Are music octaves and harmony universal?


i.e. – Would octaves even behave the same in a high-pressure ammonia-rich atmosphere? By extension would alien music necessarily sound harmonious to us if we encountered it?

In: 6

Yes. Going up an octave is done by doubling the frequency of the sound. There’s a lot of consonance there. Two higher pitched sound waves fit exactly into the lower pitched waves.

I suppose you might have a culture that prefers dissonance to consonance, but there is no question how consonant an octave is.

Octaves, fifths, fourths, thirds, the circle of fifths, these are all mathematically related, and math is universal.

Musical intervals are based on the ratio of two frequencies, for example an octave is a 2:1 ratio. Regardless of what those sound waves are traveling through, that ratio won’t change since the medium will affect them equally.

As far as universal harmony goes, it’s not entirely consistent across human cultures. Heck, even if you stick to western musical theory there’s a fair amount of variation. Though generally, small ratios (like 2:1, 3:2) are preferred to large ratios (like say 43:32). It’s not impossible that an alien would think about it the other way around though.

Now, for most people there is a bit of wiggle room, if the frequencies are close enough it’ll still sound alright. For example, in modern western music theory, only octaves have a perfect ratio and every other note is off by just a little bit, and it still generally sounds good.

Musical notes that sound consonant are universal.

An octave is a ratio of 2:1, so the peaks of the amplitude of each frequency will always line up perfectly. The medium does not matter, the ratio remains the same.

Sounds are physical in nature.

So a perfect fifth is the second most consonant ratio – that’s 3:2.

Half of an octave is the square root of 2 – 1.41/1. There’s no easy ratio there. As it happens, the resulting ratio is a tritone – quite dissonant.

Something to understand is that while pure musical ratios are universal, our western system of dividing an octave in to 12 equal ratios is not universal. It is a very good approximation that makes the most consonant ratios sound good enough to our ears, but it is a compromise (If you’re interested in this I can point you down a very interesting rabbit hole). If you’re vaguely curious as to how music may sound that isn’t composed in the 12EDO system we use in most of the world, look up Sevish – he makes microtonal music in many different scales. It’s very different, but he does a good job making music that still sounds musical, but is also rather more alien to what we’re used to. And one thing that his music can do that most of our music does not is have shifts in color that are outside of the norm of a simple key change. It’s really neat!

In other cultures they may use different scales and tuning systems… But the pentatonic major/minor scales are very nearly universal across music on earth. And I would be quite willing to bet that in alien cultures, they are probably quite common too.

When you create any wave, harmonics will also be produced. Harmonics are waves that have integer multiple frequencies of the fundamental wave. Sometimes subharmonics can be created, that have frequency of 1/n times the fundamental, where n is an integer, but these are less common, and of usually lower magnitude. Harmonics happen because of slight imperfections in our instruments, even the best most accurate wave generators will still produce some harmonic content, although it’s magnitude will be teeny tiny. The harmonic content of instruments is what gives them their own unique sound, timbre, tonal quality, etc etc.

An octave is a doubling of frequency. Which means a note an octave above the fundamental, exactly equals the frequency of the first harmonic. The reason chords and octaves sound good when combined is that most of the harmonic content of the various notes are the same (in the frequency domain) so you’re not producing a lot of extra frequency content. Otherwise, you would just have a bunch of noise at different frequencies, which becomes close to white noise. Think lots of guitar distortion, heavy metal, etc etc.

So yes, this would happen no matter the medium of propagation. It’s a universal property.