I am using Jaksta 1.5.1 with OS X 10.11.16. When I download a vimeo video using Chrome, there is no sound. And using Safari it won't download at all. I've tried multiple videos and the same thing happens. Here is a link to an example of such a Vimeo link (I know there is supposed to be sound because it is one of my videos that I uploaded to Vimeo):
I have just responded your email ticket regarding the upgrade.
Upgrading should resolve your problem, as we built a fix for Vimeo into Version 2 a while ago.
Please let me know if continue to have problems.