Wikipedia:Reference desk/Archives/Entertainment/2020 April 4

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April 4

D-flat major or C-sharp major

Play the following melody in 3/4 time (all notes are quarter notes unless noted otherwise):

A♭-F-E♭-D♭-E♭-F-A♭-F-E♭-D♭-E♭(8th)-F(8th)-E♭(8th)-F(8th)-A♭-F-A♭-B♭-F-B♭-A♭-F-E♭-D♭(dotted half)

Now listen to the sound and hide the notation so you won't be able to know what key it is in. Does it sound like it's in D♭ major or C♯ major?? It clearly sounds like it's in D♭ major because we are familiar with one of the notes as the white key F, and all the other notes sound like appropriate intervals from F.

Now try this, though (again in 3/4 time and all notes are quarter notes unless noted otherwise):

E-C♯-B-A-B-C♯-E-C♯-B-A-B(8th)-C♯(8th)-B(8th)-C♯(8th)-E-C♯-E-F♯-C♯-F♯-E-C♯-B-A(dotted half)

and then, continue as:

E-C♯-B-A-B-C♯-E-C♯-B-A-B(8th)-C♯(8th)-B(8th)-C♯(8th)-E-C♯-E-F♯-C♯-F♯-G♯-E♯-D♯-C♯

and then continue with the same above melody that I asked you to play first. Once again, hide the notation and listen to the sound. Because we've come up from an F♯ before the piece modulates, the immediately following note sounds like a G♯ and not an A♭, so it now sounds like we're in C♯ major. Is it sometimes easy to make a melody sound more like it's in C♯ major than in D♭ major?? Georgia guy (talk) 23:22, 4 April 2020 (UTC)

In what way does C♯ major sound different from D♭ major? --jpgordon^{𝄢𝄆 𝄐𝄇} 23:36, 4 April 2020 (UTC)

C♯ is a chromatic semitone above C. D♭ is a diatonic semitone above C. Georgia guy (talk) 23:42, 4 April 2020 (UTC)

Only if you aren't in equal temperament, and if you're using a just intonation tuning system (who does that?) it is likely that most listeners wouldn't be able to tell the difference in a few cents anyways. If you are using equal temperament, for example playing the tune on a standard fretted stringed instrument or keyboard, or really any instrument since 99% of musicians are ear trained in equal temperament anyways, the two keys are entirely identical, the only practical difference would be which key is easier to notate so that your musicians can recreate your intended music easiest. The key you assign a musical piece to is mostly arbitrary from a sonic perspective, all that matters is which key makes the most sense from a notation and reading perspective; choosing a key is a way to communicate things to the players so they can easily take your music from the page, and both play it easily and also conceptualize and contextualize what it is doing most easily. The whole "chromatic semitone vs. diatonic semitone" is basically music wonkery of the most pedantic kind; my wife is a life-long musician and plays multiple instruments across a wide variety of instrument families, and if you mentioned such matters to her, you'd get nothing but blank stares in return. It's the sort of thing which may be true (for certain values of true, again, if you are in equal temperament, it actually isn't true) but which is simultaneously useless knowledge for most musicians. So the answer to "which key" basically boils down to "what will make the musicians play it correctly". There is no universally correct answer. Lots of really common music isn't even clearly in one key or another (for example, "is Sweet Home Alabama in G-Major or D-Mixolydian" is such a common debate that it's almost a meme at this point, and the correct answer is "Yes, Both, Neither, and Does it Even Matter"). Remember, this stuff is not based on "baked into the universe mathematical laws", it's a human created system designed to improve communication between composer and musician. --Jayron32 18:09, 6 April 2020 (UTC)

The context will provide the difference: if we got here from C-sharp minor, it's probably C-sharp major, and if we got here from A-flat major, it's probably D-flat major. They sound the same, but they have different meanings in the tonal system (enharmonics are basically musical homophones); that's all the difference really is in equal temperament (it's just like the difference between an augmented sixth and a minor seventh; you cannot hear it, but the interval has the potential to be both, and this ambiguity can be used to change key). The notation may also make it easier to read for the musician, or have some sort of psychological effect or symbolic affective meaning, which could make a little bit of difference in the sound for an instrument like the violin which doesn't have the pitches already given to you like on the piano, but that's about it.

So, in your example (Edvard Grieg's Morning Mood), since we started in A major, yes, logically we have modulated to the mediant, which is C-sharp major (not D-flat major, which has a different meaning). If we kept modulating sharpwards, though, we would probably make some enharmonic change for reasons of practicality. Logically speaking, the first movement of Beethoven's Appassionata really goes from F minor round the circle of fifths twice flatward, and arrives back at A-quadruple-flat minor for the start of the recapitulation. But, of course, Beethoven writes the enharmonic changes that make it return to F minor instead as it should. Double sharp (talk) 16:52, 7 April 2020 (UTC)