are all minor chords created by flatting the 3rd?
By flatting the third of a major chord, yes.

The real difference is in the interval. Major chords have a major third and minors have a minor third.
Yes, a the characteristic of a minor chord is the flatted third. However, it is not exclusive to minor chords, half diminished and diminished chords use the flatted third aswell.

Basically, in their most basic form (three note chords) chords can be put into a few categories.

Major chords = Root, Major third, Perfect fifth.
Minor chords = Root, Minor third, Perfect Fifth.
Diminished Chords = Root, Minor third, diminished fifth.
Augmented Chords = Root, Major third, Augmented fifth.
Suspended Chords = Root, suspended second or fourth, perfect fifth.

Those are the basic groups. But as said, all minor chords have a minor (flattened) third, but they are not the only chords that contain flattened thirds.
Fusion and jazz musician, a fan of most music.

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AWESOME!!!! Thanks for this.
Quote by Sickz

Major chords = Root, Major third, Perfect fifth.
Minor chords = Root, Minor third, Perfect Fifth.
Diminished Chords = Root, Minor third, diminished fifth.
Augmented Chords = Root, Major third, Augmented fifth.
Suspended Chords = Root, suspended second or fourth, perfect fifth.

Question: wouldnt that be a diminished triad? I remember reading somewhere that a diminished chord requires the bb7 as well, is that correct? Half diminished chord would require the b7 instead?

I dont know much about theory, I just remember reading this somewhere and Im seeking confirmation.

Thanks.
Quote by tappooh
Question: wouldnt that be a diminished triad? I remember reading somewhere that a diminished chord requires the bb7 as well, is that correct? Half diminished chord would require the b7 instead?

I dont know much about theory, I just remember reading this somewhere and Im seeking confirmation.

Thanks.

That is correct. Diminished chords don´t show their full quality until they become four note chords, cause as you said, they can either have a flat seventh or a double flattened seventh. I simply wrote it out as triads to give the example that the minor third interval is not exclusive to minor chords, but chords of the diminished group aswell, where i put both Half-Diminished and Diminished chords.
Fusion and jazz musician, a fan of most music.

Quote by Guthrie Govan
“If you steal from one person it's theft, and if you steal from lots of people it's research”

Quote by Chick Corea
"Only play what you hear. If you don't hear anything, don't play anything."