VirtualMIDISynth is a free, lightweight and efficient SoundFont player for Windows.
It is implemented as a Windows multimedia user driver, so it is directly accessible as a standard MIDI out device (no need for a virtual Midi port).
Download JJazzLab-SoundFont.sf2 from the Musical Artefacts web site
Download and install VirtualMIDISynth from the CoolSoft web site Accept all installer default settings.
Load the Soundfont in VirtualMIDISynth Click on the pen icon if you need to adjust the default volume (0-500%) of the SoundFont.
Start JJazzLab and go to Options/Midi, set VirtualMIDISynth as the Midi OUT device
Go to the output synth editor and apply the preset VirtualMIDISynth