise in the dust. No doubt they also have equipment that can easily determine whose voice is screaming but we have a small problem getting a sample from Travon for some reason.