Identifying chords

[outin]

So I'm going to to give in and study the chords a little. But only when it's directly applicable on my music

So I wonder if someone could help with this question without quoting pages of music theory (if this is necessary then I'll just have to read the books myself):
How do you identify chords in sheet music? Do you have to know something about the rules of composition (which chords are used in certain keys)? Some are of course easy to spot, but if the chord is inversed and maybe some notes are omissed, then how do you find out which it is?

[nystul]

Basically you just have to figure out which notes are part of the chord and then add them all up and see what you've got.  Sometimes there isn't a clear answer and you have to consider the context of the chord within the piece, which requires some degree of knowledge and experience.

Let's use the Chopin Am posth. waltz as an example since I know you have the music to it.  OK, a lot of waltzes have this "oom pah pah" pattern where you have a bass note on count one and then harmony notes in the tenor on 2 and 3.  So the chords may be a lot easier to figure out in a piece like this than say a fugue.  But it is good to start with something easy.

First measure:  Bass note is A.  Tenor range is ACE.  Melody goes ABCC.  Pretty obviously this measure is A minor.  We can call the B in the melody a "passing tone"... it leads from the A to the C but isn't part of the chord.

Measure 2: Bass is D.  Tenor has ADF.  Melody goes DEF.  OK, so it is D minor.  The E in the melody is again a passing tone between the D and F.  Notice by writing the tenor as ADF, he keeps it right in the middle C range (barely moved from the ACE of the previous chord).  If he wrote it DFA, he'd have to move it way up or down out of the intended range.  Technically we don't consider this an inverted chord, because the bass note D is still the root of the chord.

Measure 3: Bass is G.  Tenor has GBF.  Melody goes BCDAGF.  It's a G7 chord (GBDF).  He did not write the D in the tenor, but it shows up in the melody.  Even if there were no D, GBF would be considered a G7 chord.  The C in the melody is a passing tone just like in the previous measures.  The A in the melody could throw us off, if the left hand didn't make things so obvious.  But it is just leading to the next chord note G.

Measure 4: Bass is C.  Tenor has GCE.  Melody goes (EF)ED#E.  This is a C major chord.  The melody is essentially just E with some decoration.  Again he inverts the notes in the tenor to keep it right there in the middle range, but keeps the root note in the bass on count one.  If you play just the tenor notes of these 4 measures, you will see your hand barely moves even though it is 4 different chords. 

So the first four measures each had one chord and we have a progression like this: Am, Dm, G7, C.  As I glance at a sheet, it appears that this 4 measure chord progression is repeated 3 more times to finish the first segment of the piece.  I was thinking this is very lazy of Chopin, but then I remembered he was dead when he wrote this!  But there are a few interesting things to note about these chords.  One is that they all move by fifths.  A is the fifth of D, D is the fifth of G, and G is the fifth of C.  Only then he breaks out of the cycle to go back to A and start over again.  The other thing is it creates a kind of question... are we in A minor is or is this C major?  To me it is like a little mood change every 2 measures. 

Well I don't know if this helps any but hopefully it might be of some use.

[outin]

Wonderful, exactly what I needed! Thanks for taking all that trouble to break it down to such a detailed and simple explanation! 


I didn't actually think about using the right hand as a clue...

Measure 3: Bass is G.  Tenor has GBF.  Melody goes BCDAGF.  It's a G7 chord (GBDF).  He did not write the D in the tenor, but it shows up in the melody.  Even if there were no D, GBF would be considered a G7 chord.  The C in the melody is a passing tone just like in the previous measures.  The A in the melody could throw us off, if the left hand didn't make things so obvious.  But it is just leading to the next chord note G.

The third measure was what got me stuck last night. I figured it must be a 7th chord but wasn't sure. The chord charts confuse me because there are so many different kinds of chords...

So the first four measures each had one chord and we have a progression like this: Am, Dm, G7, C.  As I glance at a sheet, it appears that this 4 measure chord progression is repeated 3 more times to finish the first segment of the piece.  I was thinking this is very lazy of Chopin, but then I remembered he was dead when he wrote this! 

Exactly, but I'm lucky that he was, because nothing he actually finished while he was alive ended up this easy to play...

  The other thing is it creates a kind of question... are we in A minor is or is this C major?  To me it is like a little mood change every 2 measures. 

I generally can't tell what key music is in if I don't see the sheet (and sometimes even then). Luckily most composers were kind enough to write it down for us.

Well I don't know if this helps any but hopefully it might be of some use.

It helped a lot, thank you again!

[outin]

Measure 2:

... If he wrote it DFA, he'd have to move it way up or down out of the intended range.  Technically we don't consider this an inverted chord, because the bass note D is still the root of the chord.

Could you explain this a bit more... What then would be an inverted chord? I thought the chord is always inverted if the lowest note is something else than the root note?

[nystul]

Could you explain this a bit more... What then would be an inverted chord? I thought the chord is always inverted if the lowest note is something else than the root note?

If you just consider that group ADF, it is an inverted chord.  But in terms of the big picture, the D on count one is really the bass note of the harmony.

[outin]

If you just consider that group ADF, it is an inverted chord.  But in terms of the big picture, the D on count one is really the bass note of the harmony.

OK, thanks!