"Changes" are what the 'jazzers' call chord changes. so playing the changes refers to navigating through chord changes. "Changes" can vary in levels of complexity. It can be a two chord vamp like Santana's, "Black Magic Woman", or more difficult like John Coltrane's "Giant Steps", or any composition by Allan Holdsworth, etc.
"Chord changes" refers to when you switch from one chord to another chord (although "the changes" oftens refers to a tonality switch as well). Usually when you hear the term "changes" it's referring to jazz or fusion music, since these styles often have more (and often more complex) chords than much of metal and rock.
As stated above, "changes" generally relates to a tonality change. For example, going from A minor to D minor is changing chords but you can continue to play the same scale over both chords because they are in the same tonality (in several actually: F major [A minor is Phrygian, D minor is Aeolian], or C major [A minor is Aeolian, D minor is Dorian], or A minor pentatonic). A lot depends on the context of the song, for example style, tempo, mood, knowledge level, the effect you're going for, your tastes, other chords, melody notes, etc.
A large part of playing changes is finding commonalities, common notes and common keys.
It's usually a good idea to take a look at (and do a little analyzing) of changes before jumping in, just to make sure there are no surprises; it sucks to shut your eyes and just "go for it" and then run into something unpleasant along the way - B7#11b13#9, for example.
I mean you should always just "go for it" when you are actually playing music, but right now we are studying and practicing; this is where we want to analyze, so we don't have to later. When we are playing music we can stop thinking, but we'll have a little road map and be aware of what is coming, so we can think and hear ahead.
There is a famous musical quote that "any note sounds good over any chord as long as it resolves well." I'm not sure who said it.
When I first started studying playing over changes, I used to try to play over every chord and treat it as it's own tonality center, after hearing and playing with some heavy musicians I admired, I found they were thinking ahead about the whole progression not just 'chord by chord'. This made it much easier to develop long flowing very musicial ideas, not just little 'blurbs' (yes guitarists, it helps you play a lot more notes too - so now are you interested!) Don't get me wrong, they are playing over every chord, but they are thinking of the whole progeression, not just each chord.
Take this progression as an example.
|| Eadd9/G# G/A | G/A | Aadd9/C# C/D | C/D ||
(If you're not familiar with these chord symbols, it's chord/bass note, so that first chord is E major triad add the 9th over G# as a bass note. Honestly I think this is the best, clearest and easiest way to write this chord and you'll know just what the chord means, but technically since G# is in the bass that is the root of the chord, you could call it G#-7b6 (no 5), G#-7b13 or Bsus/G# [see chord chart at bottom of this page]).
When I first saw these chords, I wanted to build chord scales off the root, since that is the bass of the chord, however it is more difficult to think of G#-7b6 than Eadd9/G#, the first chord can have many variations of a minor type chord, wheras the E chord, is a major of some sort, which narrows down your choice to major or domanant. So the first approach is to look at the notes in a chord and figure out how best to think about it for you. Then we need to look at all the chords togther as a whole.
So to approach this, rather than playing E major over the E add 9/G# | A Mixolydian or Aeolian over the G/A, A major over the A/C# and D Mixolydian or Aeolian over the C/D which may look right at first and may work but it also may cause some disconnect,
if we spend a minute to look for commonalities, we can see that:
Eadd9/G# = E F# G# B
G/A = G A B D
Aadd9/C# = A B C# E
C/D = C D E G
|----------------------------------------------|- |--5----------3---------10-----------8---------|- |--4----------4---------9------------9---------|- |--4----------5---------9------------10--------|- |----------------------------------------------|- |--4----------5---------9------------10--------|- Eadd9/G# G/A Aadd9/C# C/D
Now if we fill in these chord tones with some scalar guesses:
If we take some of the most common chord tones above and build a scale or scales and common notes out of it, we can see that, except for one note in the first chord, we can play G major over this whole progression - G A B C(#) D E F# G - or even - E G A B D = E minor pentatonic. Now this opens the field.
For example, we can play G major (careful on the second chord with the G#, although it works as melodic minor), or E minor pentatonic/blues scale/licks.
This first chord is also a great choice for the 5th position of A melodic minor - A B C D E F# G# A - a great jazz scale, learn it, use it!)
OK, granted this seems like a lot of work just to play guitar! This is why you do your homework and practice this stuff ahead of time, so when you 'just want to play', you don't have to think, you can play whatever you want.
I took the progression used in this lesson from a song off my debut album "Dajinosaurus" entitled "ILD" - it seemed like a good example for this lesson. You can hear some ideas I like to explore for the progression in the included excerpt. You can hear it here.
This just scratches the surface and discusses notes, We didn't talk about other important aspects, such as timing and chord duration. Obviously the chord you hear longer will seem more important than a passing chord, which is important to keep in mind when you are looking at a progression.
Here's some examples and audio for you to work with:
Solo over an "ILD" backing track.
Try scales over chords (no time).
An example of the above to get you started. Here's another one.
David Wright has been playing guitar over 20 years and has performed in many styles and situations, currently he is focused on composing and performing original instrumental guitar based music, in the high energy jazz-fusion realm.
A partial list of Influences would include: Mike Stern, Allan Holdsworth, Hiram Bullock, Frank Zappa, Shawn Lane, Wes Montgomery, Wayne Krantz, Scott
Henderson and Tribal Tech, among others.
His debut album is entitled "Dajinosaurus".