#1
1.What is the forumula for a dominant 13 chord? Which notes can you omit and still have a 13 chord amd why?
2. Can someone show me and example of when you would a double flat or a double sharp?


Thanks guys
~Long live the 6-string~
#2
1-3-5-b7-9-11-13

You can omit the 5th, 9th, and 11th, technically. You'll sometimes see the third omited; and sometimes everything below the b7, depending on the situation. That's for the entire harmony, specifically for guitar you just have to pick up whatever notes you need to pick up *shrug*

You would use a double flat any time you need to lower a note a half step that's already flat, and not change it's letter name; the inverse is true for a double sharp. Double flats are most often seen in chromatic harmony, Cbm comes to mind; double sharps are pretty common in minor keys where the natural 7th is sharp (and thus needs to be double sharp to create a leading tone), and in similar places.
Quote by les_kris
Corwinoid is God
I'm not even God-like... I've officially usurped the Almighty's throne.
Click here to worship me.

Member #3 of the Corwinoid Fan Club
#3
first, a 13 chord is any chord that has the thirteenth degree of the scale in it, for example, an A minor chord is A-C-E, the minor 13th chord would be A-C-E-F, but that has omited notes. The Full 13th would look like this: A-C-E-G-B-D-F. so you can in theory omit all but the root and the 13, so it'd look like this: A-F. but that, depending on the context, could also be the beginings of a F Major chord.

second, a double flat or double sharp occors in weird key signatures, like F#, or E#. But they only really exist in theory, there's no real pratical use for them.
#4
Sniper's advice is correct, you really can ommit just about anything you want. As far as which notes are best to omit, sometimes it's a matter of positioning, and other times you have to be aware of what other people are covering. Bassists usually pick up the fifth, so that's the first to go. I've been told you want to hang on to the third and the seventh, cause they "define" the chord the most. I mean, the third is what gives it the major/minor tonality, and the 7th will further define it as major/minor/dominant/some-mixed-bastard-child-of-the-three. In playing them though, I've found just get like a chord patter or two under your belt and use that, or comp with a simpler chord.
#6
Quote by SEALSniper1152
first, a 13 chord is any chord that has the thirteenth degree of the scale in it, for example, an A minor chord is A-C-E, the minor 13th chord would be A-C-E-F, but that has omited notes. The Full 13th would look like this: A-C-E-G-B-D-F. so you can in theory omit all but the root and the 13, so it'd look like this: A-F. but that, depending on the context, could also be the beginings of a F Major chord.

second, a double flat or double sharp occors in weird key signatures, like F#, or E#. But they only really exist in theory, there's no real pratical use for them.
I hate to be the bearer of bad news, SEALSniper1152, but this is chock full o' errors. Corwinoid's absolutely right - it's just not worth the effort to try to straighten this out for you. In other words, your understanding of chord and key theory has some serious holes in it. I urge you to hook up with a competent teacher and/or buy and study Understanding How to Build Guitar Chords and Arpeggios by Michael Policastro.
All things are difficult before they are easy.
- Dr. Thomas Fuller (British physician, 1654-1734)
Quote by Freepower
For everything you need to know - gpb0216.