An approximative compression is able to extract that part of data which is responsible for the most important part of the expected result. That is, we accept some loss of picture or sound quality, in exchange of saving a lot of space. The most versatile techniques allow to choose the compression ratio, and therefore the balance between size and quality. It's remarkable that such compressions are possible, but it must be said that they involve advanced mathematical techniques, applied to specific types of data. MP3 is just one of these techniques, relevant to sound files.
Real audio is another one, which performs a higher compression but with a greater loss of quality.
Such techniques are also available for pictures, resulting in JPEG or GIF file formats, well known on the net. The compression is made on the WAV file recorded on the source configuration. The AudioHQ - Soundfont dialog box allows to load soundfonts into memory, up to a total size of 64 M b. A set of fonts with a patch for each of the instruments in the General MIDI mapping is called a sound bank . Obviously, the better are the patches, the larger they are, and thus the same for the bank itself.