Can someone explain “four part” harmony and its difference or/and its relation to regular harmony? I’ve been searching the internet and can’t find any information that clearly answers my question towards the subject.
Any harmony is more than one voice, or instrument sounding simultaneously, producing different notes which blend melodiously together.
Four part harmony comes from four voices originally, the highest being two female voices - soprano and alto, under which comes tenor and bass. Each has its own line of music, which is followed, along with the others singing simultaneously. It's usually written out as soprano, stems up, alto stems down on treble clef, and tenor, stems up, bass stems down on the bass clef stave.
It doesn't have to be human voices - it can be instruments, each of which follows its own line of music.
"Harmony" is a generic term for the result of putting multiple sounds together at the same time. "Four part" harmony essentially means that there are four simultaneous tones involved. More specifically, "Four part" harmony derives from vocal music arranged for four voices: soprano, alto, tenor, bass.