#2
YOU use them whenever you want unless style dictates otherwise. I use them to "spice" up arrangements which only use triads or when comping jazz to play 9ths off the bass player. Or honestly, in pretty much any style of music.

They're used in almost every style. Play a dominant 7th chord, if you had a nickel for every time someone used that you could rebuild Japan by yourself and still have enough to live comfortably the rest of your life.
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#3
You can use 7th chords whenever you feel like it.

I use dominant second chords at the end of a progression to resolve to the root chord. Say I have these chords:

Cmaj Fmaj Gmaj Cmaj, I am playing a I IV V I progression.

I can make all of those chords 7th chords: Cmaj7 Fmaj G7 Cmaj7

However, I can also leave them the same except for the V chord:

Cmaj Fmaj G7 Cmaj.

The dominant 7 chord is important because it gives you a stronger resolution to the root chord, which in this case, is Cmaj.

Play Gmaj and then Cmaj, then play G7 followed by Cmaj. The latter should sound like it resolves better.

(Buy a standard theory book like "ABRSM guide to music theory part 1 and part 2, Jazzology and Jazz for guitarists by Mark Levine. Good books they are).

Other than that, I cant help you really, I have only started to learn 7th chord theory in the last few weeks.
Sat in a lab, curing diseases. They actually LET me play with chemicals!
Last edited by Guitardude19 at Mar 27, 2011,
#4
if your looking for some nice non dissonent ways to play it,
you could do:

------------
-6-----------
-5-----------
------------
-5-----------
------------

or

--------
-8-------
-7-------
-5-------
-6-------
--------
#5
Quote by YesterdaysToday
if your looking for some nice non dissonent ways to play it,
you could do:

--------



The dissonance is what MAKES it a 7th chord.
Winner of the 2011 Virginia Guitar Festival

Protools HD
Lynx Aurora 16/HD192
Mojave, Sennheiser, AKG, EV etc mics
Focusrite ISA828 pres
Waves Mercury
Random Rack Gear

65 Deluxe Reverb
PRS CE 22
American Standard Strat
Taylor 712