In Program playback vs. MS MediaPlayer
I've downloaded several "user submittied scores" and my own creations.
When you save a score as MIDI and play it back with Windows Media Player it sounds different than when played inside the MuseScore program.. ( Differing speeds ) usually slower than inside the program..
(Although the "Many Flutes" by the Martin guy sounded better in Media Player than in MuseScore.)
Comments
If the speeds are different, you probably have the tempo scaling factor in the Play window in MuseScore set to something other than 100%.
The sounds themselves will always be totally different, as MuseScore's sounds are produced by whatever SoundFont you happen to have installed in MuseScore, and WMP's sounds are produced by whatever MIDI device you have selected in Windows. Generally, the default SoundFont in Windows will sound somewhat better than the default MIDI device used in Windows, but you install better SoundFonts for Musescore very easily (see the corresponding section of the Handbook).