How do I tell a piece is in Maj or Min?

[phossill]

I'm learnng how to sight-read and I'm having a hard time telling whether a piece is in a major key or in it's relative minor. how do I tell if a piece is in C Maj or in A Min and if it's in a minor key how do i tell if its Natural min, Melodic min or Harmonic?

Help!!!

[randalljazz]

if it is the key of no sharps and flats---look at first chord, look at the last chord, and especially look at the last four measures.

if the last two chords are E7 and Am (and any chord extensions or alterations), then it is a good bet it is in A minor. if the last two chords are G7 and C (and any extensions, etc), then it is most probably in C.

if there are many instances of F# and G#, that also is an indication of A minor.

natural, harmonic, melodic are not three different keys, just different forms of the minor scale. so, if you determine that it is in A minor, and no F#'s or G#'s, then natural minor is the predominant sound. (unlikely). if there is F natural and G#, then harmonic minor is the sound (several tunes exploit this sonority). most likely you will find F#'s and G#'s, as well as the natural forms of both notes, which is by far most common, and will indicate the melodic minor sound.

rarely, it may be in minor and have F# but G natural, a dorian sound.

[phossill]

I've Just played the three minor scales and you're spot on!! that helps a lot

[BigDaddyLoveHandles]

As far as if it's C major or A minor, My first choice would be to listen to the piece! It's usually obvious. Beyond that, if it's piano music (or something similar) I cheat and look at the last bass note: is it C or A?

For example, here is a little vamp:

||: 6x576x 7x676x 8x788x 5x454x :||

That sounds major to me. The chords are:

Bb6: Bb G D F
Bdim7: B Ab D F
Cmi6: C A Eb G
Adim7 A Gb C Eb

And here is another vamp:

||: 3x333x 4x343x 5x554x 2x121x :||

That sounds minor to me. The chords are:

Gmin7: G F Bb D
Abdim7: Ab F B D
Amin7b5: A G C Eb
F#dim7 F# Eb A C

Note that the two progressions are built out of the same notes, chord by chord. Only the inversions are different.

[franco6719]

Use ya' ears....(;

[franco6719]

Seriously, I used to find it "impossible" myself, but it's a question of ear-training and time...