Different MIDI players have different sounds. The Buzzwood MIDI Voice Tester provides an easy way to preview each of them with an individual demo sequence for each voice.
The locations of the 128 voices are slightly different form the GM standard for convenience. 'Fiddle' is now next to 'Violin' and Tympani is now in the Percussion section. Voices formerly in the GM 'Ethnic' category are now in their respective instrument groups.
Click your way around the list and you may discover some new timbres, tricks and tones. Then try it on a different MIDI player or device. The voices may sound strikingly different.