I know my weaknesses. I've never been a theory master but I know someone who is. Desi goes by the name of Mr. Guitar Theory for a reason. We've already looked at how the lead chords can stay the same over the changes but Desi can tell you why. Give him a warm welcome and feel free to ask questions in the comments section. He is a wealth of knowledge. -Jason
“Nothing Is Impossible” by Planetshakers is a straightforward composition in the key of C that draws all its notes and chords from the C major scale. Aside from a Dm7 chord, all chords are plain major and minor, but the use of sustained notes over the chord changes produces the sound of added chord tones and extensions.
The song opens with the chorus using C-G-Am-F, which is 1-5-6-4 in the C scale, and one of the most popular types of chord movements in music. You may see it written using Roman numerals like I-V-vi-IV, with upper case Roman numerals representing major chords and lower case representing minor chords.
During the chorus, the lead guitar repeats and sustains the notes C, G, and C on strings 3, 2, and 1, while the chords from above change underneath the part. When played along with the chord changes, the notes C and G produce additional harmony. Nothing new is heard on the C chord because it already has the notes C and G in it. The G chord, however, normally doesn’t include a C note. The addition of the C note over the G chord creates the sound of Gsus4. The Am chord sounds like Am7 when a G note is sustained over it, and the F chord sounds like Fadd9. All together, the multiple parts produce the sound of C-Gsus4-Am7-Fadd9. Later, when the Dm7 chord is introduced, you actually hear the sound of Dm11.
Sustaining notes over melodic lines or chord changes is called pedal point or pedal tones. The sustained notes become added chord tones and extensions, producing harmony that has more color and depth than plain major and minor chords. The pedal tone composition technique is an easy way to produce a complex sound by combining two simple parts. More often than not, the pedal tones are the tonic and dominant degrees of the scale, which are 1 and 5. Another way to think of them is as the root and 5th of the primary chord, in this case C and G from the C major chord. You hear something similar in U2’s “With Or Without You,” only in the key of D sustaining the notes D and A over the song’s D-A-Bm-G chord progression.
Sometimes pedal tones are added to guitar chord fingerings and the total sound is produced by just one player. A good secular example is “Wonderwall” by Oasis. The song is based on Em-G-D-A7, but with the notes D and G at the 3rd fret of strings 2 and 1 held and sustained on each chord shape. The end result is the much richer sound of Em7-G-Dsus4-A7sus4. Something similar is done in “Wish You Were Here” by Pink Floyd.
Editors note: You can try these ideas along with the "Nothing Is Impossible" lesson below.