While studying the circle of fifths and minor keys, I noticed that I could look up the relative minor chords to a key by simply looking at the key four away on the circle of fifths (c-a minor-c,g,d,a) and using the chords on either side (d,A,e). It's pretty obvious stuff, but I was wondering if there happened to be any tricks to figuring out the seventh chords, or any others, for that matter, in a key, without having to go through and construct each chord to see if there are any notes that don't fit with the key.
well a 7th would be a semitone lower for a major chord and a tone lower for a minor chord (although the actual note Ought to be played an octave higher). and the actual chord would just be the standard 1 3 5 chord so in the case of c major the chord with the 7th would be CEGB and C minor would be C Eb G Bb.
Fender American Deluxe Ash Stratocaster (2000)
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maj7 = 1 3 5 7
dom7 = 1 3 5 b7
min7 = 1 b3 5 b7
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