For instance if you are already registered for unlimited Play, order the second half of the code, and paste it after the first half. It specifies the instrument, note to play, and exact timings for all the notes. What it generates is somewhat akin to a score , but with exact microsecond timings of the notes, and exact specification of the pitch, and volume for each note. So what you hear will depend on how your pc plays back that 'score' . Modern high quality soundcards have actual samples of musicians playing a single note, say, on a Stradivarius violin.
Older ones approximate the sound of a violin, or other instruments, as best they can.
So you might be interested in downloading the Yamaha software synthesizer as well. It's available on 90 day trial, and is only 15 if you decide to buy it. It's also an easy way to get an alternative play back for MIDI even if you have a fairly good soundcard. There are many other software synthesizers available. There is a fraction of a second delay before the start of playback when using a software synthesizer.