Is it like the visible spectrum and we just can’t physically hear anything else?
What determines the dividing line between each note?
I know this is more than one question but I just don’t understand the science behind music
In: Physics
Are we forgetting sharps and flats?
Most Western music uses 7 notes in a scale, with 12 total notes (notes outside of a key are called accidentals), but there are plenty of alternative tunings like 15 notes in an octave (the range from a note to the next note with the same name, like A to A) or 17 or 23 or….. any number really. 12 is just the most common
We can definitely hear other pitches, music using other tuning systems is called “microtonal” music and there’s plenty of it on YouTube
Western music has 12 notes between A and the next A. But music from other cultures use more. People familiar with that music will have an easier time hearing each note accurately but those of us not used to it would struggle, or hear some tones as “out of tune”, not realizing they are their own distinct pitches.
With sound you have lots of harmonics. Basically if you generate a sound wave it will usually also generate a wave double the frequency, and three times the frequency, and four times the frequency, etc. So we have learned to perceive these sounds as the same, so we name them the same. If you start with an A and double the frequency, you still have an A, just at a higher pitch. So the A-G notes just repeats as you get higher and higher in pitch.
As for the specific notes they are the sound waves which fit well together because they share harmonics. To start with A and E have a frequency ratio of 3:2. This means that the third harmonics of A is the same as the second harmonic of E. This is called a perfect fifth. We also use the minor third interval of 6:5 which in the case of A is a C. We can also go down a fifth and a third to get D and F. I can not remember the B and G intervals but it uses similar concepts of matching harmonics.
This gets us the 7 notes that sound good together and are the only notes you need to write a song. Any notes not using these specific 7 frequencies are probably not going to sound good. But you do not have to use these specific 7 notes. If you do the same harmonics calculations but instead of starting with A you start with C you get C,D,F and G from your A scale. But if you go 6:5 up from C you get a note that is higher then E but lower then F. We call this Eb or F#. Similarly you get Ab and Bb. If you go through all base notes this way you actually get 12 notes, not 7.
But there is more. Instead of using a ratio of 6:5 for the third, which sounds kind of somber, we can use 5:4. This is called a major third and sound more happy. You go through the same calculations of the ratios and you end up with the exact 12 notes. And if you start with C you end up with the original A-G notes that is used for A-minor.
This is the basic music theory used in western music. There are an infinite amount of frequencies of sound, it is just that we have found out that these sets of 7 notes out of 12 sounds best together as they have a lot of harmonics. Other music styles use different notes. This is why music from for example the Middle East or China sounds so different, they literally use different notes. And even things like Lo-Fi deliberately use other notes then those on the western music scale to sound different.
There’s a few things behind it.
First, music notes are waves with a particular frequency. So any note can be translated to the number of waves per second. For example, one note might be 440 waves per second.
Second is that if the number of waves per second between two notes are multiples of each other, all the peaks and valleys of the waves line up and they sort of sound the same. So a wave that was 220 waves per second and a note that was 880 waves per second would all line up with the 440 waves per second earlier. We consider those to be the same note on a different octave.
Third is that some combinations of waves sound pleasant to us while others sound grating, like nails on a chalkboard. It’s all based on the ratios between the frequencies of the notes.
And that leads to the way we divide up notes for music- each doubling of notes is considered the same note just in a different octave. The standard tuning most places use these days is that A=440 (but also A=220 and A=880 since it’s doublings) but the ratio is more important than the exact number, and in the past some places might have tuned A=435 or A=450. In between each octave is divided into twelve notes, which gives us a good compromise with having plenty of choices for soothing ratios between notes without being too complicated for musicians to play.
Because of the way the ratios work, we only typically play seven of the twelve notes at a time so those seven main notes are always labeled A-G, but sometimes at the start of a piece it may say “unless we say otherwise, play all the Fs a step up” or “unless we say otherwise, play all the Es and Bs a step down” if those combinations will produce the right ratios.
As far as how the in-between steps are chosen, there’s a couple ways to do it. The “best” way to do it from a sound perspective is to start with a base note (like A=440) and calculate all the other notes using the ratios from there. But that would require you to change the tuning of the notes for different songs, so for instruments like pianos, they’re usually spaced evenly apart (by logarithm, not evenly linearly because of the way hearing works) which keeps the ratios close enough that they still sound good even though they’re a little bit off from the perfect ratios.
It all depends on the culture that invented that system. A-G was invented by some guy who visualized it as the whole group, divided into 3rds, and those sections divided into halfs.
A super-short answer is that there are actually quite a few tuning systems used in the world, presently and historically. The system used most in western music (and the one you’re most likely familiar with) is called 12-tone equal temperament. https://en.wikipedia.org/wiki/Musical_tuning?wprov=sfti1
Sound waves can exist at pretty much any frequency or pitch (humans can hear frequencies between 20 to 20000 hertz, assuming no hearing loss), but how we choose to divide up those frequencies is dependent on historical, cultural, linguistic, and social factors.
Think about it like measuring distance. The distance between where I am sitting and, for example, my bedroom window can be measured in inches, centimeters, cubits, light years, or any other unit of measurement you can think of, but the absolute distance is the same.
People who grew up listening to mostly western music will typically find the 12-tone equal temperament tuning to be the one that sounds “right”, but that’s only because of their culturally-shaped expectations. If you grew up listening to, say, traditional gamelan music with its five-tone tuning system, western classical music might sound very odd and even “out of tune” to you.
Where I came from we actually call the notes
do – re – mi – fa – sol – la – si
But my knowledge ends here.
Thank you for coming my TEDx talk.
The visible spectrum was increased by Newton from five to seven, adding orange and indigo, to fit the notes of a scale.
This tuning system just kinda stuck and became the default but there absolutely can be others, a trained ear can distinguish two notes as having a different pitch if they are just 5 cents apart (in comparison the distance between A and B is 200 cents). The notes arent chosen completely arbitrarely though, they originate from a system utilising simple mathematical ratios which sound the most harmonious to us.
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