Piano World Home Page Forums Our Most Popular Forums Adult Beginners Forum why C# over Db for major scales? music theory question.

I was reading some online music theory lesson and this came across. What is the reasoning and would it be wrong to use one over the other?

Along the same lines can anyone recomend any free online music theory lessons or a good music theory book?

I found this site useful:
http://www.dolmetsch.com/theoryintro.htm
As far as your question, I'll go out on a limb - typically, one will see sharps being used if the key signature contains sharps, and vice versa, of course. Could be wrong - just a guess.

HM

It doesn't matter which one you use. It's just an enharmonic change. The use of either a sharp or a flat depends on which one fits into that harmonic sequence.

The way my teacher described it is that it's a matter of spelling. For example, an 's' and a 'c' can have exactly the same sound. But the word is only spelled correctly with one or the other.

Likewise, for a given scale, the notes are spelled a certain way. The same way that you can double-flat a note. If you're double-flatting G, then the note is Gbb and not F.

Scales are the building blocks of harmony. One learns the C# Major scale to learn the notes used in C# Major harmony.

This, obviously, begs the question: Why use C# Major harmony instead of Db Major harmony?

The answer lies in the harmonic direction the entire section, movement or piece takes. It is rare for even a short section of a work to remain in a single harmonic key, and the keys to which the harmony migrates usually dictate which "spelling" of a scale is used in order to make the notation simpler as the harmony modulates. For example, if the harmony starts in C# Major and modulates to F# Major, the notation would involve placing naturals on the B's (C# Major = 7 sharps / F# Major = 6 sharps). However, if the harmony were to move to G# Major, one would need to double-sharp the F's (kind of ugly); if one started with Db Major and moved to Ab Major, one would only need to put a natural on the G's (Db Major = 5 flats / Ab Major = 4 flats).

Hope that makes sense.

whoa, i must have read that 4 times and its still confusing. but hopefully with some reading i will understand better. Thanks for taking the time to explain it though.

Let's see if I can use a really bad metaphor (don't think I'll have any problem with that!) to explain a little further.

If one were to stand in the middle of the intersection of two roads (Fast Rd. and Wide Rd., if you like), you wouldn't be able to say with certainty which road you were on. At that point you are on both roads equally. This is the situation with enharmonic equivalents: you can't say that there's any actual difference between them.

Now, say you want to travel down one of those roads away from the intersection, let's say down Fast Rd. Would it be easier to describe your starting point in the middle of the intersection as being on Fast Rd. or on Wide Rd. instead?

This kind of decision is based on where you may end up going, and folks that write music take this into consideration when putting the notes on paper. So, when the starting point is C#/Db, it's a matter of knowing whether you're going to be headed into keys with sharps in them or into keys with flats. Keeping the number of accidentals (i.e., notes not in the key signature) to a minimum is usually the goal. If the music will head off into sharp keys, start with a key containing sharps (C# in this instance); conversely, if headed into keys with flats, start with a key using flats (Db here).

I guess the point here is that (using the metaphor again) if you never leave the intersection, there's no difference between the two choices. It's when you move away from there that it becomes an issue.

I like the metaphor!

Yea, but what if Wide Street is a really REALLY really REALLY wide wide Wide-wide-wide street? Then no matter how far you went on Fast Street, you'd still be on Wide Street,too. (unless maybe you went REALLY really REALLY fast fast Fast-fast-fast.)


What do you think? I got possibilities at least as a drummer maybe? (I already KNOW how to deliver pizzas and steal!)

I just love this theory stuff! It just, oh I don't know,...wow, just exPANDS your mind so much, I guess. Jeepers.

I like the intersection metaphor. Thats a very good way to explain it.

Do the streets have to be perpendicular?

I like that metaphor, too! But, alas, I'm still confused . . .

Well, OK, that makes sense. But do all sharp keys have a corresponding flat key signature? If so, then you could start with a sharp key signature because you'll be using a sharp key signature later. But couldn't you also just change both key signatures to the corresponding flat key signature and write the piece that way?

Right? No?

Ugh.

In theory (no pun intended), all keys can be written in either sharps or flats, but many of the variants would require excessive respelling of notes just to work. For example, you could write a piece in E# Major, but doing so would require 4 double-sharps and three sharps (!), whereas F Major only requires one flat. Clearly, from a legibility standpoint, simpler is better. When the number of sharps or flats reaches 6, it's a wash (compare F# Major with 6 sharps against Gb Major with 6 flats); anything beyond six means there's a simpler way. But because of the desire to keep the score simpler, one might actually use a key of 7 sharps or flats if the direction of the piece moves into areas with fewer sharps or flats.

Changing the key signature is a sort of last resort, used when the harmony has veered so far afield from the original starting point as to create far too many accidentals. If a piece starts in Bb Major and wends its way into A Major, a change in key signature would be far better than putting naturals on all the B's and E's and sharps on all the F's, C's and G's. Even so, the composer (or editor) might not bother with a key signature change if the new key doesn't stick around very long.

Clearer?

No. In fact, if you want to create a visual map of how it might work, and give yourself nightmares at the same time, consider this:

The road map resembles Paris, after a fashion. There are 12 roundabout intersections, each having 11 roads leading to each of the other roundabouts. The spoke roads emanating from the roundabouts can intersect with each other at any angle.

Hey, you asked! :p Besides, shouldn't you be working on your cadences?

Stop this incessant whining about the French!

This whole discussion is sooooo neat. I love theory!

Thanks Matt. The metaphor makes it a lot more understandable.

I have been watching the exchange of ideas here on the side. Matt, I'd like to commend you for your patience in explaining those hard to understand stuff. I understood it better with your metaphor.

I'm a real real beginner and I'm learning a lot from you guys. I have just been taking lessons for about a year. A real rookie.

I know this is an old topic but I'm new to the forum and this is my first post.
Therefore I beg your indulgence and ask your forgiveness if I mess this up.

I asked my piano teacher the exact same question a while back. She explained that when you transpose to a key all the notes shift in that direction.
Going from C major to D major scale you are moving to the right of the keyboard therefore you end up with C sharp and F sharp not D flat and G flat although they are essentially the same keys.
Also she said some notes are self defined. If you type a B flat chord your thumb hits a B-flat. Calling it an A sharp note confuses the issue. This stuff is hard enough already!

My understanding of this (though simplified)is that the scale of what ever key you're playing in is alphabetically arranged so that you can't have , say a G and a Gb (has to beF#)...or B and B#(Has to be a B and C). Only one note name per scale, not just a good idea it's the law . Hope that makes some sense.