I was recently thinking about how different cultures use different musical scales, yet the octave is always the same. An octave is basically when one note has a frequency that is double the frequency of the other note. So if a note has a frequency of 120 Hz, the octave up would have a frequency of 240 Hz. That definition is necessarily the same in every culture. But how you divide up the octave widely differs from culture to culture, and what “sounds good” with regard to combinations of notes also differs. For instance, Western and Middle Eastern music use two different scales (they divide the octave differently), and they also have two very different ideas about what intervals sound good. It is interesting how music can vary so much from culture to culture, but the octave will always mean the same thing. Some cultures might not consider the octave to sound good, but the octave is still always there. No matter what meaning people project onto the sounds, an octave will always exist. It is interesting how science is able to break the barriers of culture like that.