I've just read my reply above and realise it hasn't answered you question - how can I download sound effects from the t3 to the S910? Sorry about that!
1) Put a USB stick in the T3 and make a New Folder naming it something like "T3 Sound Effects".
Copy and Paste the Sound Effects to this Folder. Take out the USB stick.
2) Insert it in the S910.
3) Tab across to the USB, find the Sound Effects Folder, Highlight, Copy and Paste it to the
'USER' section on the S910. Try it out and if it's o.k. highlight, copy and paste straight to
the Hard Drive if it has one), if not, just leave it on your USB stick and if you have a PC
make a backup of the USB on there for safe keeping.
I don't know whether the S910 has a 'Legacy' section, if so you may find all these Sound Effects in there. Your Manual should tell you how to access the 'Legacy' If not, let me know.
Have fun!
Audrey