What is a SoundFont?
A soundfont is a set of audio samples necessary in order to play a MIDI file or similar music formats. It's just like text and a text font. The MIDI format doesn't contain what audio is played, only the notes of the instruments, so a soundfont is necessary in order to play the audio.
It's technically possible for a software to synthesize notes from parameters that describe how sound waves should be generated, without requiring any audio samples. This is done with some chiptunes, for example. I assume that piano notes synthesized this artificial way don't sound the same way as using audio samples from a real piano, which is why soundfonts are still used.
Quotes
SoundFont2 (or SF2) is a widespread standard which allows encoding banks of wavetable-based sounds into a binary file. [...]
Both sample data and structure data is embedded in the same SF2 binary file. A single SF2 file can contain up to a maximum of 128 banks of 128 preset programs, for a total of 16384 presets in one SF2 file. The maximum number of layers, instruments, splits, and samples is not defined, and probably is only limited by the computer's memory.
https://csound.com/docs/manual/SiggenSample.html (accessed 2025-04-11)
I'm not familiar with how what these terms mean, exactly, but I do know that the MIDI format uses 7 bits to store which instrument is being played, which means there are 128 instruments in total, and it also uses 7 bits to store which note (do re mi fa sol la si). I assume "128 banks of 128 preset programs" refers to all possible notes of all possible instruments.
To fully exploit the capabilities of SynthFont you definitely need a good General Midi SoundFont. A GM SoundFont has presets (instruments) defined for all 128 melodic midi programs, plus at least one percussion set. Within this list you will find links both to GM SoundFonts and to SoundFonts with individual instruments.
https://www.synthfont.com/links_to_soundfonts.html (accessed 2025-04-11)
Surf the Web
- https://soundfonts.darkesword.com/ [accessed 2025-04-11]