Lead note, Bass note and Guide tone: Three essential elements of chords
When we play a chord, we mostly focus on the chord quality and they key. It is true that if we play the right type of chord on the correct key, it will sync with the song. However, to make the chord sound even more soothing to the ears and sound perfectly synced with the underlying melody, we need to understand the concept of Bass note, Lead note and Guide tone of a chord.
Bass note: The bass note of a chord is the heaviest sounding tone in the chord. A chord missing a heavy bass element will not sound very rich, specially if it is played in the absence of a bass guitar keeping the chord rhythm as the main harmony. Not all notes work well as the bass note. In a triad, the best sounding bass is the root note itself, the second best is the fifth and the weakest sounding bass is the third. For example, in a C chord, the notes are C (1) E (3) and G (5). The C note is going to sound best as the bass note, G will sound pretty good too but E will sound quite weak. The same order applies for additional chords too. For example, in a C Major 7 chord, the notes are C (1) E (3) G (5) and B (7). The same sequence applies here too with C being the best sounding bass and B being the weakest sounding bass.
Lead note: Lead note of a chord is the highest pitched note. There is no hard and fast rule on what lead note will sound best for a chord. However when we play a chord, we should try to keep the lead note of the chord same as the main note of the underlying melody. If the underlying melody is the vocal part of the song and on that chord, the singer is mostly singing the note G over a C chord, then we need to play the C chord in a way where G remains the highest note. This is the reason learning inversions of chords is so very essential. Setting up the chord right can make the sync between rhythm and harmony so much more pleasing to the ears.
Guide tone: Guide tones of a chord are the essential notes that define the chord’s core tonality. Foe example a major chord is bright and colourful. whereas a minor chord is relatively sad and dark. This difference is solely created by the third interval of both the chords (C major C E G and C minor C Eb G), therefore it can be said that the third interval is the guide tone of the major/minor triads. As a guitar player if we just played the root and the third excluding the fifth, we could still hear the major or minor tonality. For 7th chords, the guide tones are the 3rd and the 7th. So similarly, if we just play the root, third and 7th, we will be able to hear the core tonality of the chord even if we skip the fifth.