All the MIDI samples here are patched for General Midi . MIDI means Musical Instrument Digital Interface. A computer can be MIDI equipped too, and through software, full orchestration is possible. MIDI playback must always be through a synthesizer. To get really good or realistic sounds you need the best synth available.
Digital audio is a numeric representation of sound.
CD's work on a particular digital audio format, while computer audio files use various others. Each micro-analysis of the sound is written into a binary numeric word, or byte. Obviously, the more often the sound is analysed, the more accurate, or detailed the picture will be. The sample size is how many digits, or 'bits' are compiled into each analysis. Again, the more the merrier, as this results in a more detailed description of the sound.