I have been intrigued by this recently during piano lessons I realised that a lot of the melody I played in particular pieces was simply harmonised by single notes on my left hand. Having read Ellsa's request to look at this I thought it may be a good idea to start a new thread on these matters.

Can anyone enlighten us here?

In music theory, there are a few chords that are most often used to harmonize melody notes, ie, I, IV, V chords.

For examle: In the key of C, you will find that C maj chord, along with F maj chord and G maj chord harmonize well with any melody note that belongs to the key of C.
Sometimes, none of these three chords can harmonize the melody notes; ii min chord, vi min chord, or vii dim chord can be used to harmonize the melody notes.

Often, if you harmonize the melody note with the left hand chord, you can play just the bass note (single note) of the chord (or root and fifth).

If one likes to make the harmony sounds more interesting, one can try chord substitution or different voicing (closed or open, etc) to experiment with.

I notice this is a rather broad topic, the answer may not be complete. I welcome other comments!

Yoke Wong

http://www.playpiano.com/pianovideos.htm

Duanne Shinn offers a nice video demonstrating this technique using the song 'Silent Night' - it is free!

One common way to harmonize the melody is to add 2 more chord tones below the melody note you wish to harmonize. You will need to know the chord progression of the piece.Check out Pg 4 of the lesson download.: http://www.sendspace.com/file/05wxk8
Notice that the harmony notes are added on the strong parts of the bar beat 1 and 3. It helps outline the chord progression.

This rosetta stone, some don't like the word cheat sheet has helped me in the past.

Match the melody note with a chord that has that melody note in it's makeup. For example:

Degree of the scale - think of using one of these chords.
1 try the I, IV, vi or ii7 For example C note, then C chord (CEG), F (FAC), Am (ACE)or Dm7 (DFAC)would harmonize.
2 (D) try the V (GBD), ii7 (DFAC) or iii7 (EGBD)
3 try the I, vi or iii.
4 try the IV, ii or V7
5 try the V, I or iii
6 try the IV, ii or vi
7 try the V7 or iii.
Relying on this you could have a chord for every melody note - that is not a good idea. When the melody moves away from notes used in the old chord your ear will alert you something needs to change, i.e. it is time to find a chord that will fit (harmonize)with the new melody notes.

This little chart has helped me flesh out a progression. Like Yoke said the I IV V is a safe place to start then move to the minor chords in the key --- one of them will harmonize.

As to just one left hand note[/b], looking at this chart the Root seems to do this, i.e. C melody, C chord harmonizes so just use root C. D melody, Dm chord harmonizes again use D root, E melody, Em chord use E. The B did not follow this logic, however diminished seldom do. Not near a keyboard, but, I think I'm safe here.

{Edit} Would't this just be a hugh octive

When applying these principles do I assume that you only need to change the chord when the melody changes on certain beats?

Surely, you cannot play a block chord under each and every melody note!

You could play a chord for every note. That is how you play lockedhand style. That download is here: http://www.sendspace.com/file/llrtgs

I once had a teacher who made me play a 4 note chord on every down beat and octaves on any note off the beat, every song for 1.5 years. Stride the LH and you will sound like you are playing Hotel Style. That is not how I would recommend you play every song but I sure learned my chords and I can harmonize a melody like I'm riding a bike.

Pete, are these pdf extracts part of a book worth getting hold off??

Most of the pdf's are from the book I wrote. Some are just because I can not hang it up after a hard day teaching.I hope they are useful and explain things in detail.
I keep seeing questions that deserve a good answer on the forum. If you want more info please send me a PM.- Peter