The revised the trailer because of possible legal ramifications.
Ginny Owens, the original woman behind the song 'Be Thou My Vision', which is the song used in the teaser, posted this on her website around the time the Saw V teaser hit the internet:
'Dear Friends,
Some of you have undoubtedly come across a movie trailer for the horror film Saw V with one of my songs as the background music.
Although I do not have a say in where and when my previously recorded music is used, I can tell you that a request was submitted to Rocketown records for the use of this song in the movie trailer, and after reviewing the trailer, Rocketown denied the request.
At this point, we are unsure of how and why this version of the trailer has appeared on some websites. We hope to solve this matter as quickly as possible. Thank you for understanding.
—Ginny Owens'
Then she posted this a short while later:
Sometime during the afternoon of Friday, July 25th, my voice on 'Be Thou My Vision' was replaced by another singer.
The track still sounds nearly identical, and most websites continue to 'credit' me for it, but the background music for the Saw V trailer is no longer my original version of 'Be Thou My Vision.'
Thanks.
—Ginny Owens'
Basically the guys over at Lionsgate requested the song and were denied, so they went and got another woman to sing it for the teaser! The version heard in the teaser was a different woman, not Ginny Owens.
However now that it’s a man singing it, I wonder why they changed it. If another woman sang it and apparently there still was an issue that caused them to have a man sing it, isn’t there still the same issue? Apparently not!