determining chords in any key

In Western music, the 1, 4, and 5 will always be natural:

Major - 1,2,3,4,5,6,7,8
Natural minor - 1,2,b3,4,5,b6,b7,8
Harmonic minor - 1,2,b3,4,5,b6,7,8
Melodic minor - 1,2,b3,4,5,6,7,8

Other scales can contain altered 4ths or 5ths, and you harmonize them just like you do major scales... but what they're referring to is the basic major and minor keys.

I think he means Bb, Eb, F in the key of Bb major as compared to C, F, G in C major. Yes, it's perfectly fine for the I, IV, and/or V to be either sharp or flat, you just can't have both sharps and flats in the SAME key.

you just can't have both sharps and flats in the SAME key.
Of course you can. D harmonic minor:

D-E-F-G-A-Bb-C#-D

ooh didnt think of that.

You got me. I meant MAJOR key, but just forgot to type it

*tries to beat NoteBoat at thinking of a key but realises its impossible, to think of a key AND beat NoteBoat at something*

lol.

the only things i can think of is sharps and double sharps, and a double flat scale, which isnt really used. unless modulating up a diminished fifth from a flat scale, i think i have that right, but im not entirely myself at the moment (:smoke: :smoke: :smoke: ) lol.

anyway music theory rocks!!! (and no im not being sarcastic).

i saw a board in my school and i saw it said B half diminished (half diminished sign, i cant be bothered going to character map to get it and i saw it had B D F, and was saying how it wasnt true, and found someone who agrees with me and then i found someone who knew the same (roughly) about theory, as me, so i have 4 people i can talk to physically about theory, 2 teachers, my guitar tutor and this guy. I dont know where this story came from but i just feel like typing at the moment, my last 3 posts crashed before i could post them so i would be surprised if when i hit the "Submit" button, it goes through lol.

B-D-F makes a plain old B diminished, Alex. A half diminished chord is 1-b3-b5-b7, also commonly called a m7b5 chord.... it's called half diminished because the top note is only halfway towards forming a diminished seventh, which is 1-b3-b5-bb7 (three consecutive minor third intervals).

In some theory texts there's a distinction made between a m7b5 and a half diminished, with a m7b5 resolving to a root a fifth lower, and the half diminished resolving to a chord with any other root... but most of the texts I've seen in the past 10 years or so just go with m7b5.

I read in a book, ( guitar by ear) you can figure out the Major Chords
1, IV, V for any key by going 5 and 2, if the song is in the key of G you could use the low E string go to the 3rd fret which is G then go up 5 Frets and you have C then go up 2 Frets more and you have D,. G, C, D this method works in all keys, so remember 5 and 2 if you forget the Major Chords to any key.

:D

Okay okay, so theory is my weak point, NoteBoat: Please make my head explode with an abundance of knowledge here.
Of course you can. D harmonic minor:

D-E-F-G-A-Bb-C#-D

When I saw this, I thought you were just being a smarta$$, but no one else seems to be reacting to it that way, so I'm now coming out to express my ignorance and ask why you didn't just write it like either:

D-E-F-G-A-A#-C#-D

or

D-E-F-G-A-Bb-Db-D

I don't recall all of my piano training, but I don't recall ever starting a song where there was both a flat and a sharp in the key signature, nor do I recall any sort of exceptions to the order of sharps or flats.

Enlighten me.

I read in a book, ( guitar by ear) you can figure out the Major Chords 1, IV, V for any key by going 5 and 2, if the song is in the key of G you could use the low E string go to the 3rd fret which is G then go up 5 Frets and you have C then go up 2 Frets more and you have D,. G, C, D this method works in all keys, so remember 5 and 2 if you forget the Major Chords to any key.

Again, I'm no theory wiz (that's part of why I'm here) but I know that there are closer versions of those intervals. The 5th is the same note you would use to create a "5 chord" or "Power Chord" with, while the fourth is generally the note on the same fret, one string higher in pitch. Of course, everything has to be shifted for the 4th to 5th string difference, which is a major 3rd as opposed to the perfect 4th between all other pairs of consecutive strings.

D-E-F-G-A-A#-C#-D

or

D-E-F-G-A-Bb-Db-D

You never have the same note name twice in the same key (here you have A & A# and Db & D). This is because a key is built from intervals. An interval has both value and quality. Any kind of A (Abb, Ab, A, A#, Ax) to any kind of B (Bbb, Bb, B, B#, Bx) will always be a 2nd interval, because there are two note names involved. Any kind of A to any kind of G will always be a 7th (7 note names). A to A# is a 0 interval, which cannot occur in a key. The quality of an interval (diminished, minor, perfect, major or augmented) will affect the pitch of the note (Abb is a semitone lower than Ab, which is a semitone lower than A, which is a semitone lower than A#, which is a semitone lower than Ax), but not the interval

Even though they are enharmonic (which is why I used "note name") you would always have Bb & C#.

Any kind of A (Abb, Ab, A, A#, Ax) to any kind of B (Bbb, Bb, B, B#, Bx) will always be a 2nd interval.

Wow, this really doesn't click with me, you're saying F# to B is the same interval as F# to Bb? Because I would have said that the former was a perfect 4th, while the latter was a major 3rd. In this case, what interval are they both actually?

A to A# is a 0 interval

Um... it's still a half step... When I think 0 interval, that's code for unison in my brain. What'd I miss?

I'm catching on to the note name thing here... slowly, but you COULD play these notes consecutively in the same key, you would just have to call them something else?

but you COULD play these notes consecutively in the same key, you would just have to call them something else

You've got it.

The interval is determined by the number of letters in the sequence - A, B, C, D, E is a 5th, because there are 5 note names (letters) in the sequence. A to B is a 2nd because there are two note names. A to E# is still a 5th because there are still 5 note names in the sequence (A, B, C, D & E), even though E# is the same pitch as F. However, calling the note F, instead of E#, would give you a 6th (A, B, C, D, E & F), not a 5th.

See if this helps

Hiya Undercat. Greybeard's done an admirable job... I'll just expand on it a little bit.

Theory is a means of categorizing music so it can be analyzed. It's an important part of a complete music education, but it's not music... it's just how to look at music in an efficient and reproduceable way. The simplest way to understand the 'why' behind theory issues is to follow the historic trail.

If we start out with the sound of a scale, like that D harmonic minor, it doesn't matter at all what you call it - it'll still sound the same. The initial trouble is... it sounds just like a C harmonic minor scale does, if you don't have a reference tone. So the very first thing we have to figure out is a reference note, and we'll call that A (as in A=440). That way two musicians can play the same piece and not be out of tune. Other letters through G followed (there weren't any sharps or flats then)

The next problem was how to write something down so we could reproduce it. Early efforts at notation looked something like this:

- -
- -
- -
- -


with notes being represented in relation to each other. When there's a leap between two marks, it was hard to tell just how big a leap we were talking about, so the next thing was adding some lines - four to begin with - to show how big the spaces between notes were.

Next, people started to alter notes. Bb came first, followed by other flats and sharps. Originally, these were noted next to each note - at this point we're still OK with noting A and A# in the same key. As music became more complex, it got harder to read... too many accidentals... so eventually they were grouped together in a key signature, and only notes that departed from the key signature were noted with accidentals.

That's the point where scale spellings need standardization. In the case of D harmonic minor (relative to F major), every B note will be flatted by the key signature. Looking at the notes themselves, that means we can write the harmonic minor scale like this:

D-E-F-G-A-B-C#-D (the B already flatted by the key signature), or like this:

D-E-F-G-A-A#-C#-D - the alternate method you've proposed.

It doesn't seem like a big difference when you just look at a scale. Look at a melody, and it's huge - I'll use N to indicate the natural sign, and do the scale in thirds:

D-F-E-G-F-A-G-B-A-C#-B-D-C#-E-D

D-F-E-G-F-A-G-A#-AN-C#-A#-D-C#-E-D

The first one has two accidentals, the second has five. It gets really cluttered, really fast. If there's a lot of shifting between A and A#, you quickly reach a point where the key signature isn't doing you any good at all.

From that came the convention that the seven notes of any major or minor scale must have seven different letter names.

Having named the notes, intervals follow... as Greybeard has pointed out, an augmened unison (A-A#) is theoretically different from a minor second (A-Bb), even though they sound the same. Musically there's no difference... but theoretically it's very important, because of the way they'll be written and read.