If you have a Debian based system, you most likely have the Synaptic Package Manager.
In the quick filter type in: fluid-soundfont-gm If you get no results add repository of: debian wheeze. main contrib non-free
Check that box after you have file located, and click apply.
This will install the sound fonts to be used system wide.
The sound fonts will be located in /user/share/sounds/fs2
open the LMMS setup and in the file paths for Default sound font file add
/usr/share/sounds/sf2/FluidR3_GM.sf2
In the quick filter type in: fluid-soundfont-gm If you get no results add repository of: debian wheeze. main contrib non-free
Check that box after you have file located, and click apply.
This will install the sound fonts to be used system wide.
The sound fonts will be located in /user/share/sounds/fs2
open the LMMS setup and in the file paths for Default sound font file add
/usr/share/sounds/sf2/FluidR3_GM.sf2