A soundfont is just a collection of sound samples. There are different file formats used to store libraries of sound samples, such as the SoundFont, GigaSampler, and SFZ formats. Many free soundfont files are available on the web; some are for very specific instrument sounds, like acoustic piano, or electric piano, or drawbar organ, while others are for a broader range of instrument sounds.
Timbres of Heaven is a large soundfont for a broad range of instrument sounds, compatible with the GM, GM2, GS, and XG soundsets or patch lists. What this means is that you can use the GM, GM2, GS, or XG Bank Select and Program Change values to select between the different sounds in the soundfont. It does not mean that Timbres of Heaven contains the actual GS and XG sound samples which are used by Roland (GS) and Yamaha (XG), because those sound samples are proprietary. Nevertheless, you can use the Timbres of Heaven soundfont to play MIDI files which have been programmed to use GM, GM2, GS, or XG voices, because Timbres of Heaven recognizes and responds to the Bank Select and Program Change values used by those soundsets.
Free MIDI SoundFont, Karaoke, Timbres Of Heaven SoundFont plus MIDI, KAR and BIAB files and User Styles
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