b5 substitute

b5 is the same thing as #4 or #11 and theyre all called tritones.

a tritone substitution, very basically, is where you substitute a tritone from the bass note for the actual bass note ONLY IN DOMINANT 7th CHORDS (not maj 7, min 7, etc.). For example...you have a C7 chord, if you want to tritone sub it youd replace the C with an F# creating the chord F# E G Bb, which gives you a b9 which creates considerable tension.

where this gets interesting and useful is in chord progressions. since you said youre gettin into jazz, then you should know the most common chord progression in jazz is the ii-V-I which means you have a minor 7 going to a dom 7 going to a major 7 (half dim 7, dom 7, minor 7 if youre in minor). If we stay in C, this prgression would be Dm7-G7-CM7. However, if you tritone sub the G7 (remember, only dominant chords can be subbed) then you replace the G with C#/Db. your progression now is Dm7-C#/Db7-CM7 which gives you a chromatically descending bass motion with considerable tension in the dominant (which is what theyre designed to do, but with the tritone sub you add outside notes from the scale like the b9 (C#/Db) which gives the listener a sense of, "whoa, something happened." Then when the dom7 chord resolves to the M7 then the resolution is enhanced.

Since most players add extensions to their dominant (and other) chords like the altered (raised or lowered) 9, altered 11, or altered 13 depending on the motion, tritone subs can change a chord to give the progression more color. if you tritone sub a C 13 (C E Bb A - most important notes) you end up with F# E Bb A which is a F#7(#9) more commonly known as the Hendrix chord. so theres some interesting things to be done with tritone subs.

in summary, the tritone sub is used commonly to create tension within common ii-V-I chord progressions and to create a chromatically descending bassline. The tritone, changes the dominant chord and adds extensions within the scale that enhance tension-release. tritone subs only work on Dominant 7th chords because the dominant chords are harmonic devices to strengthen the key center, and by adding more tension, the resolution is enhanced. tritone subbing a M7 or m7 would only lead to confusion as to what the actual key center is.

hope this helped. if anything is unclear ill clean it up.

what youre asking is called Secondary Dominants and refers to the analysis of tonal shifts in a piece. for examle when you see V/V, what that means is that chord is the V of V, so if were in C and a chord is marked V/V, that means its a D because G is the V of C and D is the V of G, so "five of five." what this is indicating is that the particular section youre in, the tonality is going to indicate the key is in G instead of C.

while secondary dominants are common place in all harmonic music (classical, jazz), the only time youll see V/V or V/ii or whatever is in an analysis. jazz lead sheets just write out the chords and its just assumed that the player is going to notice that the tonal center is moving.

secondary dominants arent really chord substitutions. their actual chords or harmonies that indicate a dominant of a chord in a scale OTHER than I. beethoven's waldstein sonata is an incredible example of complex secondary dominant usage. especially in the development section where the key changes extremely quickly.

for some advanced chordal substitution techniques, take the Coltrane approach. in Giant Steps (famous work, legendary for its crazy changes and perhaps the greatest example of improsiation known to man, buy the cd or burn it, whatever, just get it). Basically Giant Steps is a big ii-V-I, but Coltrane used major 3rd relationships to alter the boring ii-V-I. the first 3 bars of GS is essentially a ii-V-I, but the actual chords are BM7-D7-GM7-Bb7-EbM7. the target is EbM7, and Bb7 is the dominant, but look at the M7 chords. BM7, GM7 and EbM7 are all maj 3rds apart and instead of just playing a ii-V, he goes through the cycles of keys until he gets to Eb and along each change, he uses the dominant to resolve to that key, which is an excellent example of secondary dominants. D7 isnt in Eb, it 'should' be D half diminished 7, but since its D7 AND moving to a GM7 chord, that indicates that D7 isnt functioning as a part of Eb, but as a part of G and establishing G as the new tonal center. the rest of the A section is like that. after the EbM7, you have Am7-D7-GM7-Bb7-EbM7-F#7-BM7. thats a 4 bar phrase where BM7 is the target. since ii (in this case Am7) is very similar to V in terms of function, the Am7-D7 section is acting as a secondary dominant. Bb7 is establishing EbM7 as the new tonal center and F#7 is finally getting to the BM7.

sorry for being long winded, i just wanted to give you an example of secondary dominant usage in more modern music than beethoven or bach.

Spencer, I'm not 100% sure I agree with you there - I want to confirm this with a guitar in my hands (as I haven't had much of a chance to really get into theory for the lasy year or two). But, without further ado...

I'm pretty sure it's NOT a question of replacing the root with a b5 (as an aside, while they're enharmonic equivalents, the b5 of C is Gb). My memory is pretty shady from this point on, as I haven't played any real jazz since college (say, two years), but I think rather than just replacing the root, you replace then entire dom7 with a dom7 built off the b5.

Take a G7 chord - G-B-D-F. Now, build a dom7 off the b5, Db. This gives you Db, F, Ab, and Cb. Relative to G, that's your b5, 7, b9, and 3 (technically a diminished 4th, but once again, relative to G). Essentially, that's a G7b5b9. It might not be something you'd NECESSARILY want to play over a G, for an "inside" sounding harmony, but you could to add quite a lot of tension to a set of changes, or you could swap out a G7 for a Db7 in a chord progression and have it sound tense but workable.

I think we're talking about the same thing, as we end up on basically the same chord, but if you look at the notes in question in your example (Gb,E G, Bb), you'll notice that there isn't actually a b9 in there, so from a conceptual standpoint, you really DO need to replace the entire chord.

If you want to see why this works... The fundamental principle actually comes from another, even simpler, substitution. If you take a dom7 chord, and then compare it to a diminished 7th chord played one half step higher, you'll notice that they're exactly parallel, barring the root. So, if you swap out a dom7 for a dim7 a half step up, you get a chord that implies a 7b9. Now, because a dim7 chord is constructed of stacked minor thirds, this shape repeats every three frets up the neck. Shift it up once, and it's inverted over the b3 (M3 relative to our original dom7). Again, and it's over the b5 (5 relative to the original dom7). But, remember, by dropping just the root down a half step, you get a standard dominant 7th. If you do that, you have a standard dominant 7th chord that's implying a 7b5b9 within the harmonic context of that original 7th chord.

As an aside, that diminished 7th chord (and it's related inversions) make much more consonant sounding direct substitutions - no one will ever consider a b9 a "inside" substitution for a dominant, but it's a MUCH easier one to make work musically, and thus is a little more practical (while still giving you that walking bassline spencer was talking about)

I hope this helps... Despite my initial disclaimer, once I got warmed up a bit, this came back to me pretty clearly. I just hope I didn't get too long-winded and confusing.

-D

drew, youre absolutely right.

i just kept it kinda simple because its easier to grasp if you arent really familiar with it yet. but i did mention the b9 and the tritone is b5 so were basically taking different routes to the same destination.

i fail to see how there isnt a b9 in F#/Gb E G Bb. thats a F#/Gb7(b9) chord. F#/Gb is the root, G is the b9, Bb is the 3rd and E is the 7th. in terms of the scale, since we were talking in C, there isnt a C#/Db but i was refering to the actual chord.

dude, its cool. its so easy to get into a long-winded theory explanation because, at least from my POV, i want to explain more in detail and by the time im done its like, 300 words.

Andelusion, if you want to learn the jazz language, guitar is not the best way to go. horn players are the most significant, while guitar is catching up, but still kinda far behind. ill list the major players you should check out. you can get a bunch of their cds at any local library.

sax - Charlie Parker, John Coltrane, Sonny Rollins, Michael Brecker
trumpet - Miles Davis, Dizzy Gillespie, Freddie Hubbard, Clifford Brown
piano - Keith Jarrett, Herbie Han****, Chick Corea, Bill Evans
guitar - PAT METHENY, mike stern, wes montgomery, jimmy bruno (dude has major chops, good place to start gettin into jazz from rock, mike stern is a great stepping stone too because he plays with a rock attitude and distorted tone but plays sick jazz lines).

short list, many more, but these guys are all killer and good to check out

get Miles Davis' Kind of Blue and John Coltrane's Giant Steps and A Love Supreme, those are jazz lexicon albums that embody the art. when people say 'jazz' these are the albums theyre thinking of in terms of the sound.

Oh, gotcha, I thought you were taking from the perspective of the implied harmony, not the chord you're dropping in there itself.

Cool, I was hoping you would take my response as theoretical discussion rather than me trying to pick a fight (I wasn't, for the record ), so thanks for being cool.

I actually don't listen to a hell of a lot of jazz, I just think that theory is fun. However, if you want to hear my absolte favorite jazz guitarist, check out Kenny Burrell's "Midnight Blue" album. It's a great transition from the blues, as he's got this great funky/bluesy style, and SRV actually eneded up covering his "Chitlins con Carne" off this disc.

Kind of Blue is another great recommendation - everyone should own a copy of this one, if nothing else cause it's about the chillest CD in the world. as an aside, it had a HUGE impact on Duane Allman...

-D