Guitar chords that contain an additional bass note are known as slash chords, taking their name from how they’re written with two letters separated by a slash mark.
The theory behind these chords relies heavily on music intervals; one note can produce multiple other notes within its octave.
Major
There are a few essential chords you should learn on guitar; these chords form the backbone for many songs and should definitely be learned by anyone looking to start playing music on an instrument. These will also help strengthen fingers while giving an overall understanding of key signature.
D/F#, also referred to as a slash chord, is another major chord. Comprised of D, F# and A notes, it can either be played with its first inversion or second inversion depending on which sounds best with your song.
Oasis’ Wonderwall features this chord with its opening played with a capo on the second fret; this adds its characteristic sound while harmonizing with F# minor mode it inhabits. You’ll also hear it used by Yngwie Malmsteen (Billie Jean) and Carrie Underwood (“Before He Cheats”).
Minor
Minor chords can help give your chord progressions a blues and rock sound, or be used as the basis of creating more metal-sounding lead guitar riffs.
A basic minor chord includes three notes – root note, minor third and diminished fifth above it. This chord is frequently seen in rock music and should definitely be included in your toolbox.
Change up the shapes of these chords to become familiar with them; for example, try playing an E minor with an F# barre chord shape, or vice versa.
Another effective way of practicing minor chords is combining them with some major key chords, like major vi and minor vii, for added tension and rock edge in your song. One way of learning this technique is listening to classic rock songs like Ozzy Osbourne’s Crazy Train and Led Zeppelin’s Immigrant Song by Ozzy Osbourne or Led Zeppelin as examples of good examples of this combination of minor and major key chords.
Dominant
However, unlike major and minor chords which feature brighter tones or darker, more foreboding tones, dominant seventh chords often create tension by employing an interval with a flat seventh note which creates dissonance with their root note.
The Rolling Stones famously employed a dominant B7 chord on “(I Can’t Get No) Satisfaction,” to achieve a blues-meets-psychedelic rock sound. More recently, Blue Oyster Cult used a dominant G7 chord on their hit song, “Don’t Fear the Reaper,” to showcase their bluesy rock influences.
These movable dominant 7th shapes are based on closed voicings of chords with their lowest note on the fifth string, so to play these you must know how to play previous shapes and move them up or down fretboard accordingly. You can use these versatile chord forms along with other familiar chord voicings you have learned.
Mixolydian
The mixolydian scale is a ubiquitous sound in music. It is one of the most widely utilized scales for jazz and blues music, often associated with dominant 7 chords or chord progressions containing its lower seventh note.
Lowering this interval creates tension and dissonance, commonly found in rock and blues music. Mixolydian chords help balance this dissonance without clashing with the tonic chord.
Practice playing the lowered seventh of the mixolydian scale on both strings will enable you to more naturally perform chords in this mode. Furthermore, becoming acquainted with both major scale and blues scale notes will come in handy when using this mode.