Hi Janilyn,

You didn't give any specifics in your question so by "magix online" I'm assuming you mean one of the download versions of a Magix music program.  I use Music Maker 14pe, which allows you to click "Help" and then "Download synthisizer and soundpackets..."  Clicking that opens your browser to a specific web site where you can download several very large files.  After getting them all, you run each file which then installs the synths and sound pools.

I downloaded the trial version of Music Studio and it worked basically the same way, although it provided different files than Music Maker.

Hope this helps,

Tim