say i have a melody in b minor with my right hand....i can sort of hear what should accompanient it but sometimes i cant figure it out... is there a site that can explain how to figure it out
From your question about the chords to harmonize your melody, I assume that you have not completed the basic music theory sequence, so you need to do a bit of self education in regards to three forms of simple diatonic triads and the four forms of diatonic seventh chords.
There have been several excellent suggestions offered, but much to my surprise no one has suggested a couple of excellent learning tools. One is lead sheets and the other is simple counterpoint. First let's look at chords and their inversions. My apologies to all that the following is second nature. Diatonic Triads
Any diatonic triad consists of three tones, the root, the third, and the fifth. For example an F# minor chord is F#-A-C#.
I makes no difference in which order the tones are sounded. those three tones together make an F# minor chord. Diatonic Seventh Chords
A diatonic seventh chord is simply a diatonic triad with an added seventh such as an F# dominant seventh chord would be F#-A#-C#-E. Like the triads, those four tones sounded together always sounds an F# dominant seventh chord. Inversions
Obviously the lowest sounding note of a triad can be any of the three tones that make up a chord. Let's use an E major chord as an example. That chord is spelled E-G#-B.
- If the root of the chord is the lowest sounding note, the chord is said to be in root position. It makes no difference whether the next highest note is the G# or the B, it is still in root position.
- If the lowest sounding note of the chord is the third or the G#, the chord is said to be in first inversion. Like the root position chord whether the E or the B is the next note is immaterial.
- If the lowest sounding note of the chord is the fifth or the B, the chord is said to be in second inversion. Like the root position chord whether the E or the G# is the next note is immaterial. It's still a second inversion chord.
The same logic applies to seventh chords except when the seventh is the lowest sounding note the chord is said to be in third inversion.
What does all of this have to do with harmonizing your melody? Surprisingly, nothing and everything. The Lead Sheet Path
If you have access to a fake book with some songs you like and a keyboard, learn how to play those songs using the indicated chord. The process is fairly simple and once you catch on to it well enough that you can pick up a melodic line with the chords indicated above and simply sit and play it.
Start by picking a lead sheet that doesn't have more than one chord per measure, and then analyze it. Look at every note in the melody and determine which notes are chord tones of the chord indicated for that measure and which are not. Play the melody and support with the chord tones with with the inversions of the chord that allows the melody chord tone to be the highest pitch note of the chord. Don't worry about the left hand just yet. Just keep experimenting with the voicing of the chord in the right hand that gives ou the best sound for the melody. Once you have the chords worked out for the right hand, play the piece playing the root of the chord in the left hand. Once you've gained some confidence and proficiency, experiment with the third and the fifth as the lowest chord tone played in the left hand. when you've done this with several pieces, you'll begin to see certain patterns, and that should make harmonizing you melody much easier. The Counterpoint Route
The simplest and most complicated method of harmonizing your melody is by using the rules of counterpoint. There are several excellent references available for counterpoint, but one of the most concise to use as a starting point is the basic writeup on Wikipedia http://en.wikipedia.org/wiki/Counterpoint.
Start by writing a species one counter point line for the bass then go back and fill in the alto and tenor voices keeping the rules of simple counterpoint in mind. You should keep an eye to the chords to ensure they follow an expected progression, i.e., as close as possible to the circle of fifths. The Academic Solution
The most robust solution is to successfully complete the standard college level sequence in music theory, 18th century counterpoint, and 20th century counterpoint. (Therein lies the answer to your question about, "Where did you guys learn all this?")
I hope this helps without being too pendantic or obtuse.