Yes, the chord tones follow the progression. If one listens closely to chord tone solos, one begins to notice that the phrases are centered on the root notes of the chords. Most guitar solos also start and end on the root note (a.k.a. the tonic) of the key in which a song is written.
Originally Posted by Rango
I wouldn't worry about the major diatonic and pentatonic scales at this point because the majority of the rock and blues tunes that you will encounter are written in minor keys or played with root 5 chords (e.g. B5, E5, F#5). A root 5 chord (a.k.a. a power chord) contains only a root note and a perfect 5th interval note. As the 3rd interval determines if a chord is a major or a minor chord, a root 5 chord lacks major/minor tonality; therefore, one can improvise using the parallel major and minor diatonic and pentatonic scales over a root 5 progression.
In the case where a song is written in a major key, one can get away with improvising in the parallel minor key using the minor pentatonic scale (e.g., Bm pentatonic over a B major progression) as long as one is careful with the notes numbered 3 and 7. These notes are one half step up in frequency in the major scale (see below). Not adjusting for this difference is one of the most common mistakes that beginning lead guitarists make when improvising using a parallel minor pentatonic scale over a major chord progression. These notes stick out like sore thumbs because they make the soloist sound like he/she is out of key.
Basic Scale Theory
Many of the members of the PRS Forum may already know some of this information. Please bear with me as I cover theory that you already know.
The fundamental scale in western music is the chromatic scale. The chromatic scale contains twelve notes. We start counting over again from one after we get to note number twelve. This distance is known as an octave. The 12th fret on a guitar is one octave up from the nut. The 24th fret on a guitar is two octaves up from the nut.
Other scales are created by applying interval patterns to the chromatic scale. An interval is the distance between the two notes in a scale (usually measured from the root note). In the case of a diatonic scale, we have seven notes; therefore, we have seven intervals between a scale's root note and the root note one octave higher in frequency. The intervals from the root note in a octave are numbered two through eight, with interval number eight being one octave up from the root (the word octave is derived from the Latin word octo, which means eight) . The interval pattern for a major scale is WWHWWWH, where the letter W denotes a whole step (two frets up) and the letter H denotes a half step (one fret up).
The twelve notes in B chromatic are B, C, C#, D, D#, E, F, F#, G, G#, A, and A#. If we apply the pattern WWHWWWH to B chromatic, we get the notes in the B major scale.
B, C, C#, D, D#, E, F, F#, G, G#, A, A#, B
W W H W W W H
The notes in B major are B, C#, D#, E, F#, G#, and A#.
The interval pattern for the natural minor scale (a.k.a. Aeolian mode) is WHWWHWW. Applying this pattern to the B chromatic yields B minor.
B, C, C#, D, D#, E, F, F#, G, G#, A, A#, B
W H W W H W W
The notes in B natural minor are B, C#, D, E, F#, G, and A.
Finally, the chromatic scale for any given key contains the same twelve notes as B chromatic. The only difference is the starting note. For example, E chromatic contains the notes E, F, F#, G, G#, A, A#, B, C, C#, D, and D#.
For the computer scientists and computer engineers on the forum, deriving any chromatic scale from another chromatic scale involves little more than a circular shift operation that places the root note of the key in ordinal position 0 within the ordered set. Additionally, in chords such as Em7add11, the mathematical relationship between the "add" portion of the chord and the base chord is the interval number of the note being added modulo seven. For example, 11 mod 7 = 4, which means that we are adding a fourth interval note to the chord. However, because the number is greater seven, we know that the note is in another octave. We determine the octave in relationship to the root note in which the note to be added occurs by computing the integer quotient of the number divided by seven. In this case, the integer quotient of 11 div 7 = 1 (where div denotes integer division), which means that we are adding the 4th interval note one octave above the root note to the chord.
Finally, a common chord that all rockers will encounter is E7#9 (a.k.a. the "Purple Haze" chord). E7#9 is composed of an E7 chord plus a sharp 9th interval. E7 is a what is known as a dominant seventh chord. A dominant seventh is a major chord plus a minor seventh interval. The fact that nine is greater than seven tells us that the sharp 9th note is at least one octave up from the root note. Applying modulo 7 to 9 yields 2. Because the note is a sharp 9th, it is a really a minor third one octave up. In essence, E7#9 gives us E7 (major-minor) and Em7 (minor-minor) tonality because the chord contains major and minor thirds.
THANK YOU for the post.