How come music using the same chord progression can sound so different? A lot of Japanese pop songs use 4 popular chord progressions, but how come these songs can come in such a large variety and sound almost nothing alike? What are the factors that allows songs using the same chord progressions to sound so different from each others?
Music has many, many elements beyond chord changes. Here are a few, any and all of which can be combined to create unique songs.
- Different melodies
- Different meters
- Different rhythms
- Different tempos
- Chords lasting differing amounts of time
- Different chord voicings and patterns of execution (e.g., block chords versus arpeggiations)
- Different (combinations of) instruments
- Different singers with different vocal qualities
- Different musical forms (e.g., verse/chorus; AABA song form)
- Different lyrics
I would just like to add on Aaron's answer, that at least within the 12 note tonality convention that I'm used to and I believe most modern music stems from that there is also timbre of the instruments involved, these combine in different ways manipulating the audible frequency spectrum to generate new sounds.
This is definitely included in the categories mentioned in the answer above, but... synthesized sounds. So much music today is so processed and altered electronically (not necessarily a bad thing), and these really alter the timbre of their notes, and, consequently, the "feel" of harmonies. The synth layer can be comprised of some pretty simple (but elegant) chords. But the timbre of the synth voice with its resulting harmonies of the "cadences" you choose, especially sustained or extended chords, can create a really unique sound.