Is there any popular music that belongs to multiple keys because they only use the notes that are shared between them?
Or, is there anything that doesn't belong to any key because it uses more notes than are allowed by any key?
There are probably one or two examples somewhere, but it's certainly not common.
Keys are like the rails that keep a train on the tracks. If you don't have them, or if they're too non-linear, you lose a sense of momentum that keeps untrained people listening.
Classical music meanders for a while and then stops at cadences, which reinforce the key. It's like a train ride with stations. A key change switches the ride to a different track, but you always get a series of pauses and restarts.
Modern music uses ambiguous chord sequences - usually four chords - that repeat over and over but never come to a climax or a pause. The chords are ambiguous because they fit with a couple of keys - usually related major and minor, or perhaps a mode - but without the stops there's no clear sense which applies.
So you get continuous but repetitive motion on a single track without the stops. It's like being stuck on a loop and going through the same station over and over without stopping.
Sometimes the scenery changes between the verse and the chorus/drop/whatever. But without the clear key stops you can't get off.
I don't agree with that.
A key is not just a collection of allowed notes, there is a kindof frequency distribution to them too, so that the tonic is either the most used or the most implied. The fifth is often the second-most-used. Its sortof like a key has a 'center of gravity' in the tonic note. Either it will be used a lot or alluded to a lot.
So a chord sequence might technically fit into different keys but usually there is an implied tonic and that 'tells' you what key you are in.
So within a (well constructed) chord sequence in modern pop you can still have suspense and resolutions and so on. Kindof the same as cadence but done in a different way.
And the trick to a good key change is to subtely shift the 'weight' in the direction of the new key just before you make the change.
It's not even "modern," people still sit around arguing about which key certain beatles songs are in, when again "more than one" is a more useful explanation.
And I mean I know you know this but for other readers: music theory isn't like a math formula where song goes in, answers come out. It's a practical framework and a vocabulary for communicating about music, and evaluation of a successful analysis has to be based on the usefulness of the evaluation. There can be multiple "correct" analyses of the same piece of music, with different usefulness to different people at different times.
Pop music has influences from outside the mainstream european music traditions, and so certain assumptions that almost always make sense within those traditions (eg songs have a key, with a tonic) will lead you to goofy places sometimes.
Not exactly, take for example the Cmaj scale. You can write different melodies that "gravitate" around one of the 7 notes and that effect makes up for a particular mode of the scale of C. Even if the notes are exactly the same you can easily hear the different flavor of each mode.
The easiest way to hear the modes is to play continuously the Cmaj scale against a C drone (a long note), but each time starting from a different grade of the scale of Cmaj. Same notes, different feelings. It's unclear to me (and I think controversial even among musicians) if you should use the mode name as a qualifier for the key and usually people just say that a song is in the key of $note, but you can definitely hear the difference. In particular, it is (was?) common to modulate to the relative minor/major key to highlight a section of a song (e.g.: key changes from Cmaj to Amin, same notes).
> Is there any popular music that belongs to multiple keys because they only use the notes that are shared between them?
It's very common in jazz, a classic example: Giant steps by Coltrane. The song continuously modulates in major thirds and loops around three keys.
> Or, is there anything that doesn't belong to any key because it uses more notes than are allowed by any key?
Look up "serialism" and "atonal music".
A key is not just a collection of allowed notes, there is a kindof frequency distribution to them too, so that the tonic is either the most used or the most implied. The fifth is often the second-most-used. Its sortof like a key has a 'center of gravity' in the tonic note. Either it will be used a lot or alluded to a lot by the other notes.
Is there any popular music that belongs to multiple keys because they only use the notes that are shared between them?
Sortof - the notes might technically be part of a few different keys - but usually there is an 'implied center of gravity' pointing to a tonic note and that tells you what key you are actually in. But if you make it ambiguous for a few bars it can be a useful musical effect, sorotf suspense. And then you resolve to one or the other possible candidates and it sounds cool. But if you do it for too long it sounds muddy.
A good key change is sortof like that, you hover in a space that could be either key for a bit then resolve to something specific.
Or, is there anything that doesn't belong to any key because it uses more notes than are allowed by any key?
Jazz goes all over the place. Accidentals, key changes. An accidental is like a single note that isn't 'in' the key. Perhaps like a one note key change. The keys are still part of it but its more adventurous.
If you completely ignore key altogether its polytonal and it sounds kindof annoying.
Or people invent their own ones, e.g. Aleksi Perälä and the Colundi Sequence https://thequietus.com/articles/20493-aleksi-perl-perala-col...
Althought there's a big argument as to whether western keys are all just conditioning or something intrinsic. e.g. Does Major sound 'happy' and Minor sound 'sad' to all humans? Octaves are pretty universal in human music but after that it gets complicated. I think there's some good pointers to how overtones in in inner ear correspond to frequency ratios which correspond to classic intervals such as the third or fifth. And then how best to construct a scale that squeezes in the most useful thirds and fifths and so on. If you follow that exercise then the white keys/black keys on a piano start to look quite optimal. BUT social conditioning, anthropology and so on so maybe not.
It's all patterns, and getting the balance between repetition and change.
It uses all the notes on the chromatic scale, so it doesn't "fit" into a specific key. (But it's still considered to be in a specific key. The notes outside that key are the exception not the rule.)