It's handy to have extra instruments available in your ARIA Player. Besides all the Garritan Libraries, and other SFZ instruments you may find online, you can also make use of SoundFonts which can still be found free all over the internet.
Using this program, you can easily convert those SoundFont sf2 files to SFZ files that you can import into ARIA:
That free program has many options, but you don't have to do anything more than simply open an sf2 file, leave everything as it is, and export it as an SFZ file.
That's all there is to it! You may want to take a look at the program's controls, and fine tune your results, but you don't have to.
Instant access to all sorts of instruments you may currently be missing and wish you could have sitting alongside your Garritan instruments.