Well... it's not actually that mysterious 
BACK-ON is read as 'baku-on' and the kanji is 爆音, which is the sound of an explosion or an explosive sound.
Never thought about this before, but this is the Japanese version of an Onomatopoeia?

BACK-ON is read as 'baku-on' and the kanji is 爆音, which is the sound of an explosion or an explosive sound.
Never thought about this before, but this is the Japanese version of an Onomatopoeia?